impact of tooth replacement strategies on the nutritional status of partially-dentate elders

Or ig ina l a r t i c l e

Impact of tooth replacement strategies on the nutritionalstatus of partially-dentate elders

Gerald McKenna1, Patrick Finbarr Allen1, Albert Flynn2, Denis O’Mahony3, CristianeDaMata1, Michael Cronin4 and Noel Woods5

1Department of Restorative Dentistry, Cork University Dental School and Hospital, University College Cork, Cork, Ireland; 2School of Food and

Nutritional Sciences, University College Cork, Cork, Ireland; 3School of Medicine, University College Cork, Cork, Ireland; 4School of

Mathematical Sciences, University College Cork, Cork, Ireland; 5School of Policy Studies, University College Cork, Cork, Ireland

Gerodontology 2011; doi: 10.1111/j.1741-2358.2011.00579.x

Impact of tooth replacement strategies on the nutritional status of partially-dentate elders

Objective: To investigate the impact of tooth replacement on the nutritional status of partially dentate

older patients, and, to compare two different tooth replacement strategies; conventional treatment using

removable partial dentures and functionally orientated treatment based on the shortened dental arch.

Background: Amongst older patients, diet plays a key role in disease prevention, as poor diets have been

linked to numerous illnesses. Poor oral health and loss of teeth can have very significant negative effects on

dietary intake and nutritional status for elderly patients. There is evidence that good oral health generally,

has positive effects on the nutritional intake of older adults.

Materials and methods: A randomised, controlled clinical trial was designed to investigate the impact of

tooth replacement on the nutritional status of partially dentate elders. Forty-four patients aged over

65 years completed the trial, with 21 allocated to conventional treatment and 23 allocated to functionally

orientated treatment. Nutritional status was accessed at baseline and after treatment using the Mini

Nutritional Assessment (MNA) and a range of haematological markers.

Results: At baseline, relationships were observed between the number of occluding tooth contacts and

some measures of nutritional status. As the number of contacts increased, MNA scores (R = 0.16), in

addition to vitamin B12 (R = 0.21), serum folate (R = 0.32) and total lymphocyte count (R = 0.35), also

increased. After treatment intervention, the only measure of nutritional status that showed a statistically

significant improvement for both treatment groups was MNA score (p = 0.03). No significant between

group differences were observed from analysis of the haematological data.

Conclusion: In this study, prosthodontic rehabilitation with both conventional treatment and function-

ally orientated treatment resulted in an improvement in MNA score. Haematological markers did not

illustrate a clear picture of improvement in nutritional status for either treatment group.

Keywords: older patients, nutrition, partially dentate, removable dentures, shortened dental arch.

Accepted 4 August 2011

Introduction

Increasingly, it is accepted that there are interre-

lationships between oral health and general health,

particularly the chronic diseases of ageing1. As our

population continues to age, the importance of

understanding these interrelationships takes on

increased significance. Currently, the proportion of

adults over the age of 60 years is expanding rapidly

across European Union countries, including the

United Kingdom and the Republic of Ireland2. As

the older population has grown faster than the total

population, the proportion of older persons relative

to the rest of the population has increased consid-

erably. This trend will have wide ranging effects on

social, political and economic spheres as well as

presenting significant challenges for healthcare

delivery and public healthcare policy3.

From reviewing the current literature, it is

apparent that a number of oral diseases have risk

factors in common with systemic diseases such as

smoking, diet and glycaemic control4–6. However,

� 2011 The Gerodontology Society and John Wiley & Sons A/S 1

research has recently focused on possible bidirec-

tional relationships between oral diseases, particu-

larly inflammation of the periodontal tissues

(periodontal disease), and Cardiovascular Disease,

Diabetes Mellitus and Respiratory Disease.

Amongst older patients, diet also plays a key role

in disease prevention, as poor diets have been

linked to illnesses such as osteoporosis, athero-

sclerosis and bowel disease7. Although nutritional

state is influenced by factors such as age, socio-

economic status and general health, it would

appear that dental status is also significant. Poor

oral health and loss of teeth can have very signifi-

cant negative effects on dietary intake and nutri-

tional status for elderly patients8. As a result, the

American Dietetic Association9 recently stated that

oral health and nutrition have a synergistic bidi-

rectional relationship. There is evidence that good

oral health generally has very positive effects on

the nutritional intake of older adults10.

The aim of this study was to investigate the im-

pact of tooth replacement on the nutritional status

of partially dentate older patients, and, to compare

two different tooth replacement strategies. There

are currently no previously reported randomised

controlled clinical trials that compare the impact of

prosthodontic rehabilitation strategies on nutri-

tional status.

Materials and methods

Partially dentate patients attending Cork University

Dental Hospital seeking dental treatment were in-

vited to participate in the research study (Fig. 1).

Patients were included if they were aged 65 years

and older, had a minimum of six remaining natural

teeth in one arch, no evidence of dementia, were

able to have routine treatment in a dental chair and

could communicate in the English language. Par-

ticipants were each given an information sheet

detailing the proposed treatment options, and each

provided written informed consent. Patients were

randomly allocated to one of two treatment groups

using a random number generator stratified for age

and gender. Patient allocation was performed by a

member of staff not directly involved in the

research project.

Each patient received a detailed oral examination

with dental status recorded using the International

Caries Detection and Assessment System, Basic

Periodontal Examination, number of occluding

contacts, bleeding score and plaque score. Prior to

prosthodontic rehabilitation, all patients received

routine dental care as required including standar-

dised oral hygiene instruction, extraction of teeth

with a hopeless prognosis, periodontal treatment

and restoration of caries. Full ethical approval was

provided by the Cork University Teaching Hospitals

Ethics Committee.

Patients assigned to Group 1 (Conventional

treatment) had all missing natural teeth replaced

using a removable cobalt-chromium partial den-

ture (Fig. 2). Those assigned to Group 2 (Func-

tionally orientated treatment) were restored to 10

occluding tooth contacts using Resin Bonded

Bridgework (RBB) (Fig. 3). RBB was provided

using a standardised protocol that included mini-

Figure 1 Partially dentate female patient aged 74 years

before prosthodontic rehabilitation.

Figure 2 Sixty-seven-year-old female patient with

removable partial dentures replacing missing teeth (con-

ventional treatment).

Figure 3 Partially dentate patient aged 68 years reha-

bilitated using resin bonded bridgework (functionally

orientated treatment).

� 2011 The Gerodontology Society and John Wiley & Sons A/S

2 G. McKenna et al.

mal preparation of abutment teeth, adequate

thickness of retentive wings (minimum 0.7 mm),

chairside sandblasting of the bridgework and cemen-

tation using a composite resin cement (Panavia� F;

Kuraray Co. Ltd, Kita-Ku, Osaka, Japan).

Assessments of nutritional status were conducted

at baseline (prior to any prosthodontic rehabilita-

tion) and 1 month after treatment was completed.

Nutritional status was assessed using the Mini

Nutritional Assessment (MNA), which included

anthropometrical measurements in addition to a

global assessment, and using haematological bio-

markers. Blood samples were taken from patients

and analysed for a range of markers including a full

blood count, serum folate, vitamin B12, ferritin,

albumin and vitamin D.

Data were collated and entered using Microsoft

Excel (Microsoft� Office Excel 2000). At baseline,

correlations between the number of occluding

tooth contacts and nutritional status were analysed

using a Pearson’s Correlation Coefficient and a

Chi-squared Test. After prosthodontic rehabilita-

tion, pre-operative and post-operative nutritional

measures were compared using a Student’s T-test.

Data were analysed using SPSS� (SPSS, IBM

Corporation, Armonk, NY, USA) and statistical

significance was determined at p £ 0.05.

Results

Descriptive statistics

In total, 44 patients completed the trial in Cork

University Dental Hospital (Fig. 4). Eighty-six pa-

tients from were invited to participate in the study.

Sixteen patients did not meet the inclusion criteria

for the trial and were excluded, whereas 26 did not

complete the initial operative phase of treatment.

The patient pool consisted of 28 women and 16

men with an average age of 68.2 years (range

65–82 years). Twenty-one patients were allocated

to conventional treatment (Group 1) compared

with 23 who were allocated to functionally orien-

tated treatment (Group 2) (Table 1). All the mem-

bers of the conventional treatment group received

their allocated treatment; however, two patients

from the functionally orientated group refused their

allocated treatment and received conventional

treatment instead. These patients were analysed

according to the intention to treat principle.

Baseline findings

Within the sample of 44 patients, a range of 4–9

occluding contacts was recorded at baseline.

Occluding contacts were recorded where there was

contact between natural teeth in addition to nat-

ural teeth occluding against fixed or removable

prostheses that were not scheduled for replace-

ment.

Analysis of the haematological data illustrated

that as the number of occluding contacts increased,

there was a corresponding increase in levels of

vitamin B12, serum folate and total lymphocyte

count. The same relationships were not recorded

for serum ferritin, albumin or cholesterol.

For vitamin B12, all the samples recorded at

baseline were within the normal range (120–

650 ng/l). With an increase in occluding tooth

contacts, the levels of vitamin B12 also increased

giving an R value of 0.21 calculated using a Pear-

son’s correlation coefficient (Fig. 5). When the

results recorded for the minimum (four contacts)

and maximum number of occluding contacts (nine

contacts) were compared using a chi-squared test,

there was a highly statistically significant difference

(p < 0.001). Three patients were deficient in serum

folate at baseline (normal range 2.3–20 ng/l). As

the number of occluding contacts increased, serum

folate levels also increased with an R value of 0.32

recorded (Fig. 6). For serum folate, there was not a

statistically significant difference between the

results recorded for the minimum and maximum

number of occluding units (p = 0.82). A similar

relationship was found between number of

occluding contacts and total lymphocyte count. The

trendline illustrated that as the number of occlud-

ing contacts increased, the total lymphocyte count

also increased. An R value of 0.35 was calculated

for this relationship with a p-value of 0.80 (Fig. 7).

At baseline, the MNA indicated that 52.3% of the

participants were ‘well nourished’, with 40.9% ‘at

risk of malnutrition’ and 6.8% ‘undernourished’

(Table 2). In general, it was found that as the

number of occluding contacts increased, the MNA

scores also improved with an R value of 0.16

recorded and a p-value of 0.84 (Fig. 8).

Findings after treatment intervention

One month after prosthodontic intervention, the

MNA and haematological samples were repeated

(Table 3). For total lymphocyte count, the average

level declined for all patients from 2.2 · 109/l at

baseline to 1.86 · 109/l, 1 month after treatment

intervention. For vitamin B12, the average result

increased from 215.03 to 220.76 ng/l. A larger in-

crease in average level was found in the con-

ventional treatment group (229.85–237.57 ng/l),

but the results were not statistically significant


Impact of tooth replacement on nutrition 3

(p = 0.68). For both serum folate and ferritin, the

levels decreased after treatment was completed, but

the results were not statistically significant for the

entire study population or the treatment sub-

groups. A decrease in the levels of vitamin D was

also recorded for the conventional treatment group

and for the entire study sample, but in the func-

tionally orientated group, average levels of vitamin

D increased from 61.95 nM at baseline to 65.37 nM

post-operatively (p = 0.37). For albumin, an in-

crease in levels was recorded for both intervention

groups, but neither result was statistically signifi-

cant. For cholesterol, the average level recorded

increased for the conventional group, but

decreased for the functionally orientated group

(from 4.55 to 4.50 mM).

For the MNA, the whole study population

recorded an average of 23.65 pre-operatively,

which increased to 24.50 after treatment inter-

vention (p = 0.03). A similar finding was recorded

for the conventional group where an average

baseline score of 23.65 increased to 24.75

(p = 0.03). For the functionally orientated group,

the average baseline score of 23.24 improved to

24.37 after treatment (p = 0.03). MNA was the

only measure that indicated a statistically signifi-

cant difference in nutritional status after treatment

intervention.

Discussion

Evidence suggests that nutritional status is a

multifactorial condition. Whilst dental status may

have a role to play, other factors including socio-

economic class, income levels and learned behav-

iour patterns are also very important11. In this

ExcludedNot meeting inclusion criteria (16)Declined to participate (26)

Randomised (44)stratified for:

AgeGender

Allocated to FUNCTIONAL TREATMENT(n = 23)

Received allocated treatment (n = 21)Did not receive allocated treatment (n = 2)2 Patients declined functional treatment. Received conventional treatment

1 month post treatmentLost to Follow Up (n = 0)

Treatment discontinued (n = 0)

Analysed (n = 23)Excluded from analysis (n = 0)


Allocated to CONVENTIONAL TREATMENT (n = 21)

Received allocated treatment (n = 21)Did not receive allocated treatment (n = 0)

1 month post treatmentLost to Follow Up (n = 0)


Analysed (n = 21)Excluded from analysis (n = 0)


Enrollment

Allocation

Follow-Up

Analysis

Assessed for eligibility(n = 86)

Figure 4 Study flow diagram.


4 G. McKenna et al.

study, whilst the methodology was well con-

structed, it was impossible to control for all of

these potentially confounding variables. A rela-

tively small sample of patients completed the

research trial, and from the results obtained, it is

unlikely that the study had sufficient statistical

power to detect significant differences. However,

the results obtained may inform future studies by

providing information for power calculations. The

patients were followed for only a short period of

time after prosthodontic intervention. The benefits

of tooth replacement may require a longer period

to manifest through haematological markers

especially those stored in the body including fat-

soluble vitamins. It is encouraging, however, that

subjectively MNA scores indicated an improve-

ment in nutritional status, which may persuade

patients to improve their diets over a longer per-

iod. However, a targeted dietary advice pro-

gramme after prosthodontic intervention may be

necessary to improve outcomes as demonstrated in

other studies12.

Baseline results showed encouraging findings

linking nutritional status to the number of

occluding tooth contacts. It has been clearly shown

that a functioning dentition is an important factor

in healthy and varied diets amongst older patients.

An impaired dentition often leads to changes in

dietary habits during old age, which may impact

100

150

200

250

300

350

400

450

500

0

50

4 5 6 7 8 9

Vit

amin

B12

(n

g/l)

Number of occluding contacts (n)

Figure 5 Relationship between number of occluding

contacts and vitamin B12 (R = 0.21).

0

2

4

6

8

10

12

14

16

18

20

4 5 6 7 8 9

Ser

um

fo

late

(n

g/l)

Occluding contacts (n)


tooth contacts and serum folate (R = 0.32).

0.5

1

1.5

2

2.5

3

3.5

4 5 6 7 8 9

To

tal l

ymp

ho

cyte

co

un

t (×

109 /

l)



tooth contacts and total lymphocyte count (R = 0.35).

Table 1 Demographic profiles of trial participants.

Group 1

Conventional

treatment

Group 2

Functionally

orientated

treatment

Number of

participants (n = 44)

21 23

Gender

Female (%) 61.9 65.2

Male (%) 38.1 34.8

Age

Mean 67.3 68.8

Range 65–77 65–82Table 2 Mini Nutritional Assessment (MNA) scores

recorded at baseline.

MNA score <17 17–23.5 >24

Description Under-nourished At risk Well

nourished

Patients (n) 3 18 23

Patients (%) 6.8 40.9 52.3

10

12

14

16

18

20

22

24

26

28

30

4 5 6 7 8 9

MN

A s

core



tooth contacts and Mini Nutritional Assessment (MNA)

Score (R = 0.16).



upon nutrient intake. It was demonstrated that for

vitamin B12, serum folate and total lymphocyte

count the levels recorded increased as the number

of occluding tooth contacts increased. A weak

association was also shown between MNA and the

number of occluding contacts (R = 0.16). From

these baseline results, it could be extrapolated that

increasing the number of occluding contacts

through prosthodontic rehabilitation would have a

similar improvement in nutritional status.

However, 1 month after treatment, the measures

of nutritional status did not change significantly in

many cases. For total lymphocyte count, the aver-

age level decreased after treatment intervention

with a similar result recorded for serum folate and

ferritin. Levels of vitamin B12 increased after

treatment, but neither the result nor the increase in

albumin was statistically significant.

An increase was observed in the levels of vitamin

D amongst the functionally orientated group, but

this was not statistically significant. The only mea-

sure of nutritional status that indicated statistically

significant findings was the MNA. For the whole

study population as well as the two treatment arms, a

statistically significant improvement was recorded in

nutritional status. Although MNA includes a sub-

jective element contained within the global assess-

ment, it is a validated and reproducible tool that has

been described widely in the literature13.

As the population ages, public health initiatives

have focused on promoting positive ageing

including the need for healthy diets14. There is

evidence that particular nutrients are very impor-

tant in disease prevention in older patients.

Vitamin D is essential in protecting against osteo-

porosis, with currently one in every three women

Table 3 Nutritional status of participants before and after treatment intervention.

All participants (n = 44)

Mean (SD)

Conventional group (n = 23)

Mean (SD)

Functional group (n = 21)

Mean (SD)

Total lymphocyte count (·109/l)

Baseline 2.02 (0.61) 1.98 (0.55) 2.06 (0.69)

1 month post-operative 1.86 (0.76) 1.89 (0.69) 1.83 (0.85)

p 0.09 0.37 0.15

Vitamin B12 (ng/l)

Baseline 215.03 (100.36) 229.85 (119.72) 196.32 (67.27)


p 0.59 0.68 0.62

Serum folate (ng/ml)

Baseline 9.31 (6.06) 8.5 (5.65) 10.34 (6.55)


p 0.47 0.64 0.57

Serum ferritin (ng/ml)

Baseline 120 (113.60) 139.29 (130.54) 95.63 (84.95)


p 0.41 0.39 0.96

Albumin (g/l)

Baseline 39.79 (3.80) 39.79 (4.55) 39.79 (2.68)


p 0.06 0.20 0.16

Cholesterol (mmol/l)

Baseline 4.67 (1.02) 4.77 (1.21) 4.55 (0.71)


p 0.73 0.50 0.50

Vitamin D (nmol/l)

Baseline 59.47 (26.31) 57.50 (29.31) 61.95 (22.49)


p 0.50 0.16 0.37

Mini nutritional assessment score

Baseline 23.65 (3.10) 23.65 (3.01) 23.24 (3.27)


p 0.03 0.03 0.03


6 G. McKenna et al.

and one in every 12 men aged 55 years and older

affected in the United Kingdom15. Studies from

around the world have clearly demonstrated that

poor vitamin D status is common amongst older

adults, particularly those from Northern Eur-

ope16,17. Amongst the study population reported in

this article, 74% of participants were deficient in

Vitamin D at baseline compared with 71% after

treatment intervention. There is also further

evidence that vitamin D may play an important

role in the prevention of osteoarthritis18.

Despite the rise of obesity throughout the general

population, malnutrition remains common in older

patients, particularly those living in nursing

homes19. In this study of free living older adults,

whilst only 6.8% of the population could be clas-

sified as ‘malnourished’ at baseline, a further

40.9% were classified as being ‘at risk of malnu-

trition’. As malnutrition represents a deficiency of

all nutrients, and not just the calories, this can be

accompanied by a range of health problems

including impaired immune response, poor wound

healing and an increased risk of hospital admis-

sions.

Dental health surveys indicate that the oral

health of our older population is improving with

more natural teeth retained into old age20. How-

ever, factors such as xerostomia, polypharmacy

and reduced manual dexterity can mean that

preservation of these teeth can be challenging.

Given these circumstances, it is important that

practitioners consider treatment options for par-

tially dentate older patients, which can be main-

tained without contributing to further dental

disease and tooth loss. Unfortunately, it has been

shown that removable partial dentures can in-

crease the potential for dental disease including

caries and periodontitis. As an alternative treat-

ment strategy, the shortened dental arch can pro-

vide a functional dentition without the need for a

removable prostheses21. Given the fact that the

change in nutritional status was broadly similar for

both treatment groups, the positive attributes of

the shortened dental arch should still encourage

practitioners to consider this strategy for partially

dentate elders.

Conclusions

Nutrition and diet are important factors in disease

prevention especially amongst the elderly popula-

tion. In this study, patients indicated that after

prosthodontic rehabilitation with either a conven-

tional or functionally orientated approach, their

nutritional status improved according to the MNA.

Apart from this measure of nutritional status,

which contains a subjective element, haematolog-

ical biomarkers did not demonstrate a clear picture

of improvement for either treatment group.

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Correspondence to:

Gerald McKenna, Department of Restorative

Dentistry, Cork University Dental School and

Hospital, University College Cork, Cork, Ireland.Tel.: +353 021 420 5033

Fax: +353 021 490 1193

E-mail: [email protected]


8 G. McKenna et al.

impact of tooth replacement strategies on the nutritional status of partially-dentate elders

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