Risk indicators associated with root caries in independently living older adults

Abstract

Objective

To determine the risk indicators associated with root caries experience in a cohort of independently living older adults in Ireland.

Methods

The data reported in the present study were obtained from a prospective longitudinal study conducted in a cohort of independently living older adults (n = 334). Each subject underwent an oral examination, performed by a single calibrated examiner, to determine the root caries index and other clinical variables. Questionnaires were used to collect data on oral hygiene habits, diet, smoking and alcohol habits and education level. A regression analysis with the outcome variable of root caries experience (no/yes) was conducted.

Results

A total of 334 older dentate adults with a mean age of 69.1 years were examined. 53.3% had at least one filled or decayed root surface. The median root caries index was 3.13 (IQR 0.00, 13.92). The results from the multivariate regression analysis indicated that individuals with poor plaque control (OR 9.59, 95% CI 3.84–24.00), xerostomia (OR 18.49, 95% CI 2.00–172.80), two or more teeth with coronal decay (OR 4.50, 95% CI 2.02–10.02) and 37 or more exposed root surfaces (OR 5.48, 95% CI 2.49–12.01) were more likely to have been affected by root caries.

Conclusions

The prevalence of root caries was high in this cohort. This study suggests a correlation between root caries and the variables poor plaque control, xerostomia, coronal decay (≥2 teeth affected) and exposed root surfaces (≥37). The significance of these risk indicators and the resulting prediction model should be further evaluated in a prospective study of root caries incidence.

Clinical significance

Identification of risk indicators for root caries in independently living older adults would facilitate dental practitioners to identify those who would benefit most from interventions aimed at prevention.

Introduction

In many industrialised countries, as birth rates fall and life expectancy increases, the proportion of older adults within the general population is increasing. This trend is predicted to continue at pace in the twenty first century . While the prevalence of chronic medical conditions is high in this cohort, large longitudinal population studies into ageing have shown that an increasing number of older adults are independently living, mobile and active in their communities . With increasing numbers of patients retaining natural teeth into old age, the challenge of providing oral healthcare for the ageing population is undoubtedly going to increase. An increase in exposed root surfaces in the over 65 age group predisposes this group to a higher prevalence of root caries than younger populations . Estimating the prevalence of root caries can be challenging as loss of teeth confounds the data and diagnostic criteria and methods of reporting the data differ between studies .

A 2010 systematic review on the risk indicators of root caries suggested that future research should focus on variables which they found to be significant across a number of studies. These included age, gender, number of teeth at baseline, plaque index, lactobacilli counts, mutans streptococci counts, smoking, saliva flow rate, saliva buffer capacity, dental visit pattern, race/ethnicity, interdental cleaning, attachment loss, partial denture wearing, and gingival recession.

The main objective of the present study was to investigate the relationship between root caries in a cohort of independently living older adults and the variables outlined above.

Materials and methods

Study design

The data reported in the present study were baseline recordings obtained at the beginning of a prospective longitudinal study conducted on the risk factors associated with root caries incidence in a cohort of independently living older adults. The study protocol was submitted and given full ethical approval by the Clinical Ethics Committee of the Cork Teaching Hospitals (ECM 4 Y 06/12/11). The study was conducted in compliance with the principles of the Declaration of Helsinki and written informed consent was obtained from each participant. Eighty-five of the individuals whose data are included in this report were also subsequently enrolled in a randomised controlled clinical trial comparing restorative materials in the operative treatment of root caries .

Recruitment

Adults aged over 65 years of age with any of their remaining natural dentition were invited to attend Cork University Dental School and Hospital for a free dental examination. Advertisements were placed in local shopping centres, community centres and the local press over a period of three months. Telephone contact details of the study co-ordinator were provided and patients were allocated appointments provided they were the appropriate age, and confirmed they had some of their natural dentition remaining. All of the patients recruited to the study were independently living older adults. No financial rewards were offered to patients. Recruitment commenced in October 2012 and was completed in November 2013.

Inclusion and exclusion criteria

The inclusion criteria for entering this study were:

  • Aged 65 or over

  • Present a minimum of one natural tooth

  • Living independently in the community

  • Have sufficient cognitive ability to understand consent procedures

The exclusion criteria for this study were:

  • Those living in nursing home facilities

  • Individuals requiring antibiotic prophylaxis for periodontal probing

Data collection and oral examination

Each participant was interviewed by a research assistant prior to the dental examination. During this, the research assistant completed a data collection form which recorded age, gender, education level, medical history, fluoride exposure, oral and denture hygiene practices, smoking and alcohol consumption, and diet information. The medical history form used was the standard form used throughout the dental hospital and the remaining questions were selected from the National Survey of Adult Oral Health 2000–2002 General Health Questionnaire . The subject’s health was classified into one of four categories based on a system developed by the American Society of Anaesthesiologists (ASA). In this classification:

  • ASA 1 is a normal healthy patient without systemic disease.

  • ASA 2 is a patient with mild to moderate systemic disease.

  • ASA 3 is a patient with severe systemic disease that limits activity but is not incapacitating.

  • ASA 4 is a patient with severe systemic disease that limits activity and is a constant threat to life.

A single trained and calibrated examiner performed a baseline oral exam in a standard dental operatory equipped with a dental light and air-water syringe. Patients were advised to avoid eating, drinking, smoking, chewing gum, tooth brushing, or mouthwashes for one hour prior to their appointment. Saliva was collected over a period of five minutes following one minute of stimulation by having the participant chew a paraffin pellet. Xerostomia was defined as a stimulated saliva flow rate of < 0.7 ml saliva/min.

The CRT ® Caries Risk Test (Ivoclar-Vivadent, Schaan, Liechtenstein) was used to record the salivary buffer capacity and counts of mutans streptococci (MS) and lactobacilli (LB). The buffer capacity of stimulated saliva was determined using CRT Buffer ® (Ivoclar-Vivadent). The test field of the buffer strip was wetted entirely with stimulated saliva using a pipette. After 5 min of reaction, a coloured chart provided by the manufacturer was used to record the buffer capacity as low, medium or high. The MS and LB counts per millilitre saliva were recorded using CRT Bacteria ® (Ivoclar-Vivadent). The agar surfaces were wetted with stimulated saliva and incubated at 37 °C (99 °F) for 48 h. The MS and LB counts were scored in two categories: <10 5 or ≥10 5 CFU/ml saliva.

Plaque scores were recorded at baseline using the mucosal plaque score (MPS) index . A WHO Basic Periodontal Examination (BPE) probe was used to evaluate the periodontal condition, the presence of calculus and loss of attachment. The diagnostic threshold for periodontal disease was any pocket in the patient’s mouth where the black-band of a BPE probe (3.5–5.5 mm) partially or totally disappeared (i.e. BPE code 3 or greater). Denture wearing was recorded at baseline. Teeth were cleaned with an ultrasonic scaler, rubber cup and prophy paste and were washed and dried prior to caries detection. In this study, coronal caries visible into dentine, which had not cavitated but appeared as a definite shadow under the enamel (visual caries), was coded in the same manner as cavitated coronal caries. Decayed, missing and filled teeth (DMFT) were recorded. Root surfaces were anatomically defined as those surfaces apical to the cementoenamel junction (CEJ).

The root caries classification system used was a modification of the International Caries Detection and Assessment System (ICDAS II) as described in Table 1 . Each root surface was assigned two codes. The threshold applied to define a root surface as carious in this study was a Code 2 caries lesion code in combination with a Code 3 caries activity code, indicating a cavitated lesion of at least 0.5 mm depth which offers no resistance to probing with a ball-ended BPE probe. Secondary caries around an existing root surface restoration was scored in the same manner as a primary carious lesion.

Table 1
Modified international caries detection and assessment system (ICDAS II).
Caries lesion code Caries activity code
M Tooth is missing M Tooth is missing
E Root surface cannot be visualised E Root surface cannot be visualised
F Root surface is filled and sound F Root surface is filled and sound
0 No discolouration or loss of contour 0 Caries free
1 Discoloured but no cavitation 1 Arrested; Smooth, shiny and hard
2 Discoloured with cavitation (≥0.5 mm) 2 Quiescent; Leathery to gentle probing
3 Active; No resistance to gentle probing

Statistical analyses

Data from case report forms were entered into SPSS (version 22; SPSS, Inc., an IBM Company, Chicago, IL, USA) software. Fifteen participants were re-examined one week after initial exam. Intra-examiner reproducibility at root surface level was measured by the kappa statistic which was 0.95 for root caries detection indicating high rater reliability. DMFT scores were calculated from a maximum of 32 teeth. Decayed and filled root surfaces (RDFS) was calculated by adding the number of decayed and the number of filled root surfaces. A filled root surface which had secondary decay was categorised as a decayed root surface. Root caries index (RCI) was calculated as follows, [(number of decayed root surfaces) + (number of filled root surfaces)]/(total number of sound and decayed exposed root surfaces) × 100 . The data were described in bivariate tables. Normality was assessed by histograms, normal Q–Q plots, skewness values and their standard errors. For normally distributed data or normally distributed transformed data compartisons were made using a tw-sample t -test. Otherwise the non-parametric tests Mann Whitney U or Kruskal-Wallis were performed. P -values less than 0.05 were considered statistically significant.

Univariate and multivariate logistic regression analyses with the proportion of individuals with root caries experience (filled root surfaces or active root caries lesions) as the dependent variable were undertaken. This variable was dichotomized; subjects with RDFS > 0 were given a value of 1, and those with an RDFS = 0 were given a value of 0. The independent variables included were age, gender, final level of education, ASA category, alcohol consumption, smoking, fluoridated water supply, denture wearing, dental attendance, plaque control, tooth brushing frequency, interdental cleaning, periodontal disease, xerostomia, saliva buffering capacity, strep mutans count, lactobacilli count, number of teeth with coronal decay, number of missing teeth, number of teeth with coronal restoration, and number of exposed root surfaces. The continuous variables (number of teeth with coronal decay, number of missing teeth, number of teeth with coronal restorations, and number of exposed root surfaces) were dichotomized using the last quartile of the frequency distribution of that variable as the cut-off point. This reduced the continuous variables (which were recorded as a numerical value) into categorical variables to facilitate entry into the regression analyses.

The final model was chosen based on the backward elimination process, starting with the full independent variables, followed by subsequent removing of nonsignificant individual independent variables until no other nonsignificant independent variable could be removed.

Materials and methods

Study design

The data reported in the present study were baseline recordings obtained at the beginning of a prospective longitudinal study conducted on the risk factors associated with root caries incidence in a cohort of independently living older adults. The study protocol was submitted and given full ethical approval by the Clinical Ethics Committee of the Cork Teaching Hospitals (ECM 4 Y 06/12/11). The study was conducted in compliance with the principles of the Declaration of Helsinki and written informed consent was obtained from each participant. Eighty-five of the individuals whose data are included in this report were also subsequently enrolled in a randomised controlled clinical trial comparing restorative materials in the operative treatment of root caries .

Recruitment

Adults aged over 65 years of age with any of their remaining natural dentition were invited to attend Cork University Dental School and Hospital for a free dental examination. Advertisements were placed in local shopping centres, community centres and the local press over a period of three months. Telephone contact details of the study co-ordinator were provided and patients were allocated appointments provided they were the appropriate age, and confirmed they had some of their natural dentition remaining. All of the patients recruited to the study were independently living older adults. No financial rewards were offered to patients. Recruitment commenced in October 2012 and was completed in November 2013.

Inclusion and exclusion criteria

The inclusion criteria for entering this study were:

  • Aged 65 or over

  • Present a minimum of one natural tooth

  • Living independently in the community

  • Have sufficient cognitive ability to understand consent procedures

The exclusion criteria for this study were:

  • Those living in nursing home facilities

  • Individuals requiring antibiotic prophylaxis for periodontal probing

Data collection and oral examination

Each participant was interviewed by a research assistant prior to the dental examination. During this, the research assistant completed a data collection form which recorded age, gender, education level, medical history, fluoride exposure, oral and denture hygiene practices, smoking and alcohol consumption, and diet information. The medical history form used was the standard form used throughout the dental hospital and the remaining questions were selected from the National Survey of Adult Oral Health 2000–2002 General Health Questionnaire . The subject’s health was classified into one of four categories based on a system developed by the American Society of Anaesthesiologists (ASA). In this classification:

  • ASA 1 is a normal healthy patient without systemic disease.

  • ASA 2 is a patient with mild to moderate systemic disease.

  • ASA 3 is a patient with severe systemic disease that limits activity but is not incapacitating.

  • ASA 4 is a patient with severe systemic disease that limits activity and is a constant threat to life.

A single trained and calibrated examiner performed a baseline oral exam in a standard dental operatory equipped with a dental light and air-water syringe. Patients were advised to avoid eating, drinking, smoking, chewing gum, tooth brushing, or mouthwashes for one hour prior to their appointment. Saliva was collected over a period of five minutes following one minute of stimulation by having the participant chew a paraffin pellet. Xerostomia was defined as a stimulated saliva flow rate of < 0.7 ml saliva/min.

The CRT ® Caries Risk Test (Ivoclar-Vivadent, Schaan, Liechtenstein) was used to record the salivary buffer capacity and counts of mutans streptococci (MS) and lactobacilli (LB). The buffer capacity of stimulated saliva was determined using CRT Buffer ® (Ivoclar-Vivadent). The test field of the buffer strip was wetted entirely with stimulated saliva using a pipette. After 5 min of reaction, a coloured chart provided by the manufacturer was used to record the buffer capacity as low, medium or high. The MS and LB counts per millilitre saliva were recorded using CRT Bacteria ® (Ivoclar-Vivadent). The agar surfaces were wetted with stimulated saliva and incubated at 37 °C (99 °F) for 48 h. The MS and LB counts were scored in two categories: <10 5 or ≥10 5 CFU/ml saliva.

Plaque scores were recorded at baseline using the mucosal plaque score (MPS) index . A WHO Basic Periodontal Examination (BPE) probe was used to evaluate the periodontal condition, the presence of calculus and loss of attachment. The diagnostic threshold for periodontal disease was any pocket in the patient’s mouth where the black-band of a BPE probe (3.5–5.5 mm) partially or totally disappeared (i.e. BPE code 3 or greater). Denture wearing was recorded at baseline. Teeth were cleaned with an ultrasonic scaler, rubber cup and prophy paste and were washed and dried prior to caries detection. In this study, coronal caries visible into dentine, which had not cavitated but appeared as a definite shadow under the enamel (visual caries), was coded in the same manner as cavitated coronal caries. Decayed, missing and filled teeth (DMFT) were recorded. Root surfaces were anatomically defined as those surfaces apical to the cementoenamel junction (CEJ).

The root caries classification system used was a modification of the International Caries Detection and Assessment System (ICDAS II) as described in Table 1 . Each root surface was assigned two codes. The threshold applied to define a root surface as carious in this study was a Code 2 caries lesion code in combination with a Code 3 caries activity code, indicating a cavitated lesion of at least 0.5 mm depth which offers no resistance to probing with a ball-ended BPE probe. Secondary caries around an existing root surface restoration was scored in the same manner as a primary carious lesion.

Table 1
Modified international caries detection and assessment system (ICDAS II).
Caries lesion code Caries activity code
M Tooth is missing M Tooth is missing
E Root surface cannot be visualised E Root surface cannot be visualised
F Root surface is filled and sound F Root surface is filled and sound
0 No discolouration or loss of contour 0 Caries free
1 Discoloured but no cavitation 1 Arrested; Smooth, shiny and hard
2 Discoloured with cavitation (≥0.5 mm) 2 Quiescent; Leathery to gentle probing
3 Active; No resistance to gentle probing

Statistical analyses

Data from case report forms were entered into SPSS (version 22; SPSS, Inc., an IBM Company, Chicago, IL, USA) software. Fifteen participants were re-examined one week after initial exam. Intra-examiner reproducibility at root surface level was measured by the kappa statistic which was 0.95 for root caries detection indicating high rater reliability. DMFT scores were calculated from a maximum of 32 teeth. Decayed and filled root surfaces (RDFS) was calculated by adding the number of decayed and the number of filled root surfaces. A filled root surface which had secondary decay was categorised as a decayed root surface. Root caries index (RCI) was calculated as follows, [(number of decayed root surfaces) + (number of filled root surfaces)]/(total number of sound and decayed exposed root surfaces) × 100 . The data were described in bivariate tables. Normality was assessed by histograms, normal Q–Q plots, skewness values and their standard errors. For normally distributed data or normally distributed transformed data compartisons were made using a tw-sample t -test. Otherwise the non-parametric tests Mann Whitney U or Kruskal-Wallis were performed. P -values less than 0.05 were considered statistically significant.

Univariate and multivariate logistic regression analyses with the proportion of individuals with root caries experience (filled root surfaces or active root caries lesions) as the dependent variable were undertaken. This variable was dichotomized; subjects with RDFS > 0 were given a value of 1, and those with an RDFS = 0 were given a value of 0. The independent variables included were age, gender, final level of education, ASA category, alcohol consumption, smoking, fluoridated water supply, denture wearing, dental attendance, plaque control, tooth brushing frequency, interdental cleaning, periodontal disease, xerostomia, saliva buffering capacity, strep mutans count, lactobacilli count, number of teeth with coronal decay, number of missing teeth, number of teeth with coronal restoration, and number of exposed root surfaces. The continuous variables (number of teeth with coronal decay, number of missing teeth, number of teeth with coronal restorations, and number of exposed root surfaces) were dichotomized using the last quartile of the frequency distribution of that variable as the cut-off point. This reduced the continuous variables (which were recorded as a numerical value) into categorical variables to facilitate entry into the regression analyses.

The final model was chosen based on the backward elimination process, starting with the full independent variables, followed by subsequent removing of nonsignificant individual independent variables until no other nonsignificant independent variable could be removed.

Results

The characteristics of study participants are summarized in Table 2 . 334 independently living dentate older adults participated in this study. 148 (44.3%) were male and 186 (55.7%) were female. The median age was 68 (IQR 66, 72) years. 136 (40.7%) were denture wearers and 24 (7.2%) were xerostomic. The percentage of the cohort with any root caries experience (filled or decayed) was 53.3% and 25.7% had two or more carious root lesions. The median number of exposed root surfaces was 20 (IQR 28, 37). The median RCI was 3.13 (IQR 0.00, 13.92). The distribution of RCI was highly skewed as shown in Fig. 1 .

Table 2
Characteristics of study participants (N = 334).
Variable Category n %
Gender Male 148 44.3
Female 186 55.7
Denture wearing Yes 136 40.7
No 198 59.3
Xerostomia Yes 24 7.2
No 310 92.8
ASA category ASA 1 108 32.3
ASA 2 146 43.7
ASA 3 80 24.0
Level of education Primary Level 39 11.7
Second Level 143 42.8
Third Level 152 45.5
Alcohol consumption None 109 32.6
Less than 10 units/week 182 54.5
More than 10 units/week 43 12.9
Smoking status Smoker 58 17.4
Past smoker 92 27.5
Never smoked 184 55.1
Fluoridated water Yes 231 69.2
No 90 26.9
Unsure 13 3.9
Interdental cleaning Never 239 71.6
Occasionally 60 18.0
Daily 35 10.5
Frequency of brushing Less than once a day 105 31.4
At least once a day 229 68.6
Dental attendance Regular attender 153 45.8
Irregular attender 181 54.2
Periodontal condition No periodontal disease 141 42.2
Periodontal disease 193 57.8
Plaque control Good oral hygiene 136 40.7
Fair oral hygiene 118 35.3
Poor oral hygiene 80 24.0
Lactobacilli count High 172 51.5
Low 162 48.5
S. mutans count High 190 56.9
Low 144 43.1
Saliva buffering capacity Low 54 16.2
Medium 150 44.9
High 130 38.9
Continuous variables Median (IQR) Mean (SD)
Age 68 (66,72) 69.11 (4.26)
Decayed Missing Filled Teeth (DMFT) 24 (20, 27) 23.45 (4.99)
Number of missing teeth 10 (8, 16) 12.01 (6.06)
Exposed root surfaces 28 (20, 37) 29.72 (14.89)
Root Decayed Filled Surfaces (RDFS) 1.00 (0.00, 4.25) 3.35 (5.70)
Root Caries Index (RCI) 3.12 (0.00, 13.92) 9.50 (14.78)
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Jun 19, 2018 | Posted by in General Dentistry | Comments Off on Risk indicators associated with root caries in independently living older adults
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