Abstract
Objective
The objective of this study was to describe oral health literacy (OHL) among periodontal patients and to examine its association with periodontal health status.
Methods
This cross-sectional study included new and referred patients presenting to the University of North Carolina Graduate Periodontology Clinic. Sociodemographic and dental history information were collected. OHL was measured using a dental word recognition instrument, Rapid Estimate of Adult Literacy-30 (REALD-30). Clinical periodontal examinations were completed.
Results
One hundred and twenty-eight participants enrolled and 121 completed all study examinations and instruments. Despite a high level of education among participants in our study, low levels of OHL were found in one-third (33 percent) of the study population. Thirty-one percent had moderate OHL (score of 22–25), 37 percent had high OHL (score ≥ 26). The mean REALD-30 score was 23. Fifty-three percent of participants had severe periodontitis, 29 percent had moderate periodontitis, and 18 percent had mild or no periodontitis. Bivariate analysis showed a significant association between OHL and periodontal status (P < 0.05). The effect of OHL on periodontal health status remained statistically significant (P < 0.002) even after controlling for smoking, race, and dental insurance.
Conclusion
Lower OHL was associated with more severe periodontal disease among new and referred patients presenting to the University of North Carolina Graduate Periodontology Clinics.
Keywords: oral health, literacy, health literacy, periodontitis, periodontal disease
Introduction
Health literacy includes the ability to understand instructions on prescription drug bottles, appointment slips, medical education brochures, doctor’s directions and consent forms, and the ability to negotiate complex health-care systems. The 2006 National Assessment of Adult Literacy survey indicated that 43 percent of the adult population have limited health literacy skills and have difficulty understanding basic health information (1). Research in medical settings demonstrates the importance of literacy for patient adherence to medical instructions and increased positive health outcomes. Low health literacy is associated with worse health and less understanding of prevention, maintenance, and self-care instruction and advice (2). These skills are particularly critical in the management of chronic diseases (3,4).
Until recently oral health literacy has been largely ignored, but it is a priority for future research (5,6). Oral health literacy is the degree to which individuals have the capacity to obtain, process, and understand basic oral health information and services needed to make appropriate health decisions (6). Limited literacy skills among adults are widespread and are hypothesized to have a large effect on oral health disparities, creating a barrier to achieving better oral health outcomes (6,7).
Oral health literacy levels among dental patient populations can be estimated with the previously validated Rapid Estimate of Adult Literacy in Dentistry (REALD-30) (8). In a study assessing oral health literacy among adult general dental patients,it was found that those with incorrect knowledge of dental questions and fair/poor oral health status had greater odds of having a low literacy level than those with correct knowledge (7).
Periodontal disease is a widespread chronic inflammatory dental disease with potential for systemic health implications. Patients may present with a reversible condition: gingivitis, or an irreversible condition: periodontitis. This study focuses on patients with periodontitis as defined by the Centers for Disease Control and Prevention (CDC) (9). The American Academy of Periodontology estimates that about 50 percent of adults age 55–64 have at least one tooth with moderate to severe periodontal disease (10). Research indicates that complex relationships exist between periodontal disease and cardiovascular disease, pulmonary disease, diabetes, stroke, and preterm low birth weight (11). Management of this disease requires detailed understanding of complex self-care regimens as well as strict adherence to recall intervals; aspects of care which are likely related to oral health literacy. Studies have established that periodontal disease can be effectively treated and stabilized over time with sustained patient compliance (12). In addition, it has been consistently illustrated that there is an association between the presence of periodontal disease and decreased oral health-related quality of life (13–16).
Designing a program to address the patient’s oral health literacy (from both the provider’s and the patient’s perspectives) may be important, but to date has not been routinely incorporated in management of periodontal disease.
To our knowledge, this is the first study to evaluate oral health literacy levels and the prevalence and severity of periodontal disease.
Methods
Sample and data collection
A convenience sample of participants was recruited from patients presenting for an initial consultation appointment to the University of North Carolina Graduate Periodontology Clinic. Written informed consent and Health Insurance Portability and Accountability Act (HIPAA) consent forms were obtained for study participation. The study was approved by the Biomedical Institutional Review Board at the University of North Carolina. All subjects met the following inclusion criteria: a) 18 years of age or older; b) English speaking (REALD-30 has been validated in adult English-speaking populations only); and c) new or referred patients to the clinic (in an effort to reduce any potential confounding effects of repeated interactions in a periodontal clinic setting).
Oral health literacy assessment
Oral health literacy was measured using the REALD-30 (8). This previously validated (Cronbach’s α = 0.87) instrument includes 30 dental-related words arranged in order of increasing difficulty. Words were read aloud by the subject to the interviewer. Because REALD-30 is a word recognition test, participants were asked not to try to phonetically deduce the words, but rather to skip a word if they did not know it. One point is given to each word pronounced correctly and an overall score between 0 (lowest literacy) to 30 (highest literacy) is generated. The REALD-30 score was categorized as low (≤21), moderate (22 to 25), or high (≥26).
Two interviewers were trained and calibrated in the interview and survey methods. To promote consistent and correct interview techniques, interviewers were also provided with an instructional manual (containing the data collection protocol, consent and HIPAA forms, and survey questions). If the subject experienced difficulty reading the consent or HIPAA waiver forms, the interviewer read them aloud.
In addition to the REALD-30, each patient completed questionnaires regarding oral health knowledge and oral health behavior. Five true/false response questions were asked to assess dental knowledge and the respondents were given one point for each correct response to create a knowledge score: a) “It is normal to have bleeding of the gums while brushing or flossing your teeth”; b) “Plaque causes gum disease if not cleaned from the teeth and gums”; c) “Having persistent bad breath is a symptom of gum disease”; d) “Pus between the gum and a tooth is common in healthy gums”; and e) “Teeth can become loose and move if you have gum disease.” The oral health behavior component consisted of six categorical questions on oral hygiene and dental habits including: smoking habits, brushing frequency, flossing frequency, rinse frequency, and toothpaste use. Additionally, sociodemographic questions were examined as exploratory covariates. Sociodemographic data collected included race, ethnicity, gender, marital status, education, age, annual family income, home ownership, amount of previous dental exposure, dental insurance status, and smoking status.
Clinical assessment
Following the interview, a periodontal examination was completed by one of five trained and calibrated examiners who were blinded to the results of the oral health literacy evaluation.
Clinical periodontal parameters were measured using a manual UNC-15 periodontal probe (Hu-Friedy Manufacturing, Chicago, IL, USA) at six sites per tooth (i.e., mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual). The clinical parameters recorded included the following: probing depth (PD): distance from the gingival margin to base of the sulcus or pocket; clinical attachment loss (CAL): distance from the cementoenamel junction to the base of the sulcus or pocket.
Periodontal health status was determined based on extent and severity of periodontal disease using the CDC case definition of periodontal disease (9) that defines disease as following: Severe Periodontitis: ≥2 interproximal sites with CAL ≥6 mm (on more than one tooth) and ≥1 interproximal site with PD ≥5 mm; Moderate Periodontitis: ≥2 interproximal sites with CAL ≥4 mm (on more than one tooth) or ≥2 interproximal sites with PD ≥5 mm (on more than one tooth); Health or Mild Periodontitis: neither “moderate” nor “severe” periodontitis (9).
Prior to the conduct of this study, a training exercise with a gold standard examiner was conducted to standardize measurement techniques and quantitate variability within and between examiners. Percent agreement with the gold standard was >90 percent for PD and CAL measurements, and Kappa scores were >0.90.
Data analysis
The purpose of this study was to address the relationship between oral health literacy and periodontal health status in a convenience sample of patients presenting to the University of North Carolina Graduate Periodontology Clinics. The outcome variable was periodontal health status, as defined by the CDC (9) and coded as Severe Periodontitis = 1; Moderate Periodontitis = 2; Health or Mild Periodontitis = 3.
The primary explanatory variable was the REALD-30. Additional variables considered as covariates included race (Caucasian/non-Caucasian); education (≤high school/ ≥ college); dental insurance (yes/no); smoking (current or former smoker/never smoked); family history of periodontal diseases (yes/no); age; and sum of oral health knowledge questionnaire items.
Statistical analysis was performed using SAS 9.2 (SAS Institute, Inc., Cary, NC, USA). Exploratory univariate analyses were performed to examine distributions of data and to inspect for outliers or missing data. Bivariate analysis was then performed to investigate associations between patient characteristics and periodontal health status using Mantel-Haenszel analysis.
A proportional odds model using forward selection was generated for periodontal disease status. REALD-30 score, age in years, and patient characteristics were included in the model as possible explanatory variables. For the noncontinuous variables, the reference groups defined in the model were Caucasian, 4-year college degree or more, no dental insurance, never smoked, low dental knowledge, and a positive family history of periodontal disease. Level of significance was set at 0.05.
Results
One hundred and twenty-one subjects were included in this cross-sectional study. Previous studies using the REALD-30 established the minimum sample size of 102 to detect enough power at α = 0.05 (7,17).
Among the 121 subjects recruited for the study (Table 1), slightly more than half of the participants were female (51 percent) and the majority were Caucasian (74 percent). The average age of participants was 54 years [standard deviation (SD) 13.6]. Less than half (44 percent) of subjects had dental insurance. The majority of those with insurance were covered by private insurance (81 percent). A large portion of subjects (45 percent) had at least a 4-year college degree.
Table 1.
Sociodemographic Characteristics
| Total* | Frequency | Mean (SD) or percent (%) |
|
|---|---|---|---|
| Sex | 118 | ||
| Male | 58 | 49 | |
| Female | 60 | 51 | |
| Age (years) | 121 | 54 (13.6) | |
| Race | 120 | ||
| White | 90 | 74 | |
| Black/African American | 20 | 17 | |
| Hispanic/Latino | 3 | 2 | |
| Native American | 1 | 1 | |
| Asian | 6 | 5 | |
| Dental insurance | 119 | ||
| Yes | 52 | 44 | |
| No | 67 | 56 | |
| Type of dental insurance | 43 | ||
| Medicaid | 4 | 9 | |
| Private | 35 | 81 | |
| Other | 4 | 9 | |
| Education level | 119 | ||
| Some high school or less | 3 | 3 | |
| High school graduate or GED | 19 | 16 | |
| Some college or technical degree | 44 | 37 | |
| 4-year college degree or more | 53 | 45 | |
| Marital status | 118 | ||
| Married | 71 | 60 | |
| Separated/divorced | 25 | 21 | |
| Never married or single | 13 | 11 | |
| Other | 9 | 8 | |
| Annual income | 114 | ||
| Less than $10,000 | 14 | 12 | |
| $10,000 to $29,999 | 30 | 26 | |
| $30,000 to $49,999 | 31 | 27 | |
| $50,000 to $69,999 | 14 | 12 | |
| $70,000 to $89,999 | 13 | 11 | |
| $90,000 or more | 12 | 11 | |
| Home ownership | 109 | ||
| Yes | 83 | 76 | |
| No | 26 | 24 |
Not all items were answered by every enrolled subject.
GED, general equivalency diploma; SD, standard deviation.
Most subjects presented to the University of North Carolina Graduate Periodontology Clinic for comprehensive periodontal treatment (73 percent), with the remainder referred for prescription procedures (i.e., clinical crown lengthening, dental implant placement, gingival grafting) (Table 2). Only 13 percent of subjects reported being current smokers, but a large portion reported being former smokers (45 percent). Less than half of subjects (42 percent) reported having never smoked. Very few patients reported having diabetes (5 percent).
Table 2.
Dental Characteristics
| Total* | Frequency | Percent (%) |
|
|---|---|---|---|
| Reason for clinic visit | 117 | ||
| Comprehensive periodontal treatment | 85 | 73 | |
| Prescription procedure | 32 | 27 | |
| Previous dental care | 110 | ||
| 1–4 restorations/procedures | 53 | 48 | |
| 5 or more restorations/procedures | 57 | 52 | |
| Time since last dental checkup/cleaning | 120 | ||
| More than 2 years | 10 | 8 | |
| 1 to 2 years | 8 | 7 | |
| Less than 1 year | 102 | 85 | |
| Frequency of brushing teeth | 121 | ||
| Once/twice a week | 4 | 3 | |
| Once a day | 26 | 21 | |
| More than once a day | 91 | 75 | |
| Frequency of flossing teeth | 121 | ||
| Never | 1 | 1 | |
| Hardly ever | 12 | 10 | |
| Once/twice a week | 32 | 26 | |
| Once a day | 52 | 43 | |
| More than once a day | 24 | 20 | |
| Use mouth rinse | 121 | ||
| Yes | 91 | 75 | |
| No | 28 | 23 | |
| Don’t know | 2 | 2 | |
| Family history of periodontal disease | 118 | ||
| Yes | 24 | 20 | |
| No | 94 | 80 | |
| Cigarette smoking | 121 | ||
| Current smoker | 16 | 13 | |
| Former smoker | 54 | 45 | |
| Never smoked | 51 | 42 | |
| Diabetes | 121 | ||
| Yes | 6 | 5 | |
| No | 115 | 95 |
Not all items were answered by every enrolled subject.
Results from the behavior survey showed, as expected for a predominantly referral based specialty, that the majority of subjects had recently been to the dentist (85 percent). Subjects reported a variety of dental behaviors and frequencies of visits (Table 2).
Results from the REALD-30 were relatively evenly distributed among the three categories, with 33 percent scoring 21 or less (low oral health literacy), 31 percent scoring 22–25 (moderate oral health literacy), and 37 percent scoring 26 or greater (high oral health literacy). The mean score was 23 (SD 4.31).
Of the participants, more than half of the subjects had severe periodontal disease (53 percent) with 29 percent having moderate periodontitis and 18 percent having mild or no periodontal disease. Bivariate comparisons (Table 3) suggest that race, smoking, and categorized REALD-30 were all significantly associated (P < 0.05) with periodontal health status (health/mild, moderate, severe), while education, family history, and insurance status were not. Age was examined in our bivariate analysis but not included in Table 3 as it was linear and not a categorical variable as were the other measures presented. We used a Cochran–Mantel–Haenszel statistical test to examine age and found no significant association with periodontal disease.
Table 3.
Percent Distribution and Periodontal Disease Severity by Predictor Variables
| Percent distribution |
P-value* | ||||
|---|---|---|---|---|---|
| Overall |
Healthy/mild |
Moderate |
Severe |
||
| (possible n = 121) | (n = 22) | (n = 35) | (n = 64) | ||
| Race | |||||
| White/Caucasian | 75 | 86 | 89 | 63 | 0.004 |
| Non-White/minority | 25 | 14 | 11 | 37 | |
| Education | |||||
| High School or less | 18 | 14 | 9 | 25 | 0.072 |
| Some college or more | 82 | 86 | 91 | 75 | |
| Dental insurance | |||||
| No | 56 | 50 | 53 | 60 | 0.340 |
| Yes | 44 | 50 | 47 | 40 | |
| Smoking | |||||
| Never | 42 | 59 | 57 | 28 | 0.001 |
| Current or former | 58 | 41 | 43 | 72 | |
| Family history of periodontal disease | |||||
| No | 80 | 77 | 86 | 77 | 0.652 |
| Yes | 20 | 23 | 14 | 23 | |
| Dental knowledge | |||||
| Low (≤50% correct) | 14 | 5 | 14 | 17 | 0.715† |
| Moderate (>50% correct) | 26 | 32 | 29 | 22 | |
| High (100% correct) | 60 | 64 | 57 | 61 | |
| Categorized REALD-30 | |||||
| Low (<22) | 33 | 14 | 20 | 47 | <0.001† |
| Moderate (22–25) | 31 | 32 | 37 | 27 | |
| High (26–30) | 36 | 55 | 43 | 27 | |
Based on Mantel–Haenszel Mean Score Statistics with standardized midrank scores, unless otherwise noted.
Mantel–Haenszel Nonzero Correction Statistics with standardized midrank scores.
REALD-30, Rapid Estimate of Adult Literacy-30.
Figure 1 shows the relationship between oral health literacy and periodontal health status.Among subjects with low oral health literacy, 75 percent (n = 30) had severe disease, while among subjects with high oral health literacy, only 39 percent (n = 17) had severe disease. Conversely, among subjects with low oral health literacy, only 8 percent (n = 3) demonstrated health/mild disease, while among subjects with high oral health literacy, 27 percent (n = 12) demonstrated health/mild disease.
Figure 1.
Periodontal health status by oral health literacy category.
Table 4 reports the odds ratio (OR), confidence intervals, and P-values for the proportional odds model for periodontal disease severity. REALD-30 score (continuous), race, dental insurance, and smoking were included in the final model for periodontal health status using forward variable selection. The adjusted OR for REALD-30 score was 0.84 (P = 0.002); meaning that higher literacy scores were “protective.” For consistency in interpretation, we calculated the inverse (1/0.84) to get an OR > 1. In other words, if health literacy score decreases one unit (decrease in oral health literacy level), then the likelihood of having worse periodontal disease is 1.19 times more likely when adjusted for race, dental insurance, and smoking status (P = 0.002). Compared with Caucasians, non-Caucasians were 5.00 times more likely to have worse periodontal disease status adjusting for other variables (P = 0.006) and compared with people who have dental insurance, people without dental insurance were 2.32 times more likely to have worse periodontal disease status adjusting for other variables (P = 0.043). Smokers were 3.86 times more likely to have worse periodontal disease status adjusting for other variables (P= 0.001) when compared with nonsmokers.
Table 4.
Proportional Odds Model for Oral Health Literacy and Periodontal Disease Status*
| OR* | 95% C.I. | P-value | |
|---|---|---|---|
| REALD-30 score (0–30) | 1.19 | (1.06, 1.33) | 0.002 |
| Race (Non-Caucasian versus Caucasian) | 5.00 | (1.60, 15.61) | 0.006 |
| Dental insurance (No versus Yes) | 2.32 | (1.03, 5.22) | 0.043 |
| Smoking (Yes versus No) | 3.86 | (1.73, 8.61) | 0.001 |
Odds of worse periodontal disease status.
CI, confidence intervals; OR, odds ratio; REALD-30, Rapid Estimate of Adult Literacy-30.
Discussion
To our knowledge this was the first study to examine the association between oral health literacy and periodontal health status. Although recent studies have highlighted the importance of oral health literacy as it relates to a patient’s oral health, they have not focused specifically on periodontal health status. It has been demonstrated that there is an association between health literacy and chronic disease control. For example, diabetic patients with inadequate health literacy are 2.03 times more likely to have poor glycemic control (HbA1c ≥ 9.5) and 2.33 times as likely to have retinopathy (3). In another study, 92 percent of patients with an adequate level of health literacy knew that a blood pressure of 160/ 100 mmHg is high, but only 55 percent of patients with an inadequate level of health literacy knew this (18). Periodontal disease is similarly chronic in nature; patient understanding and compliance are essential for successful long-term maintenance and periodontal stability (19,20). The results of this study indicated that race, smoking, and oral health literacy were significantly associated (P < 0.05) with periodontal health status (health/mild, moderate, severe). A surprising finding from our study was that education, family history, and insurance status were not found to be associated with periodontal health status despite the fact that these factors have been cited as predictors of periodontal disease in other populations (21–23). In our sample, over 80 percent had more than a college education, had no family history of periodontal disease and had private insurance. Our relatively small sample size may have resulted in this limited variation in this study.
This study did not find an association between knowledge and having periodontal disease. Several reasons may explain this discrepancy. First, there is not currently a validated measure for periodontal knowledge applicable to this study. Thus, the knowledge questions likely did not capture all important items needed to completely measure knowledge. Second, a few literacy conceptual models consider knowledge to be part of literacy; others think of it as a separate part of an individual’s capacity to understand and use health information. Knowledge about disease often does not translate into the practice of the behaviors that are needed to manage the disease. Literacy encompasses a set of skills that includes accessing, processing, and acting on information to manage health.
These findings must take into consideration the limitations of the study.This study was cross-sectional and therefore does not lead to casual inferences. Eighty-five percent of the subjects reported being seen by a dentist within the last year. A high percentage of participants reported brushing, flossing, and rinsing, which suggests previous education regarding plaque control. This may have led to increased oral health literacy among the study population. The population sample in the present study was a convenience sample and may not be representative of the general population, or of those attending a general dentist’s practice. Due to the sample size, we were unable to examine the existence of effect modification. This should be considered in future studies. It is also important to understand the limitations of the REALD-30. It is a word recognition test and does not measure reading comprehension. Therefore it is not a comprehensive dental health literacy instrument, although it does show a strong association with reading comprehension (8). Finally, while examiners in this study were calibrated, variations in examination technique could have occurred among the multiple examiners in the study.
Oral health literacy has been examined among various populations. Similar to our results, Jones et al. (7) found about one-third of the subjects fell into the low literacy category (REALD-30 score <22). In an indigenous Australian population it was found that lower oral health literacy was significantly associated with decreased dental knowledge and more harmful oral-health-related behavior (24).
Results from the current study demonstrate that as oral health literacy scores (sum of REALD-30) decreased by one unit, the likelihood of having worse periodontal disease was 1.19 times (P = 0.002). Thus, if the REALD-30 score decreased by two points the patient was approximately 2.5 times more likely to have worse periodontal disease. Interestingly, level of education was not significantly associated with periodontal health status (P = 0.39) in the multivariate model although it was in the bivariate analysis. Other studies have found an association between periodontal health status and education (25). Using National Health and Nutrition Examination Survey (NHANES) III data, Borrell et al. (25) found that compared with those with more than a high school education, those with less than a high school education were twice (1.48 to 2.89) as likely to have periodontitis. The discrepancy of the Borrell study versus ours may be due to the very high level of education present among our subjects. Eighty-two percent of the sample reported having completed some college or higher, while only 44 percent of the NHANES III population had this level of education. Interestingly, despite the high level of education among participants in our study, low levels of oral health literacy were found in one-third (33 percent) of the study population. Similar to the NHANES III study and many other epidemio-logic reports, our study also found that race was significantly associated with periodontal health (25,26).
The findings of the present study reinforce the need for effective communication between dental health-care providers and patients regarding their periodontal disease condition. A 2005 report on the role of literacy in oral health notes that many health practitioners are not adequately prepared to address literacy needs of their patients (5). Furthermore, they point out that patients may not be aware of their own low literacy. Education level may not necessarily be related to oral health literacy level.Among adults who score in the lowest literacy category, 71 percent describe themselves as having no difficulty with reading or writing (27). Due to the chronic nature of periodontal diseases and the importance of an effective maintenance program, it is imperative that the patient has an understanding of the risk factors and etiologic factors related to periodontal disease. The patient must be equipped to adequately control the modifiable factors to reach and maintain a level of periodontal stability and health. Recommendations for overcoming low literacy barriers in nursing and medicine include assessing readability of informed consent, patient education, and other documents, including literacy issues in patient documentation, creating simple graphic descriptions of information, and using instruments or methods to identify patients with low literacy (28). Further studies are needed to assess effective methods to improve provider communication and patient understanding in the oral health care setting.
Many opportunities exist for further research examining the relationship between oral health literacy and periodontal disease status. Our study population was limited to patients seeking treatment at the University of North Carolina Graduate Periodontology Clinic. It would be beneficial to extend the study population to include patients in various clinical settings including community health centers and private dental practices. This would not only increase the sample size but also allow for greater potential variation (i.e., socioeconomic status, education level, periodontal disease status) among subjects and less bias toward having periodontal disease. A recent national survey of dentists’ communication styles found that most dentists do not routinely utilize communication techniques thought to be most effective with patients with low literacy skills (29). It would be valuable to perform a prospective study evaluating oral health and the effectiveness of various communication and education methods aimed at increasing a subject’s oral health literacy.
In conclusion, this study demonstrated a significant association between oral health literacy and periodontal health status among patients presenting to the University of North Carolina Graduate Periodontology Clinic. Dental providers should identify patients who are having difficulty using periodontal health information and assist them in better acting on the information by using effective patient communication techniques and reinforcing positive oral health behaviors. Research is needed to establish a causal relationship between oral health literacy and periodontal health status and to identify mechanisms so that inventions can be developed.
Acknowledgments
This study was supported by Award Number UL1RR025747 from the National Center for Research Resources and by Grant # RO1DE018045 from the National Institute of Dental and Craniofacial Research.
References
- 1.Kutner M, Greenberg E, Baer J. The health literacy of America’s adults: results from the 2003 National Assessment of Adult Literacy. Washington, D.C.: U.S. Department of Education, National Center for Education Statistics; 2006. [Google Scholar]
- 2.Dewalt DA, Berkman ND, Sheridan S, Lohr KN, Pignone MP. Literacy and health outcomes: a systematic review of the literature. J Gen Intern Med. 2004;19(12):1228–1239. doi: 10.1111/j.1525-1497.2004.40153.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Schillinger D, Grumbach K, Piette J, Wang F, Osmond D, Daher C, Palacios J, Sullivan GD, Bindman AB. Association of health literacy with diabetes outcomes. JAMA. 2002;288(4):475–482. doi: 10.1001/jama.288.4.475. [DOI] [PubMed] [Google Scholar]
- 4.Villaire M, Mayer G. Low health literacy: the impact on chronic illness management. Prof Case Manag. 2007;12(4):213–216. doi: 10.1097/01.PCAMA.0000282907.98166.93. quiz 7–8. [DOI] [PubMed] [Google Scholar]
- 5.National institute of Dental and Craniofacial Research, National Institute of Health, U.S. Public Health Service, Department of Health Human Services. The invisible barrier: literacy and its relationship with oral health. A report of a workgroup sponsored by the National Institute of Dental and Craniofacial Research, National Institute of Health, U.S. Public Health Service, Department of Health and Human Services. J Public Health Dent. 2005;65(3):174–182. doi: 10.1111/j.1752-7325.2005.tb02808.x. [DOI] [PubMed] [Google Scholar]
- 6.U.S. Department of Health and Human Services. A national call to action to promote oral health. Rockville (MD): U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institutes of Health, National Institute of Dental and Craniofacial Research; 2003. [Google Scholar]
- 7.Jones M, Lee JY, Rozier RG. Oral health literacy among adult patients seeking dental care. J Am Dent Assoc. 2007;138(9):1199–1208. doi: 10.14219/jada.archive.2007.0344. quiz 266-7. [DOI] [PubMed] [Google Scholar]
- 8.Lee JY, Rozier RG, Lee SY, Bender D, Ruiz RE. Development of a word recognition instrument to test health literacy in dentistry: the REALD-30 - a brief communication. J Public Health Dent. 2007;67(2):94–98. doi: 10.1111/j.1752-7325.2007.00021.x. [DOI] [PubMed] [Google Scholar]
- 9.Page RC, Eke PI. Case definitions for use in population-based surveillance of periodontitis. J Periodontol. 2007;78(7 Suppl):1387–1399. doi: 10.1902/jop.2007.060264. [DOI] [PubMed] [Google Scholar]
- 10.Burt B. Position paper: epidemiology of periodontal diseases. J Periodontol. 2005;76(8):1406–1419. doi: 10.1902/jop.2005.76.8.1406. [DOI] [PubMed] [Google Scholar]
- 11.Oral health in America: a report of the Surgeon General. J Calif Dent Assoc. 2000;28(9):685–695. [PubMed] [Google Scholar]
- 12.Hirschfeld L, Wasserman B. A long-term survey of tooth loss in 600 treated periodontal patients. J Periodontol. 1978;49(5):225–237. doi: 10.1902/jop.1978.49.5.225. [DOI] [PubMed] [Google Scholar]
- 13.Cunha-Cruz J, Hujoel PP, Kressin NR. Oral health-related quality of life of periodontal patients. J Periodontal Res. 2007;42(2):169–176. doi: 10.1111/j.1600-0765.2006.00930.x. [DOI] [PubMed] [Google Scholar]
- 14.Ng SK, Leung WK. Oral health-related quality of life and periodontal status. Community Dent Oral Epidemiol. 2006;34(2):114–122. doi: 10.1111/j.1600-0528.2006.00267.x. [DOI] [PubMed] [Google Scholar]
- 15.Needleman I, McGrath C, Floyd P, Biddle A. Impact of oral health on the life quality of periodontal patients. J Clin Periodontol. 2004;31(6):454–457. doi: 10.1111/j.1600-051X.2004.00498.x. [DOI] [PubMed] [Google Scholar]
- 16.Cunha-Cruz J. Pain and discomfort are the main symptoms affecting the quality of life in periodontal disease. J Evid Based Dent Pract. 2008;8(2):101–102. doi: 10.1016/j.jebdp.2008.03.009. [DOI] [PubMed] [Google Scholar]
- 17.Miller E, Lee JY, DeWalt DA, Vann WF., Jr Impact of caregiver literacy on children’s oral health outcomes. Pediatrics. 2010;126(1):107–114. doi: 10.1542/peds.2009-2887. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Williams MV, Baker DW, Parker RM, Nurss JR. Relationship of functional health literacy to patients’ knowledge of their chronic diseaseA study of patients with hypertension and diabetes. Arch Intern Med. 1998;158(2):166–172. doi: 10.1001/archinte.158.2.166. [DOI] [PubMed] [Google Scholar]
- 19.Wilson TG., Jr How patient compliance to suggested oral hygiene and maintenance affect periodontal therapy. Dent Clin North Am. 1998;42(2):389–403. [PubMed] [Google Scholar]
- 20.Costa FO, Miranda Cota LO, Pereira Lages EJ, Medeiros Lorentz TC, Soares Dutra Oliveira AM, Dutra Oliveira PA, Costa JE. Progression of periodontitis in a sample of regular and irregular compliers under maintenance therapy: a 3-year follow-up study. J Periodontol. 2011;82(9):1279–1287. doi: 10.1902/jop.2011.100664. [DOI] [PubMed] [Google Scholar]
- 21.Michalowicz BS, Diehl SR, Gunsolley JC, Sparks BS, Brooks CN, Koertge TE, Califano JV, Burmeister JA, Schenkein HA. Evidence of a substantial genetic basis for risk of adult periodontitis. J Periodontol. 2000;71(11):1699–1707. doi: 10.1902/jop.2000.71.11.1699. [DOI] [PubMed] [Google Scholar]
- 22.Marlow NM, Slate EH, Bandyopadhyay D, Fernandes JK, Leite RS. Health insurance status is associated with periodontal disease progression among Gullah African-Americans with type 2 diabetes mellitus. J Public Health Dent. 2011;71(2):143–151. doi: 10.1111/j.1752-7325.2011.00243.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Siukosaari P, Ajwani S, Ainamo A, Wolf J, Narhi T. Periodontal health status in the elderly with different levels of education: a 5-year follow-up study. Gerodontology. 2012;29(2):e170–e178. doi: 10.1111/j.1741-2358.2010.00437.x. [DOI] [PubMed] [Google Scholar]
- 24.Parker EJ, Jamieson LM. Associations between indigenous Australian oral health literacy and self-reported oral health outcomes. BMC Oral Health. 2010;10:3. doi: 10.1186/1472-6831-10-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Borrell LN, Burt BA, Warren RC, Neighbors HW. The role of individual and neighborhood social factors on periodontitis: the third National Health and Nutrition Examination Survey. J Periodontol. 2006;77(3):444–453. doi: 10.1902/jop.2006.050158. [DOI] [PubMed] [Google Scholar]
- 26.Douglass CW, Gillings D, Sollecito W, Gammon M. National trends in the prevalence and severity of the periodontal diseases. J Am Dent Assoc. 1983;107(3):403–412. doi: 10.14219/jada.archive.1983.0273. [DOI] [PubMed] [Google Scholar]
- 27.Kirsch IS. Adult literacy in America: a first look at the results of the National Adult Literacy Survey. Washington, D.C: Office of Educational Research and Improvement, U.S. Dept. of Education; 1993. United States, Office of Educational Research and Improvement, Educational Testing Service, National Center for Education Statistics. [Google Scholar]
- 28.Horowitz AM, Kleinman DV. Oral health literacy: the new imperative to better oral health. Dent Clin North Am. 2008;52(2):333–344. doi: 10.1016/j.cden.2007.12.001. [DOI] [PubMed] [Google Scholar]
- 29.Rozier RG, Horowitz AM, Podschun G. Dentist-patient communication techniques used in the United States: the results of a national survey. J Am Dent Assoc. 2011;142(5):518–530. doi: 10.14219/jada.archive.2011.0222. [DOI] [PubMed] [Google Scholar]