Dental Students’ Opinions and Knowledge About Caries Management and Prevention

Methods

Data for this study were from a survey conducted among third-year (n=72/78) and fourth-year (n=35/77) dental students at the University of Florida College of Dentistry. A twenty-six-item, self-completed instrument consisted of questions related to the students’ attitudes and knowledge regarding caries prevention. The questionnaire was developed by the authors and was pilot-tested among ten dental school faculty members. No personal identifying information was obtained. This study was reviewed and approved by the University of Florida Health Science Center Institutional Review Board.

After one of the researchers described the survey to each of the classes before a class session in a large lecture hall, the survey questionnaires were distributed, completed, and collected. The response rate for the third-year class was 92.3 percent (72/78) and for the fourth-year class was 45.5 percent (35/77). Two follow-up attempts were made to increase the participation rate of fourth-year students, with limited success.

We solicited information on the participants’ age, gender, and plans for the first year after graduation. Students’ likelihood of using various caries management techniques after their graduation was assessed by twelve multiple-choice questions with five-point Likert-type response categories. Eighteen items were used to determine students’ knowledge and opinions about caries management and techniques. Each item consisted of a statement and five-point Likert response scale, which ranged from strongly agree to strongly disagree. These items focused on fluoride varnishes, xylitol gum, and remineralization of incipient lesions.

Respondents were asked to rank, in order of importance, six sources of professional knowledge and advice. To summarize the data, a weighted ranking score for each source was calculated as following: each first-place vote was assigned five points, second place was assigned four points, third place was assigned three points, fourth place was assigned two points, fifth place was assigned one point, and sixth place was assigned zero points. Points were multiplied by the number of votes in each ranking and were summed for each source of information.

Results

The overall response rate was 68.4 percent, with 92.3 percent for juniors and 45.5 percent for seniors. Respondents in the third-year class included thirty-two males (44.4 percent) and forty females (55.6 percent), with a mean age of 26.1±2.0 years (Table 1⇓). The fourth-year class respondents included fifteen males (42.9 percent) and twenty females (57.1 percent), with a mean age of 26.8±4.1 years.

When asked about their plans after graduation, almost one-half of the respondents planned to practice as an associate and be employed by another dentist. Only 5.6 percent of third- and 3.1 percent of fourth-year students planned to be self-employed dentists. Thirty percent of third- and 22 percent of fourth-year students planned to enroll in a residency program in a dental specialty. Approximately 13 percent of third- and 28 percent of fourth-year students planned to enter a general practice residency or advanced education in general dentistry program.

Responses on the likelihood of using different caries management techniques after graduation are shown in Table 2⇓. Eighty-three percent of respondents reported they would use chlorhexidine (CHX) rinses for caries control, and 12 percent were not sure. Almost 50 percent of the fourth-year respondents reported they would definitely use CHX rinses. Only 5 percent of respondents reported they would not use CHX rinses for their patients, and all were third-year students.

Regarding the use of salivary tests for detecting mutans streptococci and lactobacilli, 51 percent of respondents reportedly would definitely or probably use these tests, 26 percent were unsure if they would use them, and 21 percent reported they would probably not or not at all use them. Of those who were not sure, twenty-two out of twenty-eight respondents were third-year students. Of those who reported they would not use salivary testing, 31 percent said they did not know enough about it, and 40 percent thought it was not an effective method for controlling caries.

When assessing students’ likelihood of using fluoride varnishes for caries control, 92 percent of respondents reportedly would use them, and 78 percent reported they would use them regularly for adult patients. Almost 30 percent of respondents reported they would not use fluoride varnishes regularly for pediatric patients younger than five years of age (data not shown). When asked which fluoride varnish they were most likely to use regularly, almost 80 percent would choose Duraphat© fluoride varnish (Colgate Oral Pharmaceuticals, Inc.). When assessing students’ likelihood of using xylitol chewing gum or mints for caries control, almost 95 percent of students responded that they would definitely use or probably use them. Only 5 percent were not sure.

Responses to the statements regarding fluoride varnishes, xylitol, and remineralization are shown in Table 3⇓. Six percent of respondents strongly agreed and 38 percent agreed that fluoride varnishes are more effective than other fluoride methods, and 41 percent were not sure—including twenty-eight out of forty-one third-year students—while 13 percent disagreed. Forty percent of respondents were not sure whether fluoride varnishes have associated dental or medical risks. Almost 40 percent of all respondents were not sure whether fluoride varnish stains teeth permanently, and 5 percent thought that varnishes stain permanently. Almost 73 percent agreed that fluoride varnishes are effective in controlling root caries. Nearly 11 percent felt that use of fluoride varnishes is not a cost-effective way of controlling caries, and 25 percent were not sure.

Responses to the statements regarding the progression of enamel lesions are shown in Table 4⇓. Almost 30 percent of respondents agreed with the statement that most incipient lesions will progress into cavities, while 43 percent disagreed, 13 percent strongly disagreed, and 9 percent were not sure. Ten percent of respondents did not believe monitoring incipient lesions is a cost-effective way of treating caries, although 83 percent of respondents believed that it is. When asked whether their practice will use the caries management technique of monitoring and arresting enamel lesions, 95 percent agreed they would.

Students were asked whether training and practice of preventive dentistry in dental school should be increased, and 31 percent of respondents strongly agreed, 50 percent agreed, 10 percent were not sure, and 9 percent disagreed. When respondents were asked to rank in order of importance the sources of professional knowledge and advice, dental school received the highest score, followed by other dentists; professional journals, books, and newspapers; continuing education; and professional meetings and conferences (Table 5⇓). The Internet was ranked as the least important information source.

Discussion

This survey revealed that a majority of dental student respondents would use chlorhexidine rinses for caries control, which may indicate that dental school faculty recommend chlorhexidine rinses be used for caries control. It is generally accepted that chlorhexidine digluconate (CHX) remains the gold standard as an antiplaque and antigingivitis agent.² Although chlorhexidine has antimicrobial properties against mutans streptococci, its use as an anticaries agent remains more controversial.³ Emilson⁴ concluded that the most persistent reductions in mutans streptococci levels have been achieved by chlorhexidine varnishes, followed by gels and, lastly, mouthwashes. A systematic review by Caufield et al.⁵ concluded that the evidence for using chlorhexidine gels, varnishes, rinses, or a combination chlorhexidine-fluoride therapy, was “suggestive but incomplete.” Also, in the review by Twetman,³ it was concluded that there is a need for further research to evaluate the caries-preventive effect of chlorhexidine. Because of the lack of strong conclusive evidence to support the use of chlorhexidine rinses for caries control, the question remains whether chlorhexidine rinses should be recommended in evidence-based dental curricula.

This survey found that almost one-half of the respondents were not sure or would probably not use saliva tests for caries control or management. It is known that salivary tests can be used to assess cariogenic bacteria colonization, monitor caries activity, and identify individuals at high risk for caries. The determination of salivary mutans streptococci has also been found to be a good educational and motivational tool for patients.⁶ Most of the respondents who were unsure were third-year students with less experience or exposure to this topic than fourth-year students; many juniors reported that they did not know enough about salivary tests to make an assessment. However, nineteen students thought that salivary testing is not an effective tool to help in caries management. This result indicates the need to clarify the role of saliva testing in caries management of the dental curriculum.

Fluoride’s ability to inhibit or even reverse the initiation and progression of early demineralization is well documented. High-fluoride-concentration varnish was introduced in the United States in 1991,⁷ and its use by the dental community is increasing. The latest evidence-based clinical recommendations of professionally applied topical fluoride issued by the American Dental Association’s Council on Scientific Affairs⁸ concluded that fluoride varnish applied every six months is effective in preventing caries in the primary and permanent dentition of children and adolescents, and two or more applications of fluoride varnish per year are effective in preventing caries in high-risk populations. In addition, fluoride varnish applications take less time, create less patient discomfort, and achieve greater patient acceptability than topical fluoride gels, especially in preschool-aged children.

Most of the respondents in our survey reported that they would use fluoride varnishes for caries control. However, there was a high uncertainty of its efficacy compared to other fluoride methods. Also, surprisingly, many students were not aware whether fluoride varnish use has any related medical or dental risks. Many students are not aware of the fact that fluoride varnishes do not stain teeth permanently. One positive finding was that many students agreed that fluoride varnishes are effective in controlling root surface caries.

Almost 30 percent of all respondents, including a large proportion of third-year students, reportedly would not use fluoride varnishes regularly for young pediatric patients. This could be due to the students’ lack of current information about the recommendations of fluoride varnish use. Most of the respondents chose Duraphat as the primary brand to be used, perhaps due to their familiarity with it and because it is the most commonly used brand in this dental school. This finding indicates that the faculty and dental school clinical environment have a great influence on how students choose their materials in their future practices.

There is a considerable amount of evidence that the use of gum or mints containing xylitol prevents dental caries in the permanent teeth when used several times daily.⁹ The caries reduction ranged from 30 percent to 60 percent when compared to controls without the gum use. According to the NIH consensus statement on the diagnosis and management of dental caries,¹⁰ the evidence for xylitol as a primary prevention agent for dental caries is strong. The preventive effect of xylitol seems to derive from the replacement of fermentable dietary sugars and reduction of the amount of dental plaque or the amount of mutans streptococci in plaque and saliva.¹¹ When assessing students’ likelihood of using xylitol chewing gum or mints for caries control in their patients, almost all of the respondents in our survey indicated that they would use them, which indicates that students understand the beneficial effects of xylitol on oral health.

Responses to the statements regarding the progression of enamel lesions were conflicting. Respondents were almost equally divided on whether or not most incipient lesions will progress into cavities. However, most respondents believed that monitoring of early lesions is a cost-effective method of treatment. Also, most of the students reportedly will use the caries management technique of monitoring and arresting enamel lesions in their future practices. This indicates that students are familiar with the modern concept of remineralizing incipient caries lesions.

The students’ ranking of the dental school as the most important source of professional knowledge and advice indicates that students rely and depend on the information they are provided in dental school. This is an expected response from students currently enrolled in the dental school. Also, it is logical for students to rank other dentists as important sources of advice in the future. Lower rankings for professional meetings and conferences could be due to the students’ lack of exposure to professional meetings and, therefore, uncertainty about their potential informational value.

Students’ response that training and practice of preventive dentistry in the dental school should be increased may indicate that students accept modern caries management and prevention principles and that there is a need to develop the clinical dental curriculum to focus more on practice of these various techniques. Recently, the Curriculum Committee of the University of Florida College of Dentistry reviewed the education in preventive dentistry in the D.M.D. curriculum and recommended several steps to improve the content of preventive dentistry and increase the clinical prevention experiences for freshman and sophomore students. Topics on preventive dentistry are taught in several individual required courses, and the Curriculum Committee recognized the need to integrate and coordinate preventive dentistry across all four years of dental education. There are currently active efforts at this college to institute clinical oral disease prevention experiences for freshman and sophomore students.

Cariology and scientific background for caries management are also taught in several individual courses, but there is no individual cariology course per se. Most of the scientific principles are taught in the interdisciplinary course “Infectious Diseases,” which is administered by the Department of Oral Biology and offered during the summer before students’ third year and entry into clinical training. Based on this survey, there is a need to improve the content and educational experiences in cariology and preventive dentistry in this college. One of the ongoing efforts to improve the teaching experiences in preventive dentistry and caries management is the recent implementation of a comprehensive Caries Risk Assessment and Management Program in the Operative Teaching Clinic.

Because practicing dentists can play an important role in helping patients to improve their oral health, it is important that newly graduated dentists have been provided the most current and evidence-based concepts of preventive dentistry. To meet the demand for producing highly competent dental graduates, more evidence-based programs and curricula focused on caries prevention should be integrated into dental education. Such programs should stress the importance of prevention in dental students’ future practice and provide substantial hands-on instruction in the use of caries prevention techniques.

Males and females responded equally to the survey, and the results represent the opinions of both genders. However, one limitation of this study is the low response rate for seniors, mainly due to their time constraints and other responsibilities. This survey was conducted during the spring semester, which is a busy time for seniors to complete their requirements. This response level was not unexpected; other surveys have experienced similar challenges in obtaining participation by busy senior students.¹²

In conclusion, this study suggests there is a need to integrate a more comprehensive caries prevention program into the dental curriculum at the University of Florida College of Dentistry. Such a program should provide current, evidence-based information on caries prevention and experience in practical, hands-on application of caries risk management in clinical settings. Further research is needed to assess the outcome and impact of the college’s recently implemented Caries Risk Assessment and Management Program.