Objective The purposes of this study were to (1) quantify dentists' practice patterns regarding caries prevention and (2) test the hypothesis that certain dentists' characteristics are associated with these practice patterns.
Design The study used a cross-sectional study design consisting of a questionnaire survey.
Participants The study queried dentists who worked in outpatient dental practices who were affiliated with the Dental Practice-Based Research Network Japan, which seeks to engage dentists in investigating research questions and sharing experiences and expertise (n=282).
Measurement Dentists were asked about their practice patterns regarding caries preventive dentistry. Background data on patients, practice and dentist were also collected.
Results 38% of dentists (n=72) provided individualised caries prevention to more than 50% of their patients. Overall, 10% of the time in daily practice was spent on caries preventive dentistry. Dentists who provided individualised caries prevention to more than 50% of their patients spent significantly more time on preventive care and less time on removable prosthetics treatment, compared to dentists who did not provide individualised caries prevention. Additionally, they provided oral hygiene instruction, patient education, fluoride recommendations, intraoral photographs taken and diet counselling to their patients significantly more often than dentists who did not provide individualised caries prevention. Multiple logistic regression analysis suggested that the percentage of patients interested in caries prevention and the percentage of patients who received hygiene instruction, were both associated with the percentage of patients who receive individualised caries prevention.
Conclusions We identified substantial variation in dentists' practice patterns regarding preventive dentistry. Individualised caries prevention was significantly related to provision of other preventive services and to having a higher percentage of patients interested in caries prevention, but not to the dentist's belief about the effectiveness of caries risk assessment. (Clinicaltrials.gov registration number NCT01 680 848).
- ORAL MEDICINE
- PREVENTIVE MEDICINE
- PUBLIC HEALTH
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Strengths and limitations of this study
To our knowledge, this is the first study to clarify dentists' practice patterns regarding caries prevention in Japan has substantial variation in the Dental Practice-Based Research Network.
This study suggested possible reasons for the variation of practice patterns regarding caries prevention.
This study has relatively wide diversity of participants, with respondents from all seven regions in Japan. Given the cross-sectional nature of the study, causative relationships between factors and the provision of individualised caries prevention were difficult to assess.
Dental caries is a largely preventable disease,1–3 but it continues to affect 60–90% of school children and almost 100% of adults, constituting the most common chronic disease among children and adolescents.4 ,5 Oral health is essential to general health and optimal quality of life and the high prevalence of dental caries highlights the importance of public health approaches to its prevention.5 According to Zero et al6, dental caries is a dynamic dietomicrobial disease involving cycles of demineralisation and remineralisation. The early stages of this process are reversible by modifying or eliminating aetiological factors (such as plaque biofilm and diet) and increasing protective factors (such as fluoride exposure and salivary flow).6 Axelsson et al7 ,8 noted that improved self-performed oral hygiene, the daily use of fluoridated dentifrice, regularly repeated professional tooth cleanings and plaque control effectively prevented the recurrence of dental caries.7 ,8 Caries risk assessment is the first step in preventive treatment.9 Risk assessment is the determination of the person's probability of developing new carious lesions during a specific time period and the probability of a change in the size or activity of existing lesions across time.2 ,10 ,11 Our previous studies revealed that dentists' perception of each potential caries risk factor and the administration of diet counselling varied between dentists.12 ,13 However, dentists' practice patterns regarding caries prevention and factors that affect these patterns remain unclear. The recent establishment of the Dental Practice-Based Research Network Japan (JDPBRN) created an opportunity for international comparisons. JDPBRN is a consortium of dental practices with a broad representation of practice types, treatment philosophies and patient populations and it has a shared mission with the DPBRN,14 now called the National DPBRN (http://NationalDentalPBRN.org). The network regions of the JDPBRN represent all seven districts in Japan (Hokkaido, Tohoku, Kanto, Chubu, Kansai, Chugoku-Shikoku and Kyushu). The studies conducted in the USA and Japan shared the same purpose of clarifying practice patterns regarding caries diagnosis and treatment.
The purposes of this study were to (1) quantify dentists' practice patterns regarding caries preventive dentistry and (2) test the hypothesis that certain dentists' characteristics are associated with these practice patterns.
Materials and methods
We conducted a cross-sectional study consisting of a questionnaire survey, which was administered in Japan between May 2011 and February 2012.12 This study followed the World Association's Declaration of Helsinki. All participants provided written informed consent prior to participation. We used the same questionnaire that was used in the US DPBRN study ‘Assessment of Caries Diagnosis and Caries Treatment’15 and the ‘DPBRN Enrollment Questionnaire’. 16 Four dentists and clinical epidemiologists collaboratively translated these questionnaires into Japanese. The translated version of these questionnaires is available at http://www.dentalpbrn.org/uploadeddocs/Study%201(Japanese%20Version.pdf). (Original English version: http://nationaldentalpbrn.org/pdf/Study%201%20questionnaire%20FINAL%20after%20pre-testing%20021306.pdf). The questionnaires used in this study were validated by expert consultation and focus groups on potential subjects.17 Dentists were asked about their practice patterns regarding caries preventive treatment. Background data on patients, practice and participating dentists were also requested.
We queried dentists working in outpatient dental practices who were affiliated with JDPBRN (n=282). Participants who indicated that they perform restorative dentistry at their practice were recruited from the JDPBRN website and mailings.
Dentists' practice patterns regarding individualised caries preventive dentistry
Practice patterns regarding individualised caries preventive regimens were measured with the following question: for what per cent of patients do you administer individualised caries preventive treatment specifically for their needs?
Items used to measure practice patterns regarding time spent doing prevention-related care and percentage of patients who receive specific dental services
Practice patterns regarding time spent doing prevention-related care and the percentage of patients who received specific dental services was measured using the questions listed in table 1.
To identify the characteristics of the dentist, patient and practice that were associated with the use of individualised caries prevention, theoretical models were discussed and identified in accordance with previous studies.12 ,15 ,19 ,20 In addition, explanatory variables were extracted, consisting of four categories shown in table 1.
Description and comparison of practice patterns by the use of individualised caries prevention
We examined the relationship between dental practice patterns and the use of individualised caries prevention. χ2 tests were performed to assess the association between practice patterns and the use of individualised caries prevention.
The use of individualised caries prevention was categorised dichotomously: ‘less preventive’ (1–49%) and ‘more preventive’ (50–100%), according to a previous study.9 To compare our data with the US data, we calculated the mean percentages of patients who received individualised caries prevention according to a previous study.9
Factors affecting the decision to provide individualised caries prevention
Descriptive analysis was conducted through univariate regression analysis for explanatory variables associated with dentists' practice patterns of individualised caries prevention. Subsequently, multiple logistic regression analysis was conducted to examine the relationship between explanatory variables and the prevalence of patients receiving individualised caries prevention. Odds ratios (ORs) and 95% confidential intervals (CIs) were calculated. All statistical analyses were performed with STATA/SE (V.10; STATA Corporation, College Station, Texas, USA). Statistical significance was set at p<0.05.
Demographic information of participants
Questionnaires were distributed to 282 dentists and valid responses were collected from 189 (67%). The demographic characteristics of the study participants are shown in table 2.12 ,13 The mean number of years (±SD) elapsed since graduation from dental school was 18.5±9.9 and the participants were predominantly men (n=154, 82%). With regard to practice setting, 40% (n=76) of practices were established in government ordinance-designated cities of over 700 000. The percentage of dentists who performed caries risk assessment as a routine part of treatment planning was 26% (n=49). The percentage of dentists who agreed that caries risk assessment is effective was 67% (n=127).
Dentists' practice patterns according to provision of individualised caries prevention
Seventy-two participants (38%) answered that 50% or more of their patients received individualised caries prevention (ie, were ‘more preventive’). Eleven participants (6%) answered that 100% of their patients received individualised caries prevention (figure 1).
Table 3 shows the practice patterns of dental procedures and the differences of practice patterns by use of individualised caries prevention. Participants spent 29% of their time on non-implant restorative, 19% on endodontic therapy and 18% on removable prosthetics. Participants spent 10% of their time on prevention-related care. Participants who were ‘more preventive’ (n=72) spent significantly more time on preventive dentistry (p=0.0007) and less time on removable prosthetics (p=0.0159).
Table 4 shows the relation among certain procedures performed in general dental practice and the percentage of time that patients receive prevention-related care. The mean percentage of patients who receive oral hygiene instruction was 67%, while 37% received patient education from written pamphlets. Participants who were ‘more preventive’ (n=72) administered significantly more oral hygiene instruction (p<0.0001), gave written pamphlets (p<0.0001), either prescribed fluoride gels/rinses or recommended for home use (p<0.0001), had patient education available from videos or slides (p=0.0011), obtained intraoral photographs (p=0.0021), had in-office fluoride applications (p<0.0001) and provided diet counselling (p=0.0004).
Factors associated with providing individualised caries prevention
The results of multiple logistic regression analysis are shown in table 5. Two factors were significantly associated with whether or not the practitioner reported providing individualised caries prevention to 50% of patients or more. The ORs (95% CIs) were as follows: the percentage of patients interested in caries prevention, 5.81 (3.15 to 10.70); and the percentage of patients who received hygiene instruction, 1.02 (1.01 to 1.04).
Seventy-two participants (38%) answered that the percentage of patients who received individualised caries prevention was 50% or more (‘more preventive’). Overall, 10% of the time in daily practice was spent on prevention-related care. Dentists who provided individualised caries prevention to 50% or more of their patients spent significantly more time on preventive care and provided less removable prosthetics treatment than those who did not. Additionally, they provided oral hygiene instruction, patient education, fluoride recommendations and diet counselling to their patients significantly more often than dentists who provided individualised caries prevention to less than 50% of their patients. The results of the multiple logistic regression analysis suggested that several variables were associated with whether or not dentists provide individualised caries prevention to 50% or more of their patients. Specifically, the percentage of patients interested in caries prevention and the percentage of patients who received hygiene instruction were significantly associated with high percentages of patients who receive individualised caries prevention.
According to the results of the same questionnaire survey by the US DPBRN, 52% of patients received individualised caries prevention.9 ,21 The results of this study possibly suggest that dentists in the DPBRN and JDPBRN (41.3%) have similar tendencies in providing individualised caries prevention, but the proportion was lower in Japan than in the USA. Additionally, dentists spent 10% of their time on prevention-related care in this study, which was less when compared with Northern European dentists. A previous study conducted in Norway reported that the mean caries preventive treatment time was 16.6% of the total treatment time (dentists who did not treat adult patients were excluded)22 and 22% of the total time for child patients.23 In Denmark, Iceland and Norway, dental prevention consumes 18–50% of the dentist's total time in dental care for children and adolescents.24 In the USA, the average time that general practitioners spent performing preventive procedures increased from 9.4% in 1981 to 12.4% in 1993.25 The lower preventive treatment time in Japan may be due to the differences in the healthcare system between Northern Europe and Japan. In Finland in 1999, all inhabitants under the age of 19 were entitled to free comprehensive public dental care, with a utilisation rate of approximately 95%.26 However, in Japan, dental insurance systems mainly cover dental treatment,27 so that the percentage of time spent on preventive treatment might be restricted due to economic reasons. In addition, dentists' perception regarding prevention could be one of the reasons that explain variations in preventive practice in this population. Taylor-Gooby et al28 pointed out that professional values for preventive care affect practice patterns of preventive dentistry and that British dentists valued a restorative paradigm as opposed to a preventive paradigm which devalued traditional restorative skills in a context of ‘continuing care’ payment in 1990s. Also Fox29 reviewed dentists' perceptions of prevention and its application in practice and highlighted that recently, most dentists regarded aspects of prevention to be part of their professional work, a source of job satisfaction and of value to the practice, its image and a marker of quality of care. Further studies are needed to clarify associations between dentists' perception of dental prevention and its practice.
A detailed analysis of the practice patterns of prevention-related care revealed that the percentages of time spent on preventive care, which differed between ‘more preventive’ and ‘less preventive’ dentists, were significantly different in practices that administered preventive care more than 20% of the time. Dentists in this study or their dental auxiliaries, provided oral hygiene instruction to 67% of their patients at some point in the patient's course of treatment and this percentage differed significantly as ‘more preventive’ and ‘less preventive’ dentists. The percentage of patients who received hygiene instruction was also associated with the administration of individualised caries prevention in the multiple regression analysis.
Our study clarified that a positive patient perception of preventive dentistry (as measured by the percentage of patients in the practice who are interested in caries prevention) and a higher percentage of patients in the practice who received hygiene instruction were associated with the use of individualised caries prevention to a higher percentage of patients. According to the results of the same questionnaire survey by the US DPBRN, dentists' individual characteristics, practice settings and dental procedures were associated with providing individualised caries prevention to a greater percentage of patients.9 Additionally, Brennan and Spencer30 noted that dentists' individual characteristics, practice settings and patient characteristics influenced the pattern of preventive care delivered. Our model also included dentists' individual characteristics, practice settings and dental procedures and the dentists' ratings of patients' preference for preventive care were related more strongly than those factors. In addition, a previous systematic review noted that potential barriers to the adherence to physicians' guidelines included dentists' and patients' preferences.31 ,32 As Cabana et al31 noted, potential barriers to the adherence to physicians' guidelines changed depending on the topic and it is possible that dentists' ratings of patient preference are strongly related to the practice of preventive dentistry.
However, our studies suggested that dentists' beliefs about the effectiveness of caries risk assessment were not related to their tendency to use individualised caries prevention. A possible reason for this is that the majority of participants (67%) agree that caries risk assessment is effective. This high percentage of agreement with the effectiveness of caries risk assessment is consistent with previous studies. According to the results of the same questionnaire by the US DPBRN, 77% of dentists answered that they agree with the effectiveness of caries risk assessment. Further studies are needed to clarify the relationship between the use of preventive dentistry and their beliefs about its effectiveness.
The main strength of this study was its relatively wide diversity of participants, with respondents from all seven regions of Japan. The age and gender distribution of this study sample was similar to the actual distribution of dentists in Japan (80% male, average age in the 40s),33 thereby enhancing the generalisability of the findings. However, the study results should be approached with caution. First, participants were not selected by random sampling, but rather by responding to the invitation to participate in the JDPBRN. Second, no objective standard for cut-off regarding an adequate prevalence of patients receiving individualised caries prevention has been established, although we used prior planned cut-offs with the mean from the previous US studies. Third, it is possible that the questionnaire's validity is influenced by the reimbursement/insurance system, which is quite different between the USA and Japan. Finally, given the cross-sectional nature of our study, causative relationships between factors and the provision of individualised caries prevention were difficult to assess.
We identified substantial variation in dentists' practice patterns regarding caries preventive dentistry in this study population. Individualised caries prevention was significantly related to provision of other preventive services and to the practice having a higher percentage of patients interested in prevention, but not to the dentist's belief about the effectiveness of caries risk assessment.
Contributors YY, NK, FS, YM, GHG and VVG contributed in arranging reagents/materials/analysis tools, conceived and designed the experiments and revised and reviewed the paper. NK, YM and FS performed the experiments. YY and NK analyzed the data and wrote the paper.
Funding Certain components of this work were supported by the National Institutes of Health grants U01-DE-16746, U01-DE-16747 and U19-DE-22516; a Grant-in-Aid for JSPS Fellows Grant number 23-10883 from the Japan Society for the Promotion of Science (JSPS), Japan.
Competing interests Two authors are dentists employed by a dental clinic (Dr Futoshi Sumida: Mikami Dental and Orthodontics Clinic and Dr Yuki Matsumoto: Matsumoto Dental Clinic).
Patient consent Obtained.
Ethics approval The Ethics Committee of Kyoto University Graduate School and Faculty of Medicine.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The translated version of these questionnaires is available at http://www.dentalpbrn.org/uploadeddocs/Study%201(Japanese%20Version.pdf). (Original English version: http://nationaldentalpbrn.org/pdf/Study%201%20questionnaire%20FINAL%20after%20pre-testing%20021306.pdf).