Study group
A sample of 1000 individuals, 20–89 years old registered as living in the county of Skåne, Sweden, was randomly selected for a larger cross sectional study of oral health [18]. From the original sample, a total of 451 individuals (47 %), 232 women (51 %) and 219 men (49 %) agreed to participate and were examined clinically. Data from 446–450 subjects could be analysed for different purposes as full data from the questionnaire, the history and the clinical examination were missing for one to five individuals. The study design was approved by the Ethical Board at the University of Lund, Sweden (Dnr. 513/2006). Patients were informed about the survey and signed a written consent.
Information from the questionnaire, history, radiological and clinical findings [18] relevant to this study, relating to caries and patients self-assessment of future oral treatment need were extracted for further analyses. Variables evaluated by clinical examiners in this study were: past and new caries experience (DMFT, DS, incipient lesions), general diseases or conditions and medication associated with dental caries, plaque amount, oral dryness, intake frequency of soft drinks and dental erosions.
Questionnaire
Before the clinical examinations the participants answered a questionnaire containing questions concerning oral health and oral health related factors [19]. The non-response analysis has been described earlier [18]. Individuals in the age group 80–89 were less likely to participate (OR = 2.82). Patients scored their own future treatment need in five grades from ‘very low’ to ‘very high’ as well as ‘don’t know’ by answering the question: How do you judge your future oral treatment need? Due to few individuals (n = 19) in the ‘very high risk’ group, they were included in the ‘high risk’ group.
History
General diseases, conditions and medication associated with dental caries was recorded and entered into the Cariogram according to the manual. Estimations of intake frequency of soft drinks, citrus fruits and apples were recorded in the history, and graded; ‘less than once a week, once a week, daily and several times a day’.
Clinical examination
The clinical examinations were performed during 2007–2008 and took place at the Faculty of Odontology at Malmö University, Sweden, and at three clinics at the PDS in the county of Skåne. The examinations were performed by eight dentists all employed at the Department of Oral Diagnostics, Faculty of Odontology, Malmö University and 90.5 % were performed by four of them. The examiners were coordinated regarding the diagnostic criteria through comprehensive written instructions, practice and through discussing clinical cases before the clinical examinations. All patients were examined using a standard examination procedure in standard surgeries [18].
Decayed, missing and filled teeth and surfaces (DMFT and DS including incipient lesions) were recorded. Caries lesions were determined using standard clinical criteria aided by mirror, probe (Hu-Friedy EXD57) and digital bite-wing radiographs. On radiographs, lesions that only included the enamel were recorded as incipient lesions, and lesions that extended into the dentine were recorded as manifest caries. Clinically, incipient lesion criterion was opacity with or without roughness. Activity was determined by appearance of lesions and active dentine caries was determined if the surface was soft by the probe [18].
Dental erosions were assessed on buccal and lingual surfaces of upper incisors and canines using a scoring system (grade 0–4) where the severity of the erosion was graded according to Johansson and co-workers [20]. Dental erosion was included in the study as some risk factors overlap with those for caries and presence of erosions might influence self-assessment of oral health. Plaque was recorded as present or not on four surfaces on each tooth. The total percentage of plaque covered surfaces was calculated for each patient.
Oral dryness was determined by the examiner by the use of a mouth mirror at the clinical examination. The score ‘Severe’ was recorded if the mouth mirror adhered to the buccal mucosa. ‘Some dryness’ was scored if there was a friction between the mouth mirror and the buccal mucosa.
Paraffin-stimulated whole saliva was collected for 5 min for estimation of secretion rate and expressed as ml/min. Salivary mutans streptococci, lactobacilli and saliva buffering capacity were determined with Dentocult® SM - Strip mutans, Dentocult® LB and Dentobuff® Strip, respectively. Test kits were obtained from Orion Diagnostica, Espoo, Finland and handled according to the instructions of the manufacturer.
CRA based on clinical judgement
The clinical guidelines for risk assessment were based on patient’s history, past and present disease, general and technical conditions. The caries risk assessment was based on past and present caries, clinical activity of lesions, and evaluation of risk factors (dietary content and intake frequency of carbohydrates, fluoride exposition and plaque amount, general health, medication, social situation and expected cooperation). The periodontal risk assessment was based on presence of gingivitis, marginal bone loss, plaque situation, general health, medication, social situation and expected cooperation. The general risk assessment was based on presence of general diseases, medication, dental anxiety and communication ability. The technical conditions were based on the extent of restorations and prosthetic reconstructions incorporating general health, medication, social situation and expected cooperation. The clinical guidelines for risk assessment were modified after the Public Dental Service guidelines for risk assessment in adults in Skåne region as described in Hänsel Petersson et al. 2013 [21]. The examiners had thus a reasonably good overview of the patient’s oral situation. The risk assessment was performed directly after the clinical examination and patients were scored from low to very high risk based on the protocol paired with their own clinical judgement. Caries, periodontal, technical and general risk was scored ‘low risk’ as 1 point, ‘moderate risk’ as 2, ‘high risk’ as 3 and ‘very high risk’ as 4 points in each group. To be considered as “moderate risk” indicates that the patient was categorized in between low or high risk group. Patients who are at “moderate risk” for dental caries have an uncertain probability to develop new caries lesions unlike a patient being classified to ”high risk” or “low risk”. The patients often have a combination of different underlying risk factors. The sum of examiners risk score was defined as: ‘low risk’ 4 points, ‘moderate risk’ 5–8 points and ‘high/very high risk’ 9–16 points. At this time, the dentists were not aware of the data from the questionnaire, the results of the salivary tests or the Cariogram score.
CRA based on the Cariogram
In this study, data from the questionnaire, history, laboratory and caries data were evaluated and entered into the Cariogram model, except for dietary content where only the lactobacillus score were used [8]. The Cariogram was used in standard setting without altering the “clinical judgement”. Information included scoring of caries experience, DMFT, DS and combining DS and incipient lesions; general disease, conditions and medications associated with dental caries; dietary content based on lactobacillus test count; dietary intake frequency based on estimation of number of meals and snacks per day; plaque amount; mutans streptococci colonization using the Strip mutans test; fluoride programme based on fluoride exposure; saliva secretion using paraffin-stimulated secretion rate; saliva buffering capacity using the Dentobuff test. The intake frequency of diet, soft drinks and fruits was compiled from self-reports.
Statistical methods
Eleven variables from the questionnaire and history, related to caries and patients self-assessment of future treatment need were extracted for further analyses.
The Pearson Chi-2 test was used to test the relation between risk assessment based on clinical judgement and CRA using the Cariogram. The same test was used to test the relation between patient’s own perceptions of future oral treatment need with the sum of examiners risk score based on clinical judgement.
The relation between CRA (scored as 0 = low-moderate and 1 = high) and clinical variables were analysed using a logistic regression. A significance level of 5 % was used in all tests. Statistical calculations were performed in the Statistical Package for the Social Science (SPSS for Windows, version 21, Chicago Ill., USA).