O riginal Paper Caries Research Caries Res 1996;30:29-33 Oral Hygiene as a Variable in Dental Caries Experience in 14-Year-Olds G. Rollet0 Public Dental Clinic, Lillehammer, Department of Orthodontics, Faculty o f Dentistry, University o f Oslo, Department o f Pedodontics and Caries Prophylaxis, Faculty of Dentistry, University o f Oslo, Norway FvflOQAfl ItO FlllOf ¡Hr U D U U I I U C L A JIU O C U K ey W o rd s A b stra c t Adolescence Caries experience Consumption of sweets Fluoride prophylaxis Oral hygiene The aim of the study was to examine the relationship between oral hygiene level and caries experience in 14-year-olds using fluoride dentifrices on a regular ba sis. Oral hygiene expressed as Gingival Bleeding Points (GBP) was recorded in 267 individuals in the county of Lillehammer in Norway. Total caries experience as DMFS and approximal carious lesions in the outer half o f the enamel (D ,), in the inner half of the enamel (D2), in dentin (D3), and fdled approximal surfaces were registered clinically and on standardized bite-wing radiographs. Using multiple regression analysis, oral hygiene level expressed as GB1 was the only factor that could account for variation in caries experience (DMFS). Any signif icant effect of consumption of sweets on caries experience could not be demon strated with the multivariate analysis. The average percentage of GBP (±SD) was 35.7± 10.0%. The individuals were divided into one group with good oral hygiene (GBP<35.7%) and one group with poor oral hygiene (GBP>35.7%). Signif icantly fewer carious lesions and fdled approximal surfaces were demonstrated in the group with good oral hygiene compared with the group with poor oral hygiene. About 16% of the study population used fluoride tablets or fluoride mouthrinses in addition to a fluoride toothpaste. Only in the good oral hygiene group, additional fluoride resulted in a lower caries experience compared with those using only a fluoride toothpaste. In the group with poor oral hygiene, addi tional fluoride did not result in lower caries experience. The study thus supported the view that during regular fluoride exposure oral hygiene level is an important variable to explain caries risk. It is well documented that, during the last few decades, not only the total caries prevalence has been reduced in the Nordic and in many European countries but there has also been a change in the distribution of caries in the dentition. Caries in the anterior teeth has almost disappeared and is increasingly becoming a pit and fissure phenomenon [Brunelle and Carlos, 1990; Kalsbeek and Verrips, 1990]. Caries KARGER E-Mail kargere« karger.ch Fax+41 61 306 12 34 © 1996 S. Karger AG. Basel 0008 6568/96/0301 0029$ 8.00/0 reduction can be explained nearly exclusively by a fluoride effect, and mainly by regular use of fluoride toothpastes [Glass, 1986; Jenkins, 1985; Rolla et al., 1991], Still some 10-15% of the schoolchildren show rather high caries activ ity, and 50-75% of orthodontic patients [Gorelick et ah, 1982; Banks and Richmond, 1994] develop enamel demi neralization on the labial surfaces during fixed appliance Bjorn Ogaard Department of Orthodontics Faculty o f Dentistry, University of Oslo PO Box 1109 Blindem N-0317 Oslo (Norway) Received: October 17.1994 Accepted after revision: May 15,1995 Downloaded by: Vanderbilt University Library 18.104.22.168 - 10/27/2017 7:08:53 PM BT 0galrTen‘ therapy. The caries picture is thus more complex today than it used to be in the past. Whereas the majority of studies concerning the relation ship between the level of oral hygiene and caries develop ment in the past showed no or little effect of oral hygiene, more recent studies show an increased caries rate in patients with insufficient oral hygiene [Bellini et al., 1981; StecksenBlicks and Gustafsson, 1986; Williams and Curzon, 1990; Bjertness, 1991], In a recent study, 0gaard et al. [1994a] showed that in 15-year-old Norwegians a clear relationship existed between good oral hygiene expressed as nonbleeding papillae, and low approximal caries development and pro gression. The reason for this change is uncertain and has at tracted little attention. It has been suggested that one reason could be that the final pi 1 in plaque in patients with poor oral hygiene could be so low that the enhancing effect on remincralization by fluoride was impaired [Rolla et al., 1991], The aim of the present study was to examine the relation ship between dental caries and oral hygiene in 14-year-olds using fluoride toothpastes regularly and additional fluoride prophylaxis in the form of tablets or mouthrinses. Consumption o f Sweets The individuals were interviewed about the consumption of sweets. Based on this information three groups were established: (1) individuals consuming sweets daily (n = 71); (2) individuals consum ing sweets 3-4 days per week (n = 157). and (3) individuals consuming sweets once a week (n = 13). Caries Experience The sample was also split into two groups according to low or high caries experience. The demarcation point was set at DMFS = 6, which was the average DMFS of the study population. The DMFS scores were given from both clinical and radiographical evaluations. The group with low caries experience (D M FSS6) comprised 164 individ uals, and the group with high caries experience (D M FS>6) com prised 103 individuals. Statistical A na lysis Differences between the mean values o f D|, D ., D, and FSA o f the two groups were evaluated using t tests. Differences between high and low caries level in individuals with good or poor oral hygiene were estimated by yy statistics. A one-way analysis o f variance was used to compare caries experience (DMFS) of the individuals according to consumption of sweets. A multiple regression analysis was used to study the influence of all the independent variables (GBI%, consump tion of sweets and use o f addition fluoride supplements) on the de pendent variable DMFS. All the data were processed using the Mini tab Data Analysis Software (Minitab Inc, 3081 Hnterprisc Drive, State College. Pa., USA). The level of significance was set at 5%. M a te ria ls and M e th o d s Gingival /Heeding Index Gingival Bleeding Index (GBI) by Ainamo and Bay  was used as a measure for the patients’ hygiene. A blunt pocket probe was used for gentle probing of the orifice o f the gingival crevice. The pres sure used was about 20 g. If bleeding occurred within about 10 s after testing, a positive finding was recorded. The number o f gingival bleed ing points (GBP) was recorded from the buccal, mesial and lingual surfaces o f the teeth (84 sites). The number of positive findings was then expressed as a percentage o f the maximum number o f sites. Approximal Caries Data Approximal caries data were recorded from standardized bite-wing radiographs. Caries in the anterior teeth was recorded from clinical ex amination and on radiographs in addition if necessary. There were only a few children in this age group with caries in their anterior teeth. The following registrations were performed on premolars and mo lars: D| = approximal lesions in the outer half of the enamel; D: = ap proximal lesions in the inner half of the enamel; D s = approximal le sions in dentin and FSA = filled approximal lesions. The sum of ca rious approximal surfaces (D|+D-.+D 5) was calculated. 30 Caries Res 1996:30:29- 33 R e su lts The average number of GBP calculated in percent for the whole group was 35.7± 10.0. The group was divided into two subgroups: group 1 with good oral hygiene (GBP<35.7%) and group 2 with poor oral hygiene (GBP>35.7%). There were 146 children in group I and 121 children in group 2. In group 1 the mean number of GBP was 28.6±5.5%, and in group 2 it was 44.3±7.0%. The mean numbers of carious approximal surfaces at the age o f 14 years are shown in table 1. Group I had significant ly fewer approximal lesions and fillings than group 2 with many GBP. Table 2 shows caries experience in the individuals con suming sweets daily, 3-4 days per week or only once per week. The individuals consuming sweets daily had signif icantly higher caries experience than those few consuming sweets only once per week (p = 0.03, one-way analysis of variance). There was no significant difference in caries ex perience between those who consumed sweets daily or 3 4 days per week. Table 3 shows the result of the multiple re gression analysis. Oral hygiene status as BGI% was the only factor that could account for variation in caries incidence (DMFS). Mathicscn/Dgaard/Rol la Downloaded by: Vanderbilt University Library 22.214.171.124 - 10/27/2017 7:08:53 PM This study was carried out at the Public Dental Service Center in the town o f Lillehammer in the eastern part o f Norway. All 14-yearolds (n = 267) from the Dental Clinic in Lillehammer were examined at their yearly dental checkups from April to June 1993. These children came from the town o f Lillehammer and the surrounding areas (22,000 inhabitants), and all of them claimed to use fluoride toothpaste regu larly. About 16% o f the children used fluoride tablets or fluoride mouthrinses in addition to fluoride toothpaste. The clinical and radiographical examinations were carried out by the same dentist (A.T.M.). Group Mean GBP, % n D, D, d3 D,+ D,+ D., FSA 1 2 a 28.6±5.4 44.3±7.0 0.0000 146 121 1,4± 1.8 2.3+2.3 0.008 0.7±1.4 1.511.9 0.0003 0.210.8 0.711.3 0.0003 2.212.9 4.514.3 0.210.6 1.412.4 0.0000 0.0000 ’ Level of significance obtained from t tests between the groups. Table 2. Caries experience (DMFS) in 14-year-olds according to frequency o f consumption o f sweets Frequency of consumption n DMFS mean 1 SD Daily 3-4 times per week Once per week 71 157 13 8.717.0 6.216.6 5.716.8a a Statistically significantly different from daily consumers (one-way analysis o f variance). The x 2 test showed that only in case of good oral hygiene supplements to fluoride toothpaste resulted in lower caries experience (x2 = 8.69, p = 0.01). When oral hygiene was poor, fluoride supplements apparently had no additional ef fect (x2 = 0.384, p<0.1). D is c u s s io n Caries has been markedly reduced among children in Lillehammer in the last 30 years. From 1559 to 1984, Birkeland and Brageline  found a decrease in MFS from 34.1 to 7.5 (78%). In the present study the mean number of DMFS, excluding D| lesions, was 4.7, indicating a further decrease in caries prevalence in the area. A continual de crease in caries prevalence among Norwegian children has recently been reported by Haugejorden . Flowever, a high prevalence of initial enamel lesions which are general ly not fdled was found in the present study. About 39% of all the individuals had no initial lesions in the outer half of the enamel (Di = 0) on approximal surfaces of molars and pre molars. This is comparable to a study from another district in the same county, where only 34% o f 388 15-year-olds had no initial lesions in the outer half of the enamel (D| = 0) on approximal surfaces of molars and premolars (0gaard and Oral Hygiene, Fluoride Exposure and Caries Experience Table 3. Results o f multiple regression analysis with categories of variables: oral hygiene status as GBI, consumption o f sweets and use o f fluoride supplements (fluorice mouthrinses or fluoride tablets) as independent variables and DMFS as dependent variable GBI, % Sweets F-supplements Constant R-square 30.6% Coefficient SD t ratio P 0.34 0.31 1.89 -4.45 0.04 0.19 1.04 2.01 9.35 1.61 -1.81 -2.14 0.000 0.108 0.072 0.033 Rosier, 1991], By taking the oral hygiene level into consid eration, almost 70% o f the children with poor oral hygiene and 54% of children with good oral hygiene had one or more lesions in the outer half of the enamel (D, > 0 ) on ap proximal surfaces of molars and premolars (fig. 1). Only 20% of the children with poor oral hygiene and 39% of the children with good oral hygiene had no approximal lesions at all (D|+D2+D3 = 0). The high prevalence of initial lesions at the age of 14 shows that caries is a potential problem even at an early age, and especially with poor oral hygiene. The rationale for evaluating oral hygiene by registration of bleeding points is that the gingival condition is thought to be a better indicator of the oral hygiene level than the amount of plaque at a certain day. A patient who brushes his or her teeth before an appointment with the dentist may be judged to have a good oral hygiene by a plaque index, whereas the GBP index will give a more valid picture of the current oral hygiene status of the patient. A univariate analysis of the data shows a statistically sig nificant relationship between consumption of sweets and caries experience (table 2). However, in a multivariate anal ysis of the data, taking oral hygiene level into account, no relationship between consumption of sweets and caries could be demonstrated. Thus, the statistical relationship found after applying univariate analysis was probably the Caries Res 1996;30:29-33 3( Downloaded by: Vanderbilt University Library 126.96.36.199 - 10/27/2017 7:08:53 PM Table 1. PercentageofG BP(±SD )and mean (±SD ) D,, D;. D5, sum o f D |+D 2+D 3 and PSA in group I with good oral hygiene (few GBP) and in group 2 with poor oral hy giene (many GBP) result o f confounding. Sundin et al.  have reported that in a population exposed regularly to fluoride no strong relationship exists between caries and consumption of sweets. Using multiple regression analysis, oral hygiene level was the only factor that could account for variation in caries experience. This supports the findings by 0gaard et al. [1994b] from another county in Norway that during regular use of fluoride toothpaste oral hygiene is a good indicator for evaluating caries risk. The fluoride factor is most likely so strong that it can resist quite high exposure to sugar as long as the oral hygiene level is reasonably good. Interest ingly, even during the pre fluoride era of the 1960s, the com bination of plaque removal and fluoride was more effective than fluoride alone [Koch and Lindhe, 1970]. A relationship between social class and caries incidence has been demonstrated [Hausen et al„ 1981]. No informa tion about social classes was available in the present study as such information is getting increasingly more sensitive for research purposes. However, the population in Lillehammer is fairly homogenous without any large differences in socioeconomic factors. Furthermore, social class most likely influences oral hygiene habits and is thus indirectly accounted for in the present investigation. Although all the children in this study claimed to use a fluoride toothpaste regularly, the amount of fluoride that each child obtained every day varied according to how often teeth were brushed in a day. However, none o f these children showed as much caries as the children did before fluoride toothpaste came into general use in 1971. Very few tooth pastes without fluoride are sold in Norway. About 16% of the children used fluor tablets or fluoride mouthrinses in addition to fluoride toothpaste. In the group with good oral hygiene, this resulted in less caries among the children who used some fluoride in addition to fluoride toothpaste. In the group with poor oral hygiene, no differ ence was found among those with fluoride in addition to fluoride toothpaste and the others. Also Seppii and Tolonen  showed that simply increasing the number of fluo ride varnish applications in high-risk individuals did not re sult in greater caries reduction. It may be speculated that the reduced clinical effect of fluoride in the presence of poor oral hygiene is related to the saturation level with respect to fluorapatite in the plaque fluid. In the prefluoridc era even small amounts of plaque were able to cause demineralization and caries develop ment. Only a perfect oral hygiene was able to inhibit caries during this period, and the number of such patients was so low that this effect did not appear in epidemiological statis tics. At present, when fluoride is used regularly, mostly as fluoride-containing toothpaste, fluoride inhibits demineral ization and enhances remineralization during moderate challenges. A certain amount of plaque is probably accept able under these conditions without caries occurring. The reason for the difference in significance of oral hygiene in relation to dental caries before and after the fluoride era is then conceivably that small to moderate amounts of plaque which gave caries in the prefluoride era do not produce car ies at present. The problem occurs when pH drops so low that saliva is undersaturated also with respect to fluorapatite [Larsen, 1990], This can be the situation during poor oral hygiene and may explain why additional fluoride supple mentation does not give enhanced clinical effect [Ogaard et al„ 1994b). Based on the findings from the present study it is con cluded that oral hygiene is an important factor in the preven tion of caries in a population which is exposed to fluoride. Good oral hygiene and fluoride use then appear to have syn ergistic effects. R efe rences 32 Caries Res 1996:30:29 33 Bjertness E: The importance o f oral hygiene on var iation in dental caries in adults. Acta Odontol Scand 1991;49:97-102. 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