Oral hygiene frequency and presence of visible biofilm in the primary dentition

The purpose of this study was to associate oral hygiene frequency and presence of visible biofilm in the primary dentition. The sample consisted of 90 children, aged up to 4 years old, outpatients of the University Hospital of the Rio de Janeiro State University. The examinations were carried out in a dental office by a single trained examiner who was aided by an assistant. The parents answered a structured questionnaire about oral hygiene methods and frequency. Two biofilm indices, one simplified (BF1) and the other conventional (BF2), were used. BF1 classifies biofilm as absent, thin or thick, in anterior and/or posterior teeth, and provides a score for the patient, whereas BF2 classifies biofilm as absent or present, provides scores for three surfaces of each tooth and the final score is the percentage of tooth surfaces with biofilm. More than half of the parents (51 56.7%) reported they cleaned their child’s teeth at least twice a day, while 7 (7.8%) had never cleaned their child’s teeth. BF1 revealed that 12.2% (11) of the children had no visible biofilm, 37.8% (34) had thin biofilm in anterior and/or posterior teeth, 27.8% (25) had thick biofilm in anterior or posterior teeth and 22.2% (20) had thick biofilm in both anterior and posterior teeth. BF2 revealed a mean value of 21.8% (s.d. 16.5). No statistically significant correlations were found between oral hygiene frequency and the two biofilm indices (p > 0.05), indicating that oral hygiene frequency was not associated to oral hygiene quality in the evaluated sample. Descriptors: Oral hygiene; Dental plaque index; Dentition, primary. Resumo: O objetivo deste estudo foi associar freqüência de higiene bucal e presença de biofilme visível na dentição decídua. A amostra constou de 90 crianças com idade até 4 anos, cadastradas no Hospital Universitário da Universidade do Estado do Rio de Janeiro. Os exames foram realizados em consultório odontológico por um único examinador treinado, auxiliado por um anotador. Os pais responderam a um questionário estruturado sobre métodos e freqüência de higiene bucal. Foram utilizados dois índices de biofilme: um simplificado (BF1) e um convencional (BF2). O BF1 classifica o biofilme como ausente, fino ou espesso, em dentes anteriores e/ou posteriores, gerando um escore para o paciente, enquanto o BF2 classifica o biofilme como ausente ou presente, fornece escores a três superfícies de cada dente e o escore final corresponde ao percentual de superfícies com biofilme. Mais da metade dos pais (51 56,7%) relataram limpar os dentes dos filhos pelo menos duas vezes ao dia ao passo que 7 (7,8%) nunca tinham limpado os dentes dos filhos. O BF1 demonstrou que 12,2% (11) das crianças não apresentavam biofilme visível, 37,8% (34) apresentavam biofilme fino em dentes anteriores e/ou posteriores, 27,8% (25), biofilme espesso em dentes anteriores ou posteriores, e 22,2% (20), biofilme espesso em dentes anteriores e posteriores. O BF2 revelou uma média de 21,8% (d.p. 16,5). Não foram encontradas correlações estatisticamente significativas entre a freqüência de higiene bucal e os índices de biofilme (p > 0,05), demonstrando que a freqüência de higiene bucal não esteve associada à qualidade da mesma na amostra estudada. Descritores: Higiene bucal; Índice de placa dentária; Dentição decídua. Ana Paula Pires dos Santos(a) Mariana Canano Séllos(b) Maria Eliza Barbosa Ramos(c) Vera Mendes Soviero(d) (a) Master’s degree in Pediatric Dentistry; (b)DDS; (c)Professor, Department of Diagnosis and Surgery; (d)Professor, Department of Community and Preventive Dentistry – School of Dentistry, Rio de Janeiro State University. Pediatric Dentistry Corresponding author: Ana Paula Pires dos Santos Av. Roberto Silveira, 187/201 Centro Petrópolis RJ Brazil CEP: 25685-040 E-mail: paulapires@globo.com Received for publication on Mar 16, 2006 Sent for alterations on Jun 13, 2006 Accepted for publication on Aug 28, 2006 Santos APP, Séllos MC, Ramos MEB, Soviero VM Braz Oral Res 2007;21(1):64-9 65 Introduction Several studies have assessed the prevalence of early childhood caries (ECC) throughout the world. Milnes13 (1996), in a comprehensive review, observed a prevalence rate from 1 to 12% in developed countries and prevalence as high as 70% in developing countries or within disadvantaged populations. In Brazil, a national survey with 12,117 children aged 18-36 months old demonstrated that 26.9% of them had at least one cavitated caries lesion.4 Brazilian studies that have also registered noncavitated lesions showed prevalence between 35.9 and 55.3%.3,11,20 Surveys including AfroAmerican and Hispanic immigrants in the USA also considering noncavitated lesions have found a prevalence of ECC of 20% and 59%, respectively.15,16 ECC should be considered a multifactorial disease whose etiology involves biological,22 psychosocial and behavioral factors.17 Individuals from lower socioeconomic strata find it hard to obtain professional health care and to live in a healthy environment, resulting in the development of negative behaviors towards their oral health.17 Thus, social class can be regarded as a controversial factor in the analysis of oral hygiene habits, such as toothbrushing.21 Studies that evaluated oral health behaviors in infants and preschool children have found that 36 to 92% of them had their teeth cleaned at least once a day.6,9,12,19,20,25 Provided cleaning is sufficiently thorough and performed daily, toothbrushing is considered to be the most reliable means of controlling biofilm.10 Clinical trials have already demonstrated that biofilm accumulation without mechanical disturbance leads to the development of white spot lesions.24 Daily toothbrushing associated to fluoride dentifrice has been considered the main reason for the decrease of caries prevalence since the 70’s. In spite of that, the studies fail to show, at the population level, a clear association between oral hygiene and caries, probably due to the poor quality of biofilm removal performed by the patients.14 The association between oral hygiene habits and ECC is also controversial as some studies have found association between these variables,7,19,23 while others have not.6,12,25 However, when there is a high quality of biofilm removal, toothbrushing can be considered efficient to control caries.14 Concerning the quality of oral hygiene in children with primary dentition, it has already been evaluated by means of different biofilm indices.2,3,9,11,20 On the other hand, the association between frequency and quality of oral hygiene in young children has not been highlighted in the literature. The aim of this study was to associate oral hygiene frequency with the presence of visible biofilm in infants and preschool children using a simplified visible biofilm index as well as a conventional one. Material and Methods Subjects and study design The sample of this cross-sectional study consisted of 90 selected healthy patients, of both sexes, aged up to 4 years old and outpatients of the Pediatric Ambulatory of the University Hospital, Rio de Janeiro State University. It was a convenience sample and, to be included in the study, children should present, at least, the eight primary incisors erupted. The examinations were not previously scheduled. Parents were invited to participate while they were waiting for an ordinary appointment with the pediatrician. Ethical aspects Participation in the study was voluntary and written consent forms were obtained from parents. The study was approved by the Ethical Committee of the Biomedical Center, Rio de Janeiro State University (967-CEP/HUPE). Parental interview Parents were questioned about oral hygiene practices including: 1) how often did they clean their child’s teeth; 2) which product was used to clean their child’s teeth, meaning that they should point out if they used toothbrush with or without fluoride dentifrice, gauze, cotton or other. Parents were not asked about any specific technique or method of toothbrushing. All of them received information on caries prevention. Biofilm evaluation All clinical assessments were carried out in a dental office by a single trained examiner who was aided by an assistant. The children sat either in the dental Oral hygiene frequency and presence of visible biofilm in the primary dentition Braz Oral Res 2007;21(1):64-9 66 chair or in the parent’s lap. Mouth mirrors, exploratory probes and gauze were used. A simplified and a conventional biofilm index, both already employed in previous studies, were used. The presence of biofilm was evaluated without a disclosing solution. The simplified index,18 called in this study BF1, gives a score to the patient according to the amount of visible biofilm accumulated (absent, thin or thick) in anterior and/or posterior teeth, whereas the conventional index,1 called in this study BF2, evaluates the presence of visible biofilm in the mesial, buccal and lingual surfaces of all teeth. The BF118 was chosen to be used in this study because it is simple and easy to apply, which is an advantage when dealing with young children. However, as it was not used in such young children before, it was decided that a conventional index be used as well. The index proposed by Ainamo, Bay1 (1975) (BF2) was selected as previous studies in the primary dentition have already assessed biofilm based on its criteria.2,26 The index proposed by Ribeiro et al.18 (2002) (BF1) was modified by uniting some scores. Originally, the patient could be assigned a score ranging from 0 to 5. In the modified index, the scale ranges from 0 to 3, according to Chart 1. Patients were assigned score 0 when no visible biofilm was present, even after the teeth were dried with gauze. Score 1 was given when there was thin biofilm in anterior and/or posterior teeth (visible biofilm that could be seen only after careful drying with gauze). When only one region, anterior or posterior, presented thick biofilm, the patient was assigne


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Oral hygiene frequency and presence of visible biofilm in the primary dentition Freqüência de higiene bucal e presença de biofilme visível na dentição decídua Abstract: The purpose of this study was to associate oral hygiene frequency and presence of visible biofilm in the primary dentition.The sample consisted of 90 children, aged up to 4 years old, outpatients of the University Hospital of the Rio de Janeiro State University.The examinations were carried out in a dental office by a single trained examiner who was aided by an assistant.The parents answered a structured questionnaire about oral hygiene methods and frequency.Two biofilm indices, one simplified (BF1) and the other conventional (BF2), were used.BF1 classifies biofilm as absent, thin or thick, in anterior and/or posterior teeth, and provides a score for the patient, whereas BF2 classifies biofilm as absent or present, provides scores for three surfaces of each tooth and the final score is the percentage of tooth surfaces with biofilm.More than half of the parents (51 -56.7%) reported they cleaned their child's teeth at least twice a day, while 7 (7.8%) had never cleaned their child's teeth.BF1 revealed that 12.2% (11) of the children had no visible biofilm, 37.8% (34) had thin biofilm in anterior and/or posterior teeth, 27.8% (25) had thick biofilm in anterior or posterior teeth and 22.2% (20) had thick biofilm in both anterior and posterior teeth.BF2 revealed a mean value of 21.8% (s.d.16.5).No statistically significant correlations were found between oral hygiene frequency and the two biofilm indices (p > 0.05), indicating that oral hygiene frequency was not associated to oral hygiene quality in the evaluated sample.Descriptors: Oral hygiene; Dental plaque index; Dentition, primary.

Introduction
Several studies have assessed the prevalence of early childhood caries (ECC) throughout the world.Milnes 13 (1996), in a comprehensive review, observed a prevalence rate from 1 to 12% in developed countries and prevalence as high as 70% in developing countries or within disadvantaged populations.In Brazil, a national survey with 12,117 children aged 18-36 months old demonstrated that 26.9% of them had at least one cavitated caries lesion. 4Brazilian studies that have also registered noncavitated lesions showed prevalence between 35.9 and 55.3%. 3,11,20Surveys including Afro-American and Hispanic immigrants in the USA also considering noncavitated lesions have found a prevalence of ECC of 20% and 59%, respectively. 15,16CC should be considered a multifactorial disease whose etiology involves biological, 22 psychosocial and behavioral factors. 17Individuals from lower socioeconomic strata find it hard to obtain professional health care and to live in a healthy environment, resulting in the development of negative behaviors towards their oral health. 17Thus, social class can be regarded as a controversial factor in the analysis of oral hygiene habits, such as toothbrushing. 21Studies that evaluated oral health behaviors in infants and preschool children have found that 36 to 92% of them had their teeth cleaned at least once a day. 6,9,12,19,20,25rovided cleaning is sufficiently thorough and performed daily, toothbrushing is considered to be the most reliable means of controlling biofilm. 10linical trials have already demonstrated that biofilm accumulation without mechanical disturbance leads to the development of white spot lesions. 24Daily toothbrushing associated to fluoride dentifrice has been considered the main reason for the decrease of caries prevalence since the 70's.In spite of that, the studies fail to show, at the population level, a clear association between oral hygiene and caries, probably due to the poor quality of biofilm removal performed by the patients. 14The association between oral hygiene habits and ECC is also controversial as some studies have found association between these variables, 7,19,23 while others have not. 6,12,25However, when there is a high quality of biofilm removal, toothbrushing can be considered efficient to control caries. 14ncerning the quality of oral hygiene in children with primary dentition, it has already been evaluated by means of different biofilm indices. 2,3,9,11,20On the other hand, the association between frequency and quality of oral hygiene in young children has not been highlighted in the literature.
The aim of this study was to associate oral hygiene frequency with the presence of visible biofilm in infants and preschool children using a simplified visible biofilm index as well as a conventional one.

Subjects and study design
The sample of this cross-sectional study consisted of 90 selected healthy patients, of both sexes, aged up to 4 years old and outpatients of the Pediatric Ambulatory of the University Hospital, Rio de Janeiro State University.It was a convenience sample and, to be included in the study, children should present, at least, the eight primary incisors erupted.The examinations were not previously scheduled.Parents were invited to participate while they were waiting for an ordinary appointment with the pediatrician.

Ethical aspects
Participation in the study was voluntary and written consent forms were obtained from parents.The study was approved by the Ethical Committee of the Biomedical Center, Rio de Janeiro State University (967-CEP/HUPE).

Parental interview
Parents were questioned about oral hygiene practices including: 1) how often did they clean their child's teeth; 2) which product was used to clean their child's teeth, meaning that they should point out if they used toothbrush with or without fluoride dentifrice, gauze, cotton or other.Parents were not asked about any specific technique or method of toothbrushing.All of them received information on caries prevention.

Biofilm evaluation
All clinical assessments were carried out in a dental office by a single trained examiner who was aided by an assistant.The children sat either in the dental chair or in the parent's lap.Mouth mirrors, exploratory probes and gauze were used.A simplified and a conventional biofilm index, both already employed in previous studies, were used.The presence of biofilm was evaluated without a disclosing solution.The simplified index, 18 called in this study BF1, gives a score to the patient according to the amount of visible biofilm accumulated (absent, thin or thick) in anterior and/or posterior teeth, whereas the conventional index, 1 called in this study BF2, evaluates the presence of visible biofilm in the mesial, buccal and lingual surfaces of all teeth.The BF1 18 was chosen to be used in this study because it is simple and easy to apply, which is an advantage when dealing with young children.However, as it was not used in such young children before, it was decided that a conventional index be used as well.The index proposed by Ainamo, Bay 1 (1975) (BF2) was selected as previous studies in the primary dentition have already assessed biofilm based on its criteria. 2,26he index proposed by Ribeiro et al. 18 (2002) (BF1) was modified by uniting some scores.Originally, the patient could be assigned a score ranging from 0 to 5. In the modified index, the scale ranges from 0 to 3, according to Chart 1.
Patients were assigned score 0 when no visible biofilm was present, even after the teeth were dried with gauze.Score 1 was given when there was thin biofilm in anterior and/or posterior teeth (visible biofilm that could be seen only after careful drying with gauze).When only one region, anterior or posterior, presented thick biofilm, the patient was assigned score 2. Finally, when there was thick biofilm in both anterior and posterior teeth (visible biofilm that could be seen without drying), the patient was assigned score 3.
Concerning the index proposed by Ainamo, Bay 1 (1975) (BF2), the scores 0, for absent biofilm, and 1, for present biofilm, were recorded for mesial, buccal and lingual surfaces of each tooth in a specific form.The percentage of tooth surfaces with visible biofilm was calculated.

Statistical analysis
The data were processed by means of the SPSS software, release 8.0 for Windows (SPSS Inc., Chicago, IL, USA) for descriptive analyses of oral hygiene frequency, oral hygiene method and biofilm indices.Spearman's correlation test was used to determine the association between oral hygiene frequency and the biofilm indices.The level of statistical significance was set at 5%.

Results
More than half of the parents (51 -56.7%) reported they cleaned their child's teeth at least twice a day.Twenty-one (23.3%) used to clean their child's teeth once a day, 11 (12.2%),occasionally, and 7 (7.8%) reported that their child's teeth had never been cleaned (Table 1).
The use of toothbrush associated to fluoride dentifrice was the most common way of cleaning the child's teeth, which was reported by 70% (63) of the parents (Table 2).
Table 4 shows that the percentage of BF2 ranged from 0 to 83.3%, with a mean of 21.8% (s.d.16.5).
No significant correlations (p > 0.05) could be found between oral hygiene frequency and presence of visible biofilm expressed by both indices (Table 5).
Among the 51 (56.7%) children who had their teeth cleaned at least twice a day, 27 (52.9%)had scores 0 or 1, and 24 (47.1%) had scores 2 or 3 for BF1.Regarding BF2, despite the decrease from 30.9% among those whose teeth were never cleaned to 19.8% among those whose teeth were cleaned twice a day or more, this difference was not statistically significant.

Discussion
The presence of caries in infants and preschool children has been carefully studied and several risk factors have already been evaluated in order to determine their association with caries occurrence.,25 Some of these studies concluded that there was either no association or a weak association between oral hygiene and caries. 5,6,12,25However, Wendt et al. 26 (1994) observed that if the habit of daily toothbrushing is adopted at as early as one year old, it is more likely that children will be caries free by the age of three.
The role of dental biofilm accumulation in caries initiation, progression and control is well established, 24 which demonstrates that the sole evaluation of oral hygiene habits may be of limited value.Moreover, the report of toothbrushing habits is subject to response bias 17 and gives no indication of the effectiveness of biofilm removal. 21n the present study, 11 (12.2%)parents reported    1).This frequency is in accordance with that found by Dini et al. 6 (2000), who observed that 85.3% of the 245 Brazilian children aged 3 to 4 years old had their teeth brushed at least once a day.The frequency of oral hygiene in the present study can be considered high when compared to that of another Brazilian study, which found that just 36% of the sample aged 12 to 36 months had their teeth cleaned. 19The percentage of oral hygiene frequency tends to be lower when children younger than 12 months old are included in the samples.In Saipan (USA), among 3,750 children aged 6 to 36 months, 54% used to have their teeth cleaned once or twice a day. 12In another Brazilian study, daily oral cleaning was observed in 76.3% of 80 children under 36 months old. 20In Thailand, in a group of 387 dentate children aged 6 to 19 months, 64.8% of the parents reported to have the habit of cleaning their child's teeth. 25ctually, more attention should be directed at assessing not only the oral hygiene habits and frequency of toothbrushing but also the quality of oral hygiene.Few studies comprising young children have assessed oral hygiene quality, 2,3,9,11,20 though many biofilm and gingival indices have already been devised as appropriate methods to evaluate oral hygiene quality.
The simplified visible biofilm index (BF1) used in the present study has been employed in its original version in a sample of children with primary and mixed dentition. 18In the present study, however, the index was modified to reduce the number of scores and facilitate its application in very young children.The other index, the visible plaque index, 1 cited in this study as BF2, was used as it has been employed in a large number of studies since its first description.
The sole evaluation of biofilm may not be enough as patients tend to improve dental cleanliness when they know they will be examined by a dentist.Therefore, gingival assessment is recommended. 8n this study, however, the parents were not aware that their child would be seen by a dentist.Children were scheduled for a medical appointment and, once in the waiting room, were invited to undergo a dental examination.Although the association between biofilm and gingival indices has not been evaluated in this study, it would be interesting to combine biofilm and gingival assessment in a further research involving this age group.
The results of this study showed that the children who had their teeth cleaned twice or more times a day were not necessarily the same that had thin biofilm or no visible biofilm (Table 5).According to BF1, about half of the children who had their teeth cleaned at least twice a day presented thick biofilm.Regarding BF2, despite the decrease in the percentage of dental surfaces with biofilm among those whose teeth were cleaned twice a day or more, this difference was not statistically significant.The lack of association between the reported toothbrushing frequency and the presence of visible biofilm is in agreement with Habibian et al. 9 (2001), whose results also failed to show this association in infants, indicating that a more frequent habit of toothbrushing may not reflect better oral hygiene quality.This fact places emphasis on the need for more specific guidance regarding dental cleaning.Although parents brushed their child's teeth, they did not manage to disturb biofilm properly, probably because they have not been advised how to do that.Generally, when parents brush their child's teeth they are more worried about removing pieces of food than disorganizing biofilm at the stagnation areas.Suitable training in toothbrushing should be provided so that parents become able to recognize visible biofilm, therefore increasing the probability of performing satisfactory biofilm control.

Conclusion
No significant correlations were found between oral hygiene frequency and presence of visible biofilm expressed by the simplified and the conventional indices, which means that oral hygiene frequency was not associated to oral hygiene quality in the evaluated sample.The results indicate that a more specific guidance to parents regarding dental cleaning is needed.More important than tell parents to brush their children's teeth twice or three times a day is to instruct them how to disorganize dental biofilm properly.In addition, the results call the attention for the fact that further studies concerning

Chart 1 -
Visible dental biofilm index* (BF1).0 Absence of visible biofilm.1Thinbiofilm, easily removed, on anterior and/or posterior teeth, visible only after drying with gauze.

Table 5 -
Correlation between oral hygiene frequency and the visible biofilm indices using Spearman's correlation test (n = 90).

Table 4 -
Mean score, standard deviation and range for BF2, which was expressed as a percentage of tooth surfaces with visible biofilm (n = 90).

Table -
Distribution of the sample according to the scores of the simplified visible biofilm index -BF1 (n = 90).
Note: for the scores definition, see Chart 1.

Table 2 -
Products used by parents to clean their child's teeth (n = 90).