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Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren
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Journal of Dental Sciences (2013) xx, 1e7
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ORIGINAL ARTICLE
Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren Hui-Ju Hsieh a,b, Shun-Te Huang c,d*, Chi-Cheng Tsai e, Meng-Jao Chiou f, Cheng-Ta Liao g a
School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan Department of Childhood Education and Nursery, Human Ecology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan c Department of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan d Division of Dentistry for Children and Disabled, Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan e College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan f Taoyuan Township Public Health Center, Kaohsiung County Government, Kaohsiung, Taiwan g Graduate Institute of Oral Health Sciences, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan b
Received 5 January 2012; Final revision received 1 February 2012 Available online - - -
KEYWORDS aboriginal children; dental health; pit-and-fissure sealant; sealant retention
Abstract Background/purpose: The purpose of this study was to evaluate the caries prevention effect of pit-and-fissure sealant application on permanent first molars among Taiwanese aboriginal schoolchildren. Materials and methods: This study included 270 aboriginal school children aged 6e9 years in Southern Taiwan. They were separated into sealant and control groups with follow-up for 1 year. The sealant group (n Z 122) received fissure sealants on healthy, fully erupted first permanent molars; the control group (n Z 148) received an oral examination with no sealant application. Every 6 months, both groups received an oral examination with flashlights, hand-held mirrors, and explorers. Data were analyzed by a Chi-square test, t test, and multiple logistic regression. Results: After 1 year, 14 of the 229 first molars treated with sealants were carious and 60 of the 258 molars in the control group were carious. Sealant application was significantly associated (P < 0.0001) with prevention of tooth decay. The caries rate of the control group was approximately 4-fold higher than that of the sealant group. Conclusion: The application of pit-and-fissure sealants was 94.54% effective in preventing caries on newly erupted permanent molars among Taiwanese aboriginal schoolchildren.
* Corresponding author. Department of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, San Ming District, Kaohsiung 80708, Taiwan. E-mail address: [email protected] (S.-T. Huang). 1991-7902/$36 Copyright ª 2013, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved. http://dx.doi.org/10.1016/j.jds.2013.04.006
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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H.-J. Hsieh et al Complete sealant failure demonstrated a high risk for caries, and such teeth should immediately be resealed. Copyright ª 2013, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.
Introduction Dental caries is a common chronic disease that can cause pain and disability across all age groups. In general, caries on occlusal and buccal/lingual surfaces account for almost 90% of caries experienced by children.1 In 2004, Peressini et al reported that, among 7-year-old children in Ontario, Canada, the majority of dental caries were detected on pitand-fissure surfaces of first molars.2 The occlusal surface of molars is the most vulnerable area to caries in the permanent dentition. As numerous studies have shown,3,4 within a short time after eruption, approximately two-thirds of clinically detected carious lesions are on this surface. In a study from Poland, 11% of 5- to 6-year-old children displayed caries on the occlusal surfaces of permanent first molars, and by 18 years of age, the children displayed caries on 89% of the occlusal surfaces.4 Dental pit-and-fissure sealants are effective in preventing dental caries on occlusal and other pitted and fissured surfaces of the teeth. Sealants have been widely used for more than three decades in preventing the growth of bacteria that promotes decay in premolar and molar pits and fissures.5,6 Pit-and-fissure sealants are underused in Taiwan, particularly among those at high risk of experiencing caries.7 This high-risk population includes children from lower socioeconomic backgrounds and certain ethnic groups.8 Taiwanese aboriginal children often live in remote areas, with less access to dental care, and are reported to have a lower level of dental health than those in nonaboriginal areas.9 Therefore, aboriginal children may have a comparatively higher risk of caries and a lower level of oral-prevention aptitude than children living in nonaboriginal areas. These findings are similar to reports from aboriginal studies in Australia,10,11 Canada,12,13 the US,14 and South Africa.15 In spite of the elevated caries rate among Taiwanese aboriginal children, the efficacy of pit-and-fissure sealants has not been reported in this ethnic group. Therefore, the goal of this study was to investigate the potential benefits of utilizing pit-and-fissure sealants on occlusal surfaces of the first permanent molars among Taiwanese aboriginal children.
Materials and methods Design and sampling This report presents the first year results from a multiyear purposive sampling study in a remote area of Southern Taiwan from 2007 to 2008. The children, aged 6e9 years, attended nine different schools, were randomly selected
(cluster sampling), and were distributed into sealant application and control groups. Parental consent for all participants was obtained according to the human experiment and ethics committee protocol of Chung-Ho Memorial Hospital of Kaohsiung Medical University. Children with systemic diseases, neuromuscular disorders, or physical disabilities were excluded from the project. Pit-and-fissure sealants were applied to the occlusal surfaces of the permanent first molars of first- and secondgrade children in September and October 2007. In the sealant and control groups, 122 and 148 children, respectively, were examined at the baseline. Following sealant application, 1-year-retention checks were performed on second and third graders in September and October 2008.
Oral examination The sealant and control groups received an oral examination every 6 months to detect dental caries. In addition, the retention of pit-and-fissure sealants was evaluated in the sealant group. Subjects were examined by four well-trained licensed dentists using flashlights, hand-held mirrors, and explorers under standardized classroom lighting conditions. Oral examinations were performed according to the principles and methods described by the WHO 4th Oral Health Survey.16 Cohen’s kappa (kappa values of 0.80e0.83) was calculated from paired observations.
Sealant treatment Only fully erupted and healthy (non-carious) first molars were selected for sealant application. Partially erupted molars were not sealed until fully erupted and decayed molars were immediately filled. Molars that were not fully erupted at the onset of the study and received sealants later were not included in the final survey. Each sealant team had its own set of portable dental equipment supplied by the same manufacturer (Sharpgun Dental Manufacturing). Resin-based sealant (3M ESPE, MN, USA) was used and light-cured with a plasma light-curing machine (Dentamerica Asia). The sealing procedure was performed according to instructions of the sealant company. Before sealant application, the teeth were dry-brushed with a toothbrush. The sealing procedure included cleaning the pits and fissures with a rotary prophy brush and pumice, appropriate acid-etching of the occlusal surfaces, sealant application, and light-curing. The dentists attempted to maintain a dry and uncontaminated field using four-handed dentistry, until the sealants were applied and cured. After the dentist had applied the sealants to the appropriate teeth and completed the screenings, the dentists recorded the information on the children’s dental health charts.
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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Evaluation of sealant intervention among aboriginal children
Degree of retention Sealant retention was assessed using a 3-level scale, as follows: (1) complete loss of sealant, i.e., significant loss of sealant from all fissures of a tooth; (2) partial loss of sealant, i.e., partial loss of sealant from the pits or fissures of a tooth; and (3) complete retention, i.e., complete retention of sealant on a tooth.
3 study. This ratio provided the caries protection benefit for each individual child. We also show results of a multivariate logistic regression in our study. A model was designed to explore the correlation between the occurrence of decay (Y), gender (X1), age (X2), and presence of sealant (X3). A database was designed using MS Access, and all statistical tests were performed using JMP 7.0 software utilizing a [?]95% confidence interval (CI).
Statistical analysis
Results A descriptive statistical analysis was performed on the gender, age, and permanent first molar data. First molars which were partially erupted, or not in full occlusion, were classified as unerupted teeth. The decayed, missing, and filled permanent teeth (DMFT), decayed, missing, and filled permanent surface (DMFS), decayed, extracted, and filled primary teeth (deft), and decayed, extracted, and filled primary surface (defs) scores were obtained for all of the children in the study. Data were analyzed using a t test. The number of healthy teeth in the sealant and control groups was established 1 year after sealant application. Total numbers of healthy and decayed teeth were determined by measuring the difference between the baseline and final survey. The percentage of newly decayed teeth was calculated as: (newly decayed teeth/healthy teeth at the baseline) 100%. Data were analyzed with a Chi-square test to compare new decay rates between the sealantapplication and control groups during the 12-month interval. A t test was used to analyze the mean healthy to unhealthy first molar ratios for children in the study at the final survey. Partially erupted or decayed permanent first molars at the baseline examination were excluded from this
Table 1
Table 1 shows results of the baseline examination of schoolchildren aged 6e9 years (mean Z 7.09 0.59 years) in the sealant (n Z 122) and control (n Z 148) groups. In the sealant group, during the time interval from the baseline to the final survey, the difference in the first permanent molar eruption ratio, rose from 70.70% to 89.96%, and the caries ratio [(decay þ filling)/total first molars] rose from 33.62% to 36.67%. In the control group, the difference in the permanent first molar eruption ratio rose from 73.82% to 88.01%, and the caries ratio rose from 40.97% to 48.94%. Table 2 shows that there were no statistical differences between the DMFT or DMFS indices between the sealant and control groups at the baseline. However, in the final survey, the control group had a significantly higher (P Z 0.0342) mean DMFT index (1.74) than the sealant group (1.34). The difference between the means of the groups was 0.4 (95% CI Z 0.37e0.44; P Z 0.0342). The same tendency was found for the DMFS index (P Z 0.0475). Table 3 shows that after excluding first molars that were partially erupted or not in occlusion, 229 first molars received pit-and-fissure sealants. At the final survey, 14 of 229 (6.11%) in the sealant group and 60 of 258 (23.26%) in
Description of children aged 6e9 in remote townships in Taiwan. Sealant group Baseline survey n
Gender Boy 64 Girl 58 Agea (y) 6e7 53 7e8 56 8e9 13 First permanent molars (teeth) Unerupted 143 Erupted 345 Eruption 229 with non-decay Eruption 81 with decay Decayed 35 with filling a
%
Control group Final survey
n
%
Baseline survey n
%
Final survey n
%
52.46 47.54
64 58
52.46 47.54
71 77
47.97 52.03
71 77
47.97 52.03
43.44 45.90 10.66
25 60 37
20.49 49.18 30.33
62 76 10
0.42 0.51 0.07
31 70 47
20.95 47.30 31.76
29.30 70.70 66.38
49 439 278
10.04 89.96 63.33
155 437 258
26.18 73.82 59.04
71 521 266
11.99 88.01 51.06
23.48
118
26.88
98
22.43
145
27.83
10.14
43
9.79
81
18.54
110
21.11
The mean age of study group was 7.09 0.59.
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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H.-J. Hsieh et al Table 2 DMFT, DMFS, deft and defs indexes at baseline and at the final examination in both groups. a Item
Examination Sealant group Control group P Mean SD
DMFTb Baseline Final DMFSc Baseline Final deftd Baseline Final defse Baseline Final
0.95 1.34 1.21 1.70 8.93 8.25 24.25 22.17
Item
Mean SD
1.27 1.23 1.59 1.74 1.86 1.60 2.32 2.26 3.51 9.76 3.29 9.17 12.23 21.50 12.77 21.03
1.45 1.54 2.12 2.33 3.36 3.27 11.25 10.97
Table 4 The ratio of healthy first permanent molars after treatment with pit and fissure sealants at the follow-up survey.
0.0938 0.0342* 0.1108 0.0475* 0.0508 0.0221* 0.0561 0.4287
a
total of 122 children in the sealant group (148 children in the control group) were examined twice. Data analysis was made using a t test. * P < 0.05; ** P < 0.01. b DMFT index: the sum of decayed missing and filled permanent teeth. c DMFS index: the sum of decayed missing and filled permanent dentition surfaces. d deft index: the sum of decayed extracted and filled primary teeth. e defs index: the sum of decayed extracted and filled primary dentition surfaces.
the control group were carious. The Chi-square test revealed that application of sealant was highly significantly associated with prevention of tooth decay (P < 0.0001). The caries rate of the control group was approximately fourfold higher than that of the sealant group. Respective rates of sealant retention, and complete and partial sealant loss were 86.03%, 8.30%, and 5.68%. Results shown in Table 4 indicate that the proportion of healthy permanent first molars in the sealant group (94.54%) was superior to that of the control group (75.15%). The difference between the group ratios was 19.39% (P < 0.0001). Differences in the subject sample sizes observed between the baseline and final surveys resulted because children who were randomly selected to participate in the study might not have had any healthy first molars, or fully erupted first molars to consider in the study. Table 5 reveals that after controlling for gender and age, the multivariate analysis showed that sealants proved to be a significant correlation factor for decay (sealant coefficient Z 1.54; SE Z 0.31; Chi-square Z 24.18; P < 0.0001). The odds ratio (OR) for caries risk among healthy teeth without sealant application was 4.49 (95%
n Ratio of healthy teetha (persons) Mean SD Lower Upper 95% 95%
Sealant 90 group Control 111 group
P
94.54 15.71 91.25 97.83 <0.0001*** 75.15 35.23 68.52 81.78
***P < 0.001. a Healthy teeth: teeth after treatment with pit and fissure sealants show sound.
CI Z 2.48e8.65) compared to the healthy teeth with sealant application.
Discussion In our 2007e2008 study, 6- to 9-year-old aboriginal children demonstrated a lower level of dental health than had previously been reported.7 The prevalence of dental caries was 98.89% (baseline) among the primary dentition and 35.19% among the permanent dentition. The prevalence of primary dentition dental caries among 6-year-old children was 99.08%, higher than in Malaysia (80.9% in 1997), the Philippines (92% in 1999), Australia (43.4% in 2000), Sweden (25% in 2002), and South Africa (60.3% in 1999e2002).17 In our survey, the prevalence of permanent first molar caries among 6- to 9-year-olds was 34.91% (baseline). In 2006, Liu et al reported that the respective caries prevalence rates for permanent first molars in 6- to 14-year-old Taiwanese children in urban, rural, and aboriginal areas were, respectively, 66.67%, 52.38%, and 82.13% (P < 0.0001).9 In addition to the geographic disparities in the dental health status of primary- and high-school children in urban, rural, and aboriginal areas, there was a substantial increase in the caries prevalence rate between younger and older aboriginal age groups.9 Many 6- to 9-year-old aboriginal schoolchildren have insufficient access to dental hygiene instruction and dental treatment, are unskilled in personal oral hygiene care, and may have imbalanced diets.18,19 To minimize geographic disparities and curb the progressive increase in age-related caries prevalence among aboriginal
Table 3 Comparison of healthy first permanent molars after treatment with pit and fissure sealants between the baseline and second survey. Item
Sealant group Control group
n (persons)
122 148
Healthy teeth Baseline
Final
Sealed teeth/sound teeth
Sealed teeth/sound teeth
229 258
215 198
Decayed teeth*
Percentage of decayed teeth
14 60
6.11 23.26
The rate of retention, complete and partial loss were 86.03%, 8.30%, and 5.68%, respectively. *c2 Z 27.666, d.f.Z1, P < 0.0001.
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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Evaluation of sealant intervention among aboriginal children Table 5
Dental caries protection factors at age 6e9 of children in remote townships in Taiwan.
Term
Item
CORa
95% CIb
Gender
Girl Boy 6e7 7e8 8e9 Yes No
1.00 0.98 1.00 0.77 2.28 1.00 4.65
(d d) (0.60 w 1.62 ) (d d) (0.47w1.27) (1.35w3.82) (d d) (2.59w8.91)
Age (y)
Sealant a b c d
5
Pc 0.9461 0.3067 0.0018 <0.0001**
AORd
95% CI
1.00 1.04 1.00 2.41 4.30 1.00 4.49
(d d) (0.62w1.76 ) (d d) (0.98w7.26) (1.69w13.29) (d d) (2.48w8.65)
Pc 0.8718 0.0791 0.0047** <.0001**
COR Z crude odds ratio; data analysis by simple b logistic regression model. 95% CI Z 95% confidence interval. Logistic regression model: dependent variable was the occurrence of decay. * P < 0.05; **P < 0.01. AOR Z adjusted odds ratio; data analysis by multiple c logistic regression model.
children, protective measures of pit-and-fissure sealants on erupting permanent first molars appear to be a public health issue. In this study, sealants were highly effective (94.54%) in preventing dental caries in permanent molar teeth. Fully retained sealants were 100% effective.20,21 Bravo et al22 reported that sealants reduced the incidence of occlusal caries in permanent first molars of children by 76% if reapplied when needed. The prevalence of dental caries normally increases with age,17 but was reduced by 65%, 9 years after the initial treatment with no reapplication during the last 5 years.22 In examining the effectiveness of schoolbased or school-linked dental sealant programs, the Guide to Community Preventive Services reported a 60% decrease in tooth decay on the chewing surfaces of posterior teeth up to 5 years after sealant application.23 In 2002, the Task Force on Community Preventive Services strongly recommended school-based or school-linked sealant programs to prevent and control dental caries.23 In the present study, the caries incidence in the sealant group was 6.11% and in the control group was 23.26%, which demonstrated a significant reduction in the incidence of caries (17.15%) 1 year after the baseline measurements. The effectiveness of protection by sealant application (94.54%) was superior to self-care without sealants (75.15%). Significant findings were observed after 1 year among aboriginal children utilizing our control group design. Study periods of at least 2e3 years are required to assess sealant effectiveness.24 This time frame allows detailed evaluation of retention, sealant leakage, the need for sealant reapplication, and subsequent occlusal and interproximal caries formation. Long-term sealant studies over varying periods were reported. A 10-year study was reported from Canada,25 and a 15-year study from the US.26 In general terms, the retention of sealants is proportionately equated to a reduction in occlusal caries, especially in the first 2 years after application. As time from the initial placement increases, there is a gradual increase in sealant attrition, and accordingly, the sealant’s effectiveness is reduced.27,28 In our 12-month study, sealants were completely lost in 19 teeth (8.30%) and partially lost in 13 teeth (5.68%). Among 229 sealed teeth, the complete retention rate was 86.03%. Teeth that did not lose their sealants, or had partial sealant loss, displayed no decay. Partial sealant loss seldom occurred in the main pits and fissures. Buonocore (1971)29
explained that teeth have extended protection against caries from the retention of resin tags within the superficial enamel despite sealant loss. Among the 19 teeth that completely lost their sealants, 14 were decayed. The caries rate was 14/229 (6.11%) among sealed teeth and 14/19 (73.68%) among sealed teeth that completely lost their sealants. The 13 teeth with partial sealant loss were sound. Our findings indicate that individual teeth with partial loss of sealants are not at a higher risk of developing caries than if they had not received sealants. However, the caries risk for teeth with complete loss of sealants was much higher than those with partial loss. In addition, the 73.68% caries ratio among molars with complete sealant loss was much higher than in the control group and suggests that once the complete loss of a first molar sealant is detected, it must be resealed at once. Sealant application is a technique-sensitive procedure. In this study, there was a relatively high rate of sealant failure that may be attributed to facility and mechanical hindrances. Illumination with flashlights and overhead classroom lighting diminished the effective visualization of the sealant field of view. The air/water syringe and vacuum system were marginal in providing a moisture-free environment during sealant application. In order to minimize the risk of inflicting gingival pain on the 6- to 9-year-old children, rubber dams secured with dental clamps were not utilized to isolate the teeth from oral contamination during sealant application. In addition, to minimize the procedural time associated with sealant application and diminish the risk of creating a fear of dental treatment in the children, anesthetics were not utilized to eliminate discomfort from rubber dam placement during sealant application. The portable dental equipment utilized in this study required the patient to maintain a single supine position, and restricted head movement was helpful for mandibular and maxillary sealant placement. Dental teams contemplating sealant application among aboriginal populations in remote areas should consider the difficulties inherent with portable equipment and facility limitations. Special emphasis should be placed on irrigation and moisture contamination management. Our study had three limitations. First, the process of purposive sampling did not take sample representation into consideration. There are 14 aboriginal tribes in Taiwan, and
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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H.-J. Hsieh et al
this study was conducted in an aboriginal area that consists primarily of Bunun and Paiwan tribal families. Although there is substantial homogeneity in residential characteristics (diet, behavior, and habits) and living environments among the 14 tribes, the results are only representative of Bunun and Paiwan tribes, and extrapolation of the current risk assessment models to the general aboriginal population could be problematic. Second, the process of random sampling (cluster sampling) was unmatched for age and gender, which could result in bias. For this reason, we adjusted for these factors in the multivariate logistic regression. Third, we could not adjust our study using the DMFT index, because the tooth number was utilized as the calculation unit. Furthermore, there was no significant difference in the DMFT index at the baseline between the sealant and control groups. The significant difference appeared only in the second survey. We inferred that this was a consequence of the effectiveness of the sealant. Therefore, the DMFT index was not a confounding factor for adjustment. The bias was minimized in the selection process because the participants were very homogeneous. The sealant and control groups had high levels of homogeneity in their residential characteristics (aboriginal schoolchildren) and living environment (a remote area without dentists). Simultaneously, we used random selection to decrease sampling variations. Inclusion and exclusion criteria in our study were very specific. In conclusion, the 6- to 9-year-old children in this Taiwanese aboriginal area had poor dental health compared to the general population. Ninety-nine percent of the children had caries of the primary dentition. A fourfold decrease in caries was observed in the first permanent molar sealant group compared to the control group, 1 year after sealant application. The elevated sealant failure rate may have been influenced by the tooth isolation techniques, inadequate dental air/water, and vacuum equipment. Complete sealant failure demonstrated a high risk for caries, and such teeth should immediately be resealed.
17.
Acknowledgments
18.
This research was funded by The Health Bureau of Kaohsiung County Government. We would like to thank the participating faculty members at Kaohsiung Medical University (Chun-Chih Chen, Sheng-Hong Wang, Wen-Chia Hu, Ru-Shing Tang, and Chi-Fang Chang). These authors appreciate the staff in the Taoyuan Township Public Health Center, Kaohsiung County Government, and all the teachers, nurses, and the deans of schools in Taoyuan, Mao-Lin, and San-Ming Townships who helped make this project possible.
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Journal of Dental Sciences (2013) xx, 1e7
Available online at www.sciencedirect.com
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ORIGINAL ARTICLE
Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren Hui-Ju Hsieh a,b, Shun-Te Huang c,d*, Chi-Cheng Tsai e, Meng-Jao Chiou f, Cheng-Ta Liao g a
School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan Department of Childhood Education and Nursery, Human Ecology, Chia Nan University of Pharmacy and Science, Tainan, Taiwan c Department of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan d Division of Dentistry for Children and Disabled, Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan e College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan f Taoyuan Township Public Health Center, Kaohsiung County Government, Kaohsiung, Taiwan g Graduate Institute of Oral Health Sciences, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan b
Received 5 January 2012; Final revision received 1 February 2012 Available online - - -
KEYWORDS aboriginal children; dental health; pit-and-fissure sealant; sealant retention
Abstract Background/purpose: The purpose of this study was to evaluate the caries prevention effect of pit-and-fissure sealant application on permanent first molars among Taiwanese aboriginal schoolchildren. Materials and methods: This study included 270 aboriginal school children aged 6e9 years in Southern Taiwan. They were separated into sealant and control groups with follow-up for 1 year. The sealant group (n Z 122) received fissure sealants on healthy, fully erupted first permanent molars; the control group (n Z 148) received an oral examination with no sealant application. Every 6 months, both groups received an oral examination with flashlights, hand-held mirrors, and explorers. Data were analyzed by a Chi-square test, t test, and multiple logistic regression. Results: After 1 year, 14 of the 229 first molars treated with sealants were carious and 60 of the 258 molars in the control group were carious. Sealant application was significantly associated (P < 0.0001) with prevention of tooth decay. The caries rate of the control group was approximately 4-fold higher than that of the sealant group. Conclusion: The application of pit-and-fissure sealants was 94.54% effective in preventing caries on newly erupted permanent molars among Taiwanese aboriginal schoolchildren.
* Corresponding author. Department of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, San Ming District, Kaohsiung 80708, Taiwan. E-mail address: [email protected] (S.-T. Huang). 1991-7902/$36 Copyright ª 2013, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved. http://dx.doi.org/10.1016/j.jds.2013.04.006
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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H.-J. Hsieh et al Complete sealant failure demonstrated a high risk for caries, and such teeth should immediately be resealed. Copyright ª 2013, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.
Introduction Dental caries is a common chronic disease that can cause pain and disability across all age groups. In general, caries on occlusal and buccal/lingual surfaces account for almost 90% of caries experienced by children.1 In 2004, Peressini et al reported that, among 7-year-old children in Ontario, Canada, the majority of dental caries were detected on pitand-fissure surfaces of first molars.2 The occlusal surface of molars is the most vulnerable area to caries in the permanent dentition. As numerous studies have shown,3,4 within a short time after eruption, approximately two-thirds of clinically detected carious lesions are on this surface. In a study from Poland, 11% of 5- to 6-year-old children displayed caries on the occlusal surfaces of permanent first molars, and by 18 years of age, the children displayed caries on 89% of the occlusal surfaces.4 Dental pit-and-fissure sealants are effective in preventing dental caries on occlusal and other pitted and fissured surfaces of the teeth. Sealants have been widely used for more than three decades in preventing the growth of bacteria that promotes decay in premolar and molar pits and fissures.5,6 Pit-and-fissure sealants are underused in Taiwan, particularly among those at high risk of experiencing caries.7 This high-risk population includes children from lower socioeconomic backgrounds and certain ethnic groups.8 Taiwanese aboriginal children often live in remote areas, with less access to dental care, and are reported to have a lower level of dental health than those in nonaboriginal areas.9 Therefore, aboriginal children may have a comparatively higher risk of caries and a lower level of oral-prevention aptitude than children living in nonaboriginal areas. These findings are similar to reports from aboriginal studies in Australia,10,11 Canada,12,13 the US,14 and South Africa.15 In spite of the elevated caries rate among Taiwanese aboriginal children, the efficacy of pit-and-fissure sealants has not been reported in this ethnic group. Therefore, the goal of this study was to investigate the potential benefits of utilizing pit-and-fissure sealants on occlusal surfaces of the first permanent molars among Taiwanese aboriginal children.
Materials and methods Design and sampling This report presents the first year results from a multiyear purposive sampling study in a remote area of Southern Taiwan from 2007 to 2008. The children, aged 6e9 years, attended nine different schools, were randomly selected
(cluster sampling), and were distributed into sealant application and control groups. Parental consent for all participants was obtained according to the human experiment and ethics committee protocol of Chung-Ho Memorial Hospital of Kaohsiung Medical University. Children with systemic diseases, neuromuscular disorders, or physical disabilities were excluded from the project. Pit-and-fissure sealants were applied to the occlusal surfaces of the permanent first molars of first- and secondgrade children in September and October 2007. In the sealant and control groups, 122 and 148 children, respectively, were examined at the baseline. Following sealant application, 1-year-retention checks were performed on second and third graders in September and October 2008.
Oral examination The sealant and control groups received an oral examination every 6 months to detect dental caries. In addition, the retention of pit-and-fissure sealants was evaluated in the sealant group. Subjects were examined by four well-trained licensed dentists using flashlights, hand-held mirrors, and explorers under standardized classroom lighting conditions. Oral examinations were performed according to the principles and methods described by the WHO 4th Oral Health Survey.16 Cohen’s kappa (kappa values of 0.80e0.83) was calculated from paired observations.
Sealant treatment Only fully erupted and healthy (non-carious) first molars were selected for sealant application. Partially erupted molars were not sealed until fully erupted and decayed molars were immediately filled. Molars that were not fully erupted at the onset of the study and received sealants later were not included in the final survey. Each sealant team had its own set of portable dental equipment supplied by the same manufacturer (Sharpgun Dental Manufacturing). Resin-based sealant (3M ESPE, MN, USA) was used and light-cured with a plasma light-curing machine (Dentamerica Asia). The sealing procedure was performed according to instructions of the sealant company. Before sealant application, the teeth were dry-brushed with a toothbrush. The sealing procedure included cleaning the pits and fissures with a rotary prophy brush and pumice, appropriate acid-etching of the occlusal surfaces, sealant application, and light-curing. The dentists attempted to maintain a dry and uncontaminated field using four-handed dentistry, until the sealants were applied and cured. After the dentist had applied the sealants to the appropriate teeth and completed the screenings, the dentists recorded the information on the children’s dental health charts.
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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Evaluation of sealant intervention among aboriginal children
Degree of retention Sealant retention was assessed using a 3-level scale, as follows: (1) complete loss of sealant, i.e., significant loss of sealant from all fissures of a tooth; (2) partial loss of sealant, i.e., partial loss of sealant from the pits or fissures of a tooth; and (3) complete retention, i.e., complete retention of sealant on a tooth.
3 study. This ratio provided the caries protection benefit for each individual child. We also show results of a multivariate logistic regression in our study. A model was designed to explore the correlation between the occurrence of decay (Y), gender (X1), age (X2), and presence of sealant (X3). A database was designed using MS Access, and all statistical tests were performed using JMP 7.0 software utilizing a [?]95% confidence interval (CI).
Statistical analysis
Results A descriptive statistical analysis was performed on the gender, age, and permanent first molar data. First molars which were partially erupted, or not in full occlusion, were classified as unerupted teeth. The decayed, missing, and filled permanent teeth (DMFT), decayed, missing, and filled permanent surface (DMFS), decayed, extracted, and filled primary teeth (deft), and decayed, extracted, and filled primary surface (defs) scores were obtained for all of the children in the study. Data were analyzed using a t test. The number of healthy teeth in the sealant and control groups was established 1 year after sealant application. Total numbers of healthy and decayed teeth were determined by measuring the difference between the baseline and final survey. The percentage of newly decayed teeth was calculated as: (newly decayed teeth/healthy teeth at the baseline) 100%. Data were analyzed with a Chi-square test to compare new decay rates between the sealantapplication and control groups during the 12-month interval. A t test was used to analyze the mean healthy to unhealthy first molar ratios for children in the study at the final survey. Partially erupted or decayed permanent first molars at the baseline examination were excluded from this
Table 1
Table 1 shows results of the baseline examination of schoolchildren aged 6e9 years (mean Z 7.09 0.59 years) in the sealant (n Z 122) and control (n Z 148) groups. In the sealant group, during the time interval from the baseline to the final survey, the difference in the first permanent molar eruption ratio, rose from 70.70% to 89.96%, and the caries ratio [(decay þ filling)/total first molars] rose from 33.62% to 36.67%. In the control group, the difference in the permanent first molar eruption ratio rose from 73.82% to 88.01%, and the caries ratio rose from 40.97% to 48.94%. Table 2 shows that there were no statistical differences between the DMFT or DMFS indices between the sealant and control groups at the baseline. However, in the final survey, the control group had a significantly higher (P Z 0.0342) mean DMFT index (1.74) than the sealant group (1.34). The difference between the means of the groups was 0.4 (95% CI Z 0.37e0.44; P Z 0.0342). The same tendency was found for the DMFS index (P Z 0.0475). Table 3 shows that after excluding first molars that were partially erupted or not in occlusion, 229 first molars received pit-and-fissure sealants. At the final survey, 14 of 229 (6.11%) in the sealant group and 60 of 258 (23.26%) in
Description of children aged 6e9 in remote townships in Taiwan. Sealant group Baseline survey n
Gender Boy 64 Girl 58 Agea (y) 6e7 53 7e8 56 8e9 13 First permanent molars (teeth) Unerupted 143 Erupted 345 Eruption 229 with non-decay Eruption 81 with decay Decayed 35 with filling a
%
Control group Final survey
n
%
Baseline survey n
%
Final survey n
%
52.46 47.54
64 58
52.46 47.54
71 77
47.97 52.03
71 77
47.97 52.03
43.44 45.90 10.66
25 60 37
20.49 49.18 30.33
62 76 10
0.42 0.51 0.07
31 70 47
20.95 47.30 31.76
29.30 70.70 66.38
49 439 278
10.04 89.96 63.33
155 437 258
26.18 73.82 59.04
71 521 266
11.99 88.01 51.06
23.48
118
26.88
98
22.43
145
27.83
10.14
43
9.79
81
18.54
110
21.11
The mean age of study group was 7.09 0.59.
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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H.-J. Hsieh et al Table 2 DMFT, DMFS, deft and defs indexes at baseline and at the final examination in both groups. a Item
Examination Sealant group Control group P Mean SD
DMFTb Baseline Final DMFSc Baseline Final deftd Baseline Final defse Baseline Final
0.95 1.34 1.21 1.70 8.93 8.25 24.25 22.17
Item
Mean SD
1.27 1.23 1.59 1.74 1.86 1.60 2.32 2.26 3.51 9.76 3.29 9.17 12.23 21.50 12.77 21.03
1.45 1.54 2.12 2.33 3.36 3.27 11.25 10.97
Table 4 The ratio of healthy first permanent molars after treatment with pit and fissure sealants at the follow-up survey.
0.0938 0.0342* 0.1108 0.0475* 0.0508 0.0221* 0.0561 0.4287
a
total of 122 children in the sealant group (148 children in the control group) were examined twice. Data analysis was made using a t test. * P < 0.05; ** P < 0.01. b DMFT index: the sum of decayed missing and filled permanent teeth. c DMFS index: the sum of decayed missing and filled permanent dentition surfaces. d deft index: the sum of decayed extracted and filled primary teeth. e defs index: the sum of decayed extracted and filled primary dentition surfaces.
the control group were carious. The Chi-square test revealed that application of sealant was highly significantly associated with prevention of tooth decay (P < 0.0001). The caries rate of the control group was approximately fourfold higher than that of the sealant group. Respective rates of sealant retention, and complete and partial sealant loss were 86.03%, 8.30%, and 5.68%. Results shown in Table 4 indicate that the proportion of healthy permanent first molars in the sealant group (94.54%) was superior to that of the control group (75.15%). The difference between the group ratios was 19.39% (P < 0.0001). Differences in the subject sample sizes observed between the baseline and final surveys resulted because children who were randomly selected to participate in the study might not have had any healthy first molars, or fully erupted first molars to consider in the study. Table 5 reveals that after controlling for gender and age, the multivariate analysis showed that sealants proved to be a significant correlation factor for decay (sealant coefficient Z 1.54; SE Z 0.31; Chi-square Z 24.18; P < 0.0001). The odds ratio (OR) for caries risk among healthy teeth without sealant application was 4.49 (95%
n Ratio of healthy teetha (persons) Mean SD Lower Upper 95% 95%
Sealant 90 group Control 111 group
P
94.54 15.71 91.25 97.83 <0.0001*** 75.15 35.23 68.52 81.78
***P < 0.001. a Healthy teeth: teeth after treatment with pit and fissure sealants show sound.
CI Z 2.48e8.65) compared to the healthy teeth with sealant application.
Discussion In our 2007e2008 study, 6- to 9-year-old aboriginal children demonstrated a lower level of dental health than had previously been reported.7 The prevalence of dental caries was 98.89% (baseline) among the primary dentition and 35.19% among the permanent dentition. The prevalence of primary dentition dental caries among 6-year-old children was 99.08%, higher than in Malaysia (80.9% in 1997), the Philippines (92% in 1999), Australia (43.4% in 2000), Sweden (25% in 2002), and South Africa (60.3% in 1999e2002).17 In our survey, the prevalence of permanent first molar caries among 6- to 9-year-olds was 34.91% (baseline). In 2006, Liu et al reported that the respective caries prevalence rates for permanent first molars in 6- to 14-year-old Taiwanese children in urban, rural, and aboriginal areas were, respectively, 66.67%, 52.38%, and 82.13% (P < 0.0001).9 In addition to the geographic disparities in the dental health status of primary- and high-school children in urban, rural, and aboriginal areas, there was a substantial increase in the caries prevalence rate between younger and older aboriginal age groups.9 Many 6- to 9-year-old aboriginal schoolchildren have insufficient access to dental hygiene instruction and dental treatment, are unskilled in personal oral hygiene care, and may have imbalanced diets.18,19 To minimize geographic disparities and curb the progressive increase in age-related caries prevalence among aboriginal
Table 3 Comparison of healthy first permanent molars after treatment with pit and fissure sealants between the baseline and second survey. Item
Sealant group Control group
n (persons)
122 148
Healthy teeth Baseline
Final
Sealed teeth/sound teeth
Sealed teeth/sound teeth
229 258
215 198
Decayed teeth*
Percentage of decayed teeth
14 60
6.11 23.26
The rate of retention, complete and partial loss were 86.03%, 8.30%, and 5.68%, respectively. *c2 Z 27.666, d.f.Z1, P < 0.0001.
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Evaluation of sealant intervention among aboriginal children Table 5
Dental caries protection factors at age 6e9 of children in remote townships in Taiwan.
Term
Item
CORa
95% CIb
Gender
Girl Boy 6e7 7e8 8e9 Yes No
1.00 0.98 1.00 0.77 2.28 1.00 4.65
(d d) (0.60 w 1.62 ) (d d) (0.47w1.27) (1.35w3.82) (d d) (2.59w8.91)
Age (y)
Sealant a b c d
5
Pc 0.9461 0.3067 0.0018 <0.0001**
AORd
95% CI
1.00 1.04 1.00 2.41 4.30 1.00 4.49
(d d) (0.62w1.76 ) (d d) (0.98w7.26) (1.69w13.29) (d d) (2.48w8.65)
Pc 0.8718 0.0791 0.0047** <.0001**
COR Z crude odds ratio; data analysis by simple b logistic regression model. 95% CI Z 95% confidence interval. Logistic regression model: dependent variable was the occurrence of decay. * P < 0.05; **P < 0.01. AOR Z adjusted odds ratio; data analysis by multiple c logistic regression model.
children, protective measures of pit-and-fissure sealants on erupting permanent first molars appear to be a public health issue. In this study, sealants were highly effective (94.54%) in preventing dental caries in permanent molar teeth. Fully retained sealants were 100% effective.20,21 Bravo et al22 reported that sealants reduced the incidence of occlusal caries in permanent first molars of children by 76% if reapplied when needed. The prevalence of dental caries normally increases with age,17 but was reduced by 65%, 9 years after the initial treatment with no reapplication during the last 5 years.22 In examining the effectiveness of schoolbased or school-linked dental sealant programs, the Guide to Community Preventive Services reported a 60% decrease in tooth decay on the chewing surfaces of posterior teeth up to 5 years after sealant application.23 In 2002, the Task Force on Community Preventive Services strongly recommended school-based or school-linked sealant programs to prevent and control dental caries.23 In the present study, the caries incidence in the sealant group was 6.11% and in the control group was 23.26%, which demonstrated a significant reduction in the incidence of caries (17.15%) 1 year after the baseline measurements. The effectiveness of protection by sealant application (94.54%) was superior to self-care without sealants (75.15%). Significant findings were observed after 1 year among aboriginal children utilizing our control group design. Study periods of at least 2e3 years are required to assess sealant effectiveness.24 This time frame allows detailed evaluation of retention, sealant leakage, the need for sealant reapplication, and subsequent occlusal and interproximal caries formation. Long-term sealant studies over varying periods were reported. A 10-year study was reported from Canada,25 and a 15-year study from the US.26 In general terms, the retention of sealants is proportionately equated to a reduction in occlusal caries, especially in the first 2 years after application. As time from the initial placement increases, there is a gradual increase in sealant attrition, and accordingly, the sealant’s effectiveness is reduced.27,28 In our 12-month study, sealants were completely lost in 19 teeth (8.30%) and partially lost in 13 teeth (5.68%). Among 229 sealed teeth, the complete retention rate was 86.03%. Teeth that did not lose their sealants, or had partial sealant loss, displayed no decay. Partial sealant loss seldom occurred in the main pits and fissures. Buonocore (1971)29
explained that teeth have extended protection against caries from the retention of resin tags within the superficial enamel despite sealant loss. Among the 19 teeth that completely lost their sealants, 14 were decayed. The caries rate was 14/229 (6.11%) among sealed teeth and 14/19 (73.68%) among sealed teeth that completely lost their sealants. The 13 teeth with partial sealant loss were sound. Our findings indicate that individual teeth with partial loss of sealants are not at a higher risk of developing caries than if they had not received sealants. However, the caries risk for teeth with complete loss of sealants was much higher than those with partial loss. In addition, the 73.68% caries ratio among molars with complete sealant loss was much higher than in the control group and suggests that once the complete loss of a first molar sealant is detected, it must be resealed at once. Sealant application is a technique-sensitive procedure. In this study, there was a relatively high rate of sealant failure that may be attributed to facility and mechanical hindrances. Illumination with flashlights and overhead classroom lighting diminished the effective visualization of the sealant field of view. The air/water syringe and vacuum system were marginal in providing a moisture-free environment during sealant application. In order to minimize the risk of inflicting gingival pain on the 6- to 9-year-old children, rubber dams secured with dental clamps were not utilized to isolate the teeth from oral contamination during sealant application. In addition, to minimize the procedural time associated with sealant application and diminish the risk of creating a fear of dental treatment in the children, anesthetics were not utilized to eliminate discomfort from rubber dam placement during sealant application. The portable dental equipment utilized in this study required the patient to maintain a single supine position, and restricted head movement was helpful for mandibular and maxillary sealant placement. Dental teams contemplating sealant application among aboriginal populations in remote areas should consider the difficulties inherent with portable equipment and facility limitations. Special emphasis should be placed on irrigation and moisture contamination management. Our study had three limitations. First, the process of purposive sampling did not take sample representation into consideration. There are 14 aboriginal tribes in Taiwan, and
Please cite this article in press as: Hsieh H-J, et al., Evaluation of a sealant intervention program among Taiwanese aboriginal schoolchildren, Journal of Dental Sciences (2013), http://dx.doi.org/10.1016/j.jds.2013.04.006
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H.-J. Hsieh et al
this study was conducted in an aboriginal area that consists primarily of Bunun and Paiwan tribal families. Although there is substantial homogeneity in residential characteristics (diet, behavior, and habits) and living environments among the 14 tribes, the results are only representative of Bunun and Paiwan tribes, and extrapolation of the current risk assessment models to the general aboriginal population could be problematic. Second, the process of random sampling (cluster sampling) was unmatched for age and gender, which could result in bias. For this reason, we adjusted for these factors in the multivariate logistic regression. Third, we could not adjust our study using the DMFT index, because the tooth number was utilized as the calculation unit. Furthermore, there was no significant difference in the DMFT index at the baseline between the sealant and control groups. The significant difference appeared only in the second survey. We inferred that this was a consequence of the effectiveness of the sealant. Therefore, the DMFT index was not a confounding factor for adjustment. The bias was minimized in the selection process because the participants were very homogeneous. The sealant and control groups had high levels of homogeneity in their residential characteristics (aboriginal schoolchildren) and living environment (a remote area without dentists). Simultaneously, we used random selection to decrease sampling variations. Inclusion and exclusion criteria in our study were very specific. In conclusion, the 6- to 9-year-old children in this Taiwanese aboriginal area had poor dental health compared to the general population. Ninety-nine percent of the children had caries of the primary dentition. A fourfold decrease in caries was observed in the first permanent molar sealant group compared to the control group, 1 year after sealant application. The elevated sealant failure rate may have been influenced by the tooth isolation techniques, inadequate dental air/water, and vacuum equipment. Complete sealant failure demonstrated a high risk for caries, and such teeth should immediately be resealed.
17.
Acknowledgments
18.
This research was funded by The Health Bureau of Kaohsiung County Government. We would like to thank the participating faculty members at Kaohsiung Medical University (Chun-Chih Chen, Sheng-Hong Wang, Wen-Chia Hu, Ru-Shing Tang, and Chi-Fang Chang). These authors appreciate the staff in the Taoyuan Township Public Health Center, Kaohsiung County Government, and all the teachers, nurses, and the deans of schools in Taoyuan, Mao-Lin, and San-Ming Townships who helped make this project possible.
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