ABSTRACT. This study was conducted to examine the oral condition and the salivary and microbiological parameters associated with dental caries in 62.
Maria Teresa Botti Rodrigues dos Santos, DDSc, PhD Danilo Masiero, MD 2, Maria DDSc, Regina PhD 3* Lorenzetti Simionato,
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Risk factors for dental caries in children with cerebral palsy
'Division of Dentistry for Persons with Disabilities, University Cruzeiro do Sul of SIo Paulo, Brazil 2Federal University of SIo Paulo. Brazil; Department of Microbiology, Institute of Biomedical Sciences, University of S I o Paulo, S I o Paulo, Brazil CEP05508-900; *corresponding author, mrsimion @icb.usp.br
Spec Care Dentist 22 (3):103-107, 2002
ABSTRACT
INTRODUCTION
This study was conducted to examine the oral condition and the salivary and microbiological parameters associated with dental caries in 6 2 children with cerebral palsy, who c a m e from households of low socioeconomic status (Study Group). This group had mixed (6 to 11 years old) and permanent ( 1 1 to 16 years old) dentition. Dental examinations were performed to measure dental caries, plaque index, salivary levels of mutans streptococci and lactobacilli, salivary flow rate, pH of stimulated saliva, and buffer capacity of saliva. A group of 67 non-handicapped children from similar socioeconomic backgrounds also were examined using these parameters (Control Group). Data were analyzed statistically by nonparametric tests and by correlation. The results showed that children with cerebral palsy who had permanent dentitions had a higher mean decayed, missing and filled surfaces index, as well as a higher p l a q u e index f o r both s e x e s . Microbiological examination revealed higher levels of mutans streptococci among Study Group subjects with mixed dentition than in the Control Group. Also, lactobacillus counts were higher in the Study Group, regardless of sex or dentition. With r e s p e c t t o salivary f l o w rate, p H and buffering capacity, lower mean values w e r e obtained for the Study Group.
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KEY WORDS: dental caries, risk factors, cerebral palsy and children
lthough caries prevalence overall has declined, a significant portion of c h i l d r e n with c e r e b r a l palsy remain a t high risk f o r c a r i e s development.'-* The a priori identification of individuals at high risk of caries would be of considerable importance in allocating resources to caries prevention. The importance of Streptococcus mutans in the initiation of dental decay has been extensively studied.j Since S. mutans and lactobacilli have been implicated directly in the initiation and progression of dental caries, these organisms have been used to assess caries risk in a number of s t ~ i d i e s . The ~.~ associations of mutans streptococci and lactobacilli with the prevalence of dental caries have been studied throughout the world,6-g but relatively few studies have addressed the problem in Brazil and none has addressed the issue in children with cerebral palsy. Salivary factors also have been related to the degree of caries activity.' Buffer capacity, in particular, has been correlated with caries activity.'" In addition, salivary pH" and secretion rateI2 seem to influence caries susceptibility. This article reports on a cross-sectional study designed to assess risk factors associated with caries activity in children with and without cerebral palsy in Siio Paulo, Brazil. The variables measured in these children were microbial factors, plaque index and salivary conditions.
MATERIALS AND METHODS Subjects studied and data collection A total of 62 children with cerebral palsy (35 males and 27 females) with low socioeconomic status, who were dental patients at Lar Escola Siio Francisco - Rehabilitation Center of the Federal University of Siio Paulo, constituted the Study Group. Thirty-four of the children were aged 6 to 1 1 years and had a mixed dentition, and 28 were aged 12 to 16 years and had a permanent dentition. The Control Group was composed of 67 children (42 males and 25 females), who attended a regular school in Siio Paulo, were of similar socioeconomic background, and who did not have cerebral palsy. Thirty-seven of these children were aged 6 to 1 1 years and had a mixed dentition, and 30 were aged 12 to 16 years and had a permanent dentition. Written parental consent was obtained for all children before data collection Caries experience was expressed as decayed, missing and filled surfaces (dmfs for primary dentition, DMFS for permanent dentition). Salivary flow rate, pH of stimulated saliva and buffer capacity were determined. Salivary levels of mutans streptococci and lactobacilli were measured from the mean number of colony forming units per milliliter. Subjects also were examined for plaque accumulation.
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Caries prevalence The oral health status of all subjects was recorded during an examination conducted by the same dentist (MTBRS) in a dental office. All clinical examinations for dental caries were performed on teeth dried with air, and the surfaces of the teeth were examined with the help of a mirror, blunt probe and artificial light. Caries diagnosis was performed according to standard World Health Organization methodology,I3 with dmfs or DMFS being recorded and the scores calculated. Salivary analysis Saliva samples were collected at the dental office two hours after breakfast. Stimulated salivary secretion rate was determined by asking the subject to hold in hislher mouth a piece of base gum that was flavored but sugar-free until it became soft, and to swallow saliva produced during that time. Subsequently, the subject was asked to expectorate all saliva formed over a 5-minute period into a graduated sterile tube. The secretion rate was estimated as milliliters (mls) per minute, and pH was immediately determined with a portable pH meter (Denver Instruments, Arvada, CO). To estimate buffering capacity, 3 ml of 0.005 N HCI solution were added to 1 ml of saliva.14 The sample was shaken, and the stopper was then removed to eliminate carbon dioxide. The sample was allowed to stand for 10 minutes, and the final pH was measured with the portable pH meter.
Determination of mutans streptococci The salivary levels of mutans streptococci were determined by the practical method of Kohler and Bratthall.ls Briefly, saliva was stimulated with a base gum, and a sample was collected with a sterile wooden spatula that was dipped 10 times in the saliva which had accumulated in the floor of the mouth. Each side of the spatula was then pressed onto the convex surface of MSB agar (Mitis Salivaryius Agar with 15% sucrose and 3.3 milligrams of bacitracin per liter)I6 on a Rodac plate (Difco Laboratories) to grow mutans streptococci. The MSB agar plates were incubated inside sealed plastic bags with air at 37°C for 48 hours (h). The number of organisms in a predetermined area ( 1.5 centimeters2 [cm2]) that exhibited typical morphological characteristics of mutans streptococci were counted using a stereoscopic microscope. The number of colony forming units per milliliter (cfulml) was then calculated. Determination of lactobacilli T h e stimulated saliva samples were diluted in 0.01 M phosphate buffer and at pH 7.0. Under aseptic technique, 25 microliters of each dilution was inoculated in triplicate on the surface of Rogosa SL Agar (Difco Laboratories), which is selective for lactobacilli, using the micro-method of Westergreen and Krasse." After the inoculum dried, another layer of Rogosa medium was poured over the surface of the culture to allow growth inside the medium. The Rogosa SL Agar plates were incubated aerobically at 37°C for 72 h. The mean number of colony forming units per milliliter of lactobacilli were calculated.
Spec Care Dentist 22(3) 2002
Plaque index The plaque index was determined as described by Podshadley and Haley." A disclosing solution (erythrosin) was used to visualize plaque-coated surfaces. After rinsing with water, the surfaces were examined for plaque. The number of surfaces on which plaque was present was recorded. No attempt was made to differentiate between varying amounts of plaque on tooth surfaces. The examination was performed on the following teeth in this order: 1) maxillary right first molar, 2) maxillary right central incisor, 3) maxillary left first molar, 4) mandibular left first molar, 5 ) mandibular left central incisor, 6) mandibular right first molar. The tooth surfaces assessed were the buccal surfaces of the mandibular molars and the labial surfaces of the maxillary and mandibular incisors. T o assess the plaque accumulation on each surface, the examiner mentally divided the tooth into five sections. The plaque score for the designated surfaces was calculated by dividing the sum of the scores by the number of surfaces charted. Statistical analysis All statistical analyses were performed using nonparametric tests.I9 The Wilcoxon-Mann-Whitney test was used to compare variables across the sexes, dentition (mixed and permanent) and groups (Study and Control). Spearman's correlation coefficients were computed between all seven variables of this study for both groups. A level of significance of .05 was used for all tests.
RESULTS The results (mean values f SD) of the variables-DMFS or dmfs, salivary analysis (flow rate, pH and buffering capacity), microbial counts (mutans streptococci x lo5 cfu/ml and lactobacilli x lo5 cfulml), and plaque index-for the Study and Control Groups are presented in Tables 1 and 2. Significantly higher DMFS index values were observed for males ( p < .01) and females ( p < .05) with a permanent dentition in the Study Group compared with the Control Group. Similarly, significantly higher plaque index values were observed for males (p < .001) and females (p < .05) with a permanent dentition in the Study Group. Mutans streptococci were present in significantly higher numbers only among females with a mixed dentition (p < .05) in the Study Group. An evaluation of the saliva collected is shown in Table 2. Salivary flow rates in the Study Group were found to be significantly lower (p < ,001) in all children with mixed or permanent dentitions except for females with a permanent dentition. Table 2 also shows that pH was significantly lower in the Study Group, in all subjects, except for males with a permanent dentition. No differences were found in any group with regard to buffering capacity of the stimulated saliva.
DISCUSSION The purpose of this study was to evaluate selected variables associated with dental caries in children with cerebral palsy and compare them with children who did not have a disability.
Spec Care Dentist 22(3) 2002
Caries in Children with Cerebral Palsy
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These data could be used to develop caries Table 1. Mean ( 4 D ) values for DMFS, plaque index, streptococci and lactobacilli for prevention programs for children at risk, for children with and without ceberal palsy. example, by teaching the need to control the DMFS amount and frequency of sugar intake, providing fluoride therapy, or encouraging Dentition Sex Study Group Control Group p the use of anti-plaque agents in mouth Mixed M 7.65 (i 10.32) 7.82 (i 9.37) .95 rinses or toothpastes. F 6.18 (i 7.38) .42 3.93 (i 6.50) We found differences between the mean Permanent M 17.58 (+ 24.12) 3.25 (i 3.75) c.01 DMFS scores for the two groups, with the F 9.31(+ 10.40)
