Does the classification of cerebral palsy influence caries experience in children and adolescents?

Abstract

AIM:

To evaluate the influence of the classification of cerebral palsy CP on the caries experience in children and adolescents, and determine the types of teeth most affected by dental caries.

METHODS:

A total of 181 individuals with CP, aged 8.30±4.10 years were examined for dental caries diagnosis in primary, mixed and permanent dentitions. The sample consisted of 96 quadriplegic individuals, 56 diplegic, 18 hemiplegic and 11 with choreoathetosis. The groups were compared using Kruskal-Wallis and Chi-square tests. Univariate logistic regression models were used to identify whether age was a predictor of caries risk α=5%.

RESULTS:

The sample was homogeneous as regards sex and age, among patients with quadriplegia, diplegia, hemiplegia and choreoathetosis. Out of the total sample, 51.4% of the individuals were caries free. The overall mean for the dmft and DMFT indices were 1.70±3.30 and 0.70±1.60, respectively. The mean caries experience in primary, mixed and permanent dentitions did not vary significantly according to the CP classification p>0.05. Child´s age was a predictor for dental caries experience p<0.05.

CONCLUSIONS:

The CP classification did not influence on caries experience, and the teeth most affected by dental caries were the primary and first permanent molars.

dental caries; cerebral palsy; oral hygiene; preventive dentistry

Introduction

Cerebral palsy CP describes a group of permanent disorders involving movement and posture development that cause activity limitations. These are attributed to nonprogressive disturbances occurring in the developing fetal or infant brain. CP motor disorders are often accompanied by epilepsy, secondary musculoskeletal problems and disturbances of sensation, perception, cognition, communication and behavior. This condition is the most common cause of severe physical disability in childhood^{1 - 2}.

The type of abnormal resting muscle tone or involuntary movement disorder observed or elicited is usually assumed to be related to the underlying pathophysiology of the condition. Individuals with spastic cerebral palsy present increased tone, pathological reflexes and hyperreflexia or pyramidal signs, with clinical patterns of involvement including: quadriplegia, more severe motor involvement of all four limbs; diplegia, involvement of corresponding limbs, although typically more severe in the legs; and hemiplegia, affecting one side. Individuals with dyskinesia choreoathetosis present involuntary, uncontrolled, recurring and occasionally stereotyped movements, which may be totally disabling when severe³.

Dental caries is an oral health burden in individuals with CP, not only in primary but also in permanent dentition, with higher percentages of decayed and missing teeth^{4 - 5}. Children with CP can present a reduced unstimulated salivary flow rate, pH and buffer capacity, which may compromise the protective function of saliva, resulting in increased risk of oral diseases⁶.

Maintaining the oral health of individuals with CP requires systematic hygiene practices that demand supervision, or their oral hygiene may eventually have to be performed by family caregivers. A child's development needs the family's participation, involvement and support. When this is well-structured, it will positively contribute to the child's quality of life. However, in individuals with CP, this process of participation, involvement and support is not restricted to the developmental period. The task of taking care of a child with complex disabilities at home may be somewhat daunting for caregivers, and may reflect the way in which these individuals are cared for^{5 , 7}

The purposes of this study were to assess the influence of the classification of CP on caries experience in children and adolescents, and determine the type of teeth most affected by dental caries. The null hypothesis is that the classification of CP does not influence on caries experience in children and adolescents.

Material and methods

This cross-sectional study was approved by the Human Research Ethics Committee of the Cruzeiro do Sul University, Protocol No. 152/2011, and was conducted in accordance with the ethical standards stated in the Declaration of Helsinki.

To calculate the sample size, the used formula considered a confidence interval of 95%, statistical power of 80%, mean caries prevalence of 5.43, standard deviation of 4.17 and a mean minimum difference of 4.56 to be detected⁸. Thus, a minimum of 181 individuals was required.

The sample consisted of non-institutionalized children and adolescents 110 male and 71 female presenting a medical diagnosis of CP, age-range from 1 to 17 years mean age, 8.30±4.10, and participating in a prevention-based program for oral health. The study was conducted in the State of São Paulo, Brazil, in a rehabilitation centre between April and December 2011. Written informed consent for participation and publication was obtained from the parents or guardians of each individual with CP, who agreed to participate in the study.

Patient medical records were reviewed for clinical data, including gender, age and CP classification choreoathetosis, quadriplegia, diplegia or hemiplegia.

A single calibrated examiner weighted Kappa=0.89 conducted the oral examination with the help of an assistant to record the data. Before clinical examination, professional tooth cleaning was performed in each patient. The patients' teeth were assessed under a reflector light using a dental mirror and a probe after drying with a 3-in-1 syringe. The World Health Organization criteria⁹ were used for recording dental caries experience by the decayed, missing and filled teeth index, using the dmft and DMFT indices for primary and permanent dentition, respectively. In children with mixed dentition, dmft and DMFT were recorded together. No radiographic examination was performed.

Statistical Analysis

Descriptive statistical tests were used to assess the demographic data using SPSS software program Statistics Package for Social Science, version 15.0 for Windows. The measures of central tendency mean and dispersion standard deviation were used for continuous variables. Participants were divided into groups according to their clinical type of CP: choreoathetosis n=11; quadriplegia n=96; diplegia n=56; and hemiplegia n=18. The nonparametric Chi-square and Kruskal-Wallis tests were used to determine significant differences in data.

The teeth most affected by dental caries in primary and permanent dentitions were assessed for subsequent regression analysis. Univariate logistic regression models were used to identify whether CP child´s age was a predictor of caries risk in each tooth assessed, using the tooth status presence or absence of caries as the dependent variable and age as an independent variable. A logistic regression model was also performed considering sex, age in years and CP classification as potential independent variables that could influence on dental caries experience outcome. The significance level was set at 5%.

Results

Table 1 shows the distribution of the 181 participants according to dentition, sex, age years and CP classification. The sample was homogeneous as regards dentition p=0.6454, sex p=0.6829 and age 0.1932 among the quadriplegia, diplegia, hemiplegia and choreoathetosis groups. The sample consisted of a higher percentage of males 60.8% than females. According to the CP classification, most of the individuals with CP presented quadriplegia 53.1%, followed by diplegia 30.9%, hemiplegia 9.9% and choreoathetosis 6.1%.

Table 1.
Distribution % of the 181 participants according to dentition, sex, age and the classification of CP

Dentition	Classification of CP
	Quadriplegia (n=96)	Diplegia (n=56)	Hemiplegia (n=18)	Choreoathetosis (n=11)	p value
Deciduous	33 (34.4)	12 (21.4)	7 (38.9)	4 (36.4)	0.6454*
Mixed	39 (40.6)	29 (51.8)	8 (44.4)	4 (36.4)
Permanent	24 (25.0)	15 (26.8)	3 (16.7)	3 (27.2)
Sex
Male	59 (61.5)	32 (57.1)	13 (72.2)	6 (54.5)	0.6829*
Female	37 (38.5)	24 (42.9)	5 (27.8)	5 (45.5)
Age (years)
Average ± standard deviation	8.0±4.3	9.3±4.0	7.2±3.9	8.5±3.8	0.1932**

• ^*
  Chi-Square test p<0.05

The overall mean for the dmft and DMFT indices were 1.70±3.30 and 0.70±1.60, respectively. Table 2 shows the distribution of caries experience in primary, mixed and permanent dentition according to the CP classification. In the total sample, 93 participants 51.4% presented no decay. At least one primary or permanent tooth affected by caries was identified in 88 patients 48.6%. The diplegia group presented more caries experience 60.7% than the others. The mean caries experience in primary, mixed and permanent dentitions did not vary significantly according to the CP classification p>0.05.

Table 2.
Distribution of caries experience mean±standard deviation in primary, mixed and permanent dentitions according to the classification of CP

Classification of CP (n)	Caries experience=0 n (%)	Caries experience≥1 n (%)	Primary dentition (n=56)	Mixed dentition (n=80)	Permanent dentition (n=45)
Quadriplegia (96)	53 (55.2)	43 (44.8)	1.5±3.5a	3.4±4.3a	1.3±1.8a
Diplegia (56)	22 (39.3)	34 (60.7)	1.1±2.5a	3.4±3.1a	2.7±2.8a
Hemiplegia (18)	11 (61.1)	7 (38.9)	2.6±5.1a	0.9±1.1a	0.0±0.0a
Choreoathetosis (11)	7 (63.6)	4 (36.4)	7.3±8.4a	1.5±3.0a	2.0±3.5a
p value	-	-	0.3609	0.1698	0.0664

• ^*
  Within columns, significant differences are represented by different superscript lowercase letters Kruskall-Wallis test; p<0.05.

The mean and standard deviation age of the individuals with CP was 3.6±1.6 years for primary dentition, 8.7±2.1 years for mixed dentition and 13.4±2.0 years for permanent dentition. In primary, mixed and permanent dentitions, 73.2%, 37.5% and 48.9% individuals, respectively, were caries free. Although the sample had 60.8% male individuals, there was no statistical difference as regards sex when dental caries was absent p=0.1384 or present p=0.8884 according to the primary, mixed and permanent dentitions.

Figure 1 shows the prevalence of caries in primary and permanent dentitions in individuals with CP. In both maxillary and mandibular arches, primary molars and first permanent molars were the teeth most affected by caries disease. Maxillary anterior teeth were more affected by caries than mandibular anterior teeth, particularly in primary dentition. The permanent teeth most affected by dental caries were the mandibular first molars, followed by the maxillary first molars. The primary teeth most affected were second molars, followed by first molars. The univariate logistic regression, considering CP child´s age as a predictor for caries in primary and first permanent molars, confirmed that CP child´s age was not a predictor for caries in primary molars p>0.05. Considering the first permanent molars, CP child´s age was a predictor for caries in tooth #16 and tooth #36 p<0.05 when they were analyzed separately. However, when the maxillary and mandibular first permanent molars were analyzed together, the results confirmed that CP child´s age was a predictor for dental caries p<0.05.

Figure 1.
Prevalence of caries in primary and permanent dentitions in participants with CP. *Significant association between age and presence of caries by logistic regression p<0.05.

Table 3 shows the logistic regression model considering sex, age and CP classification as predictors on dental caries experience. It could be seen that age years had a significant effect on dental caries experience p<0.05 in children with CP. Sex and CP classification had no significant influence p>0.05.

Table 3.
Logistic regression analysis considering child´s age, sex and CP classification as predictors for the presence of caries

Variable		p value	Odds Ratio	95% Confidence Interval
				Minimum	Maximum
CP classification	Choreoathetosis	0.4190	0.5833	0.1578	2.1563
	Diplegia	0.2263	1.5210	0.7710	3.0003
	Hemiplegia	0.3223	0.5820	0.91992	1.7002
Age (years)		0.0347*	1.0813	1.0056	1.1627
Sex (female)		0.5651	1.1981	0.6472	2.2180

• ^*
  Significant association between by logistic regression p<0.05.

Discussion

Clinically, CP varies in severity and highly diverse levels of functional independence can be observed in individuals with the same medical diagnosis, due to the extent of neurodevelopmental disorder^{1 , 3}. Spastic CP quadriplegia, diplegia and hemiplegia is by far the most common type of movement disorders in cerebral palsy, occurring in 70% to 80% of all cases¹, as observed in this study. This study was conducted in a reference rehabilitation centre for individuals with CP presenting more complex disorders, as observed in the composition of the sample. Most of those subjects presented a quadriplegic and diplegic CP classification, as previously described by Dos Santos and Nogueira⁹ 2005. Moreover, 60.8% of children and adolescents with CP were male, which agrees with the results found by Bax et al.¹⁰ 2006.

It was hypothesized that the increased orofacial muscular tonus and involuntary movements in individuals with CP could have an influence on caries experience, since these characteristics are considered factors leading to difficulty with performing effective oral hygiene¹¹. However, it was observed that the CP classification had no influence on caries experience in these individuals. This could be explained by the implementation of an educational program on oral health directed to the caregivers, who acquired knowledge concerning the main diseases that affected the oral cavity of children with CP and forms of prevention and maintenance of oral health. Moreover, age was a predictor for dental caries experience. In other words, caries experience increases as the individual´s age increases. It could be observed that CP children with diplegia presented a tendency of higher DMFT index in permanent dentition, since these individuals were older than the others and presented more erupted teeth in the oral cavity.

In a previous study⁹, comparisons between CP classifications determined higher values for dmft and DMFT indices among spastic quadriplegic patients. However, the control of caries risk factors is gradually becoming more effective, in a process that involves growing caregiver's knowledge concerning oral hygiene habits, the use of open mouth devices to facilitate toothbrushing, use of fluoride dentifrice and diet control. The fact that the patients were treated in a rehabilitation centre providing constant preventive care might also be a factor in the low dmft and DMFT indices obtained¹².

With regard to the risk of dental caries, the greatest risk is observed in children from low-income families, most often from minority groups and families that include individuals with special care needs¹³, particularly CP^{5 , 8 , 10 , 14}. According to the American Academy of Pediatric Dentistry, they show a moderate risk of caries¹⁵. Dental caries in individuals with CP could be also related to intellectual disability⁴, oromotor dysfunction^{8 , 16}, the regular use of sugary anticonvulsant drugs¹⁷, shorter mastication endurance time¹⁸, biting reflexes⁹ and worse quality of life and continual burden on the caregivers^{5 , 8}, which can further influence oral hygiene⁸. Despite presenting those risk factors, it may be observed that since the individuals with CP are under a continuous preventive follow-up dental care, caries experience can be controlled. Moreover, the mean dmft and DMFT indices of the individuals with CP were lower than the dental caries indices of normoreactive Brazilian children according to the last national survey of dental health¹⁹.

In this study, there was no difference between age and CP classification. It should be stressed that the mean age was expressed in years and not in number of months and might influence the results. For primary dentition, age was similar to that shown in other studies^{5 , 8}. In a clinical study involving patients with CP, Roberto et al.²⁰ 2012 observed that as the primary teeth erupted, the dmft index increased. For mixed dentition, considering both the dmft and the DMFT indices, the caries experience was lower in comparison with previous studies^{5 , 8}. This difference could be explained by the participation of the caregivers in a systematic prevention program developed at the Rehabilitation Centre. For permanent dentition, the caries experience was similar in comparison with the study of de Carvalho et al.²¹ 2011, and in disagreement with Santos et al.⁵ 2010, who reported higher DMFT indices. These differences may be attributed to the location where the study was conducted and the severity of CP in these two populations.

In order to determine the risk of developing oral diseases it is fundamental to identify the types of teeth that are most affected by dental caries in individuals with CP, to determine the types of primary and permanent teeth most affected by caries according to CP child´s age. To the best of the authors' knowledge, this is the first study to assess the types of primary and permanent teeth most affected by caries according to CP child´s age. The difficulty in maintaining the patient's mouth open, due to the muscle tonus¹, hyper-responsivity to oral hygiene stimulus and oral manipulation¹, and non-cooperative behavior⁴ could contribute to food residues on the occlusal surfaces of posterior teeth, as observed on the permanent first molars and the primary first and second molars. Primary second molars and primary and permanent first molars were the most powerful predictors for assignment to the risk group¹³. Motta et al.²² 2012 found that first permanent molars are the teeth most affected by dental caries.

The mandibular anterior teeth were less affected by dental caries than the maxillary anterior teeth, as also occurs in children without any neurological damage. This could be explained by tongue movement and by the fact that a greater salivary film velocity occurs lingual to the mandibular incisors, where biofilm is most readily removed²³. With regard to CP child´s age as a predictor for caries in first permanent molars, analysis showed that these teeth presented greater caries risk with increasing age.

Based on these findings, it seems reasonable to assume that the prevention program requires greater focus on issues specific to this population, including: detailed advice concerning sealant application; fluoride therapy; use of 0.12% chlorhexidine digluconate oral rinse; toothbrushes adapted to facilitate handling by individuals with CP, so they can perform their own oral hygiene wherever possible; the use of dental floss devices; single-tuft toothbrushes for use on occlusal surfaces; and facilitating mouth opening with the use of a dental wooden spatula. All patients with CP should have their dental visits scheduled at shorter time intervals, in order to ensure the best professional care, including constant follow-up of erupting teeth on an individual basis.

In this study, caries experience was assessed by the DMFT and dmft indices proposed by the WHO²⁴ 2013, because this population presents limited cooperation for a more detailed clinical examination of dental caries using other indexes, and incipient enamel lesions i.e., white spot lesions were not evaluated. The examiner was calibrated for the indices and is a dental professional who frequently examines and treats children with CP. The same examiner has previously conducted other studies using these indexes^{5 , 8 - 9 , 16 , 25}. Moreover, there was no control group of patients without alteration. Another research has compared children with CP with normorreactive subjects²⁶, but the mentioned study assessed a small number of patients compared with this investigation.

Another limitation of the present investigation relates to the different number of subjects in each CP classification, which may have influenced the results. Despite the quantitative differences between the assessed groups, they correspond to the percentages found in the population, with a higher prevalence of quadriplegia.

In conclusion, the CP classification had no influence on caries experience, and the teeth most affected by dental caries were the primary molars and first permanent molars.

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Publication Dates

• Publication in this collection
  Jan-Mar 2015

History

• Received
  21 Jan 2015
• Accepted
  17 Mar 2015