Our aims in this study were to compare the biopsychosocial aspects of patients with cerebral palsy and subjects in a control group, establish the severity of malocclusion, and identify determinant factors.
The group with cerebral palsy included 60 patients diagnosed with the spastic form of the disease. The control group included 60 randomly selected healthy subjects with various malocclusions. Data were collected through questionnaires, medical charts, and clinical evaluations. The criteria of the dental aesthetic index were used for the diagnosis of malocclusion. Comparisons between groups and between the independent variables and dependent variable (severity of malocclusion) were performed by using the chi-square test ( P ≤0.05) and multivariate logistic regression (forward stepwise procedure).
Significant differences between the groups were found for these variables: tooth loss, overjet, anterior open bite, facial type, breathing pattern, drooling, difficulty in swallowing, and lip incompetence.
The main risk factors associated with the severity of malocclusion were cerebral palsy, mouth breathing, lip incompetence, and long face.
Cerebral palsy is an umbrella term for a group of conditions characterized essentially by motor dysfunctions that might be associated with sensory or cognitive impairment stemming from a nonprogressive brain lesion during development. Its prevalence is about 2 of every 1000 live births. Impairments range from mild, with little difficulty, to severe, in which the child completely depends on others for the activities of daily living.
The classification of cerebral palsy depends on the predominant motor alteration. Spastic cerebral palsy, the most common type, is characterized by a lesion in the cerebral cortex, with reduction in strength and increase in muscle tonus. Athetoid cerebral palsy is characterized by involuntary movements. Ataxic cerebral palsy is characterized by difficulties in motor coordination (trembling when performing a movement). The mixed type involves characteristics of 2 types of cerebral palsy at the same time (eg, spastic and athetoid).
In relation to oral health, persons with cerebral palsy are more prone to problems. They have greater prevalence of enamel hypoplasia, high frequencies of carbohydrate and pasty food intake, self-hygiene challenges, greater difficulty in chewing and swallowing, greater use of medication, and greater prevalences of periodontal disease and malocclusion.
The main characteristics associated with the prevalence of malocclusion among patients with cerebral palsy are musculoskeletal abnormalities, altered cranial-base relationships, premature tooth eruptions, and lip incompetence. However, the severity of malocclusion varies, depending on the degree of impairment. A critical evaluation of the literature showed that studies failed to identify determinant factors in considering the severity of malocclusion in those with cerebral palsy. The methods and statistical analyses used were limited to providing descriptive data and comparisons between heterogeneous groups but failed to consider diverse biopsychosocial variables. This problem is all the more critical because children with cerebral palsy receive little dental care, mainly because the difficulty in handling them. Thus, a better understanding of the factors related to the prevalence and severity of malocclusion in these patients is essential to planning actions and public policies for the promotion of oral health.
Our aims in this study were to compare the biopsychosocial aspects of subjects with cerebral palsy with those of persons in a control group, establish the severity of malocclusion, and identify determinant factors.
Material and methods
The sample included 120 subjects (60 with cerebral palsy, 28 boys and 32 girls; and 60 with no physical or mental impairment, 19 boys and 41 girls) with an average age of 12.6 years. Those with cerebral palsy had the spastic form, with little or no control over their arms and legs, no ability to execute activities without assistance, and mental impairment. The control group was selected randomly from healthy people with various malocclusions who awaited orthodontic treatment at University of Itaúna.
The inclusion criteria for participation in the group with cerebral palsy were a confirmed diagnosis of spastic cerebral palsy and no previous orthodontic intervention. Parents or guardians of the participants signed informed consent forms. The study was approved by the ethics committee of the University of Três Corações in Brazil.
The data were collected through questionnaires, medical charts, and clinical examinations of the participants. The criteria of the dental aesthetic index (DAI) were used for the diagnosis of malocclusion. The DAI provides 4 outcome possibilities: mild malocclusion or absence of abnormality, the treatment of which is unnecessary (DAI <25); defined malocclusion, the treatment of which is elective (DAI = 26-30); severe malocclusion, the treatment of which is highly desirable (DAI = 31-35); and very severe or debilitating malocclusion, the treatment of which is fundamental (DAI >36). Because all the participants in this study had malocclusions, this variable was dichotomized into moderate malocclusion (DAI ≤30) and severe malocclusion (DAI >30). Crossbite and facial type were also determined. The malocclusions were clinically classified as Angle Class I, Class II, or Class III.
Lip incompetence was assessed with the method described by Ballard: mandible in physiological resting position in juxtaposition (sealed), with no contraction of the orbicular muscles of the mouth or mentalis. Lip incompetence and breathing type (nasal or mouth) were determined during the clinical examination and the interview with the parent or guardian when the child thought he or she was not being observed. Drooling was determined based on the method described by Thomas-Stonell and Greenberg : 1, no drool; 2, medium: small amount, only on the lips; 3, moderate: small amount on lips and chin; 4, severe: drool on clothes; and 5, profuse: wet clothes, hands, and objects. Cerebral palsy was diagnosed based on the medical chart.
Comparisons between groups and between the independent and dependent (severity of malocclusion) variables were carried out by using the chi-square test ( P ≤0.05). Variables with a P value ≤0.20 were included in the multivariate logistic regression model (forward stepwise procedure).
Concerning the occlusal problems, the patients with cerebral palsy had significant differences compared with the control group for tooth loss, overjet, and anterior open bite. Differences between the groups were also found for facial type and Angle classification ( Table I ). Table II shows severe malocclusions in 68% of the patients with cerebral palsy, in 80.6% of the mouth breathers, in 84.2% of those with severe drooling, in 87.3% of those with difficulty swallowing, in 74.4% of those with lip incompetence, and in 71.1% of those with long face. After adjusting the model, the logistic regression analysis showed that those with cerebral palsy (3.21 [1.14-9.01]), mouth breathers (4.82 [1.57-14.77]), those with lip incompetence (2.86 [1.03-7.96]), and those with long face (5.48 [1.86-13.26]) had a greater chance of having a severe malocclusion ( Table III ).
|Control, n (%)||Cerebral palsy, n (%)||P|
|None||59 (55.1)||48 (44.9)||0.001|
|At least 1||1 (7.7)||12 (92.3)|
|None||31 (43.1)||41 (56.9)||0.062|
|1 or 2 segments||29 (60.4)||19 (39.6)|
|None||34 (54.0)||29 (46.0)||0.361|
|1 or 2 segments||26 (45.6)||31 (54.4)|
|<2||47 (54.7)||39 (45.3)||0.105|
|≥2||13 (38.2)||21 (61.8)|
|Maxillary irregularity (mm)|
|<2||48 (47.5)||53 (52.5)||0.211|
|≥2||12 (63.2)||7 (36.8)|
|Mandibular irregularity (mm)|
|<2||50 (47.6)||55 (52.4)||0.168|
|≥2||10 (66.7)||5 (33.3)|
|<4||46 (63.9)||26 (36.1)||<0.001|
|≥4||14 (29.2)||34 (70.8)|
|No||59 (50.4)||58 (49.6)||1.000|
|Yes||1 (33.3)||2 (66.7)|
|Anterior open bite (mm)|
|<2||57 (62.6)||34 (37.4)||<0.001|
|≥2||3 (10.3)||26 (89.7)|
|Absent||52 (51.5)||49 (48.5)||0.453|
|Present||8 (42.1)||11 (57.9)|
|Average||45 (61.6)||28 (38.4)||0.006|
|Short face||1 (50.0)||1 (50.0)|
|Long face||14 (31.1)||31 (68.9)|
|Class I||31 (56.4)||24 (43.6)||0.036|
|Class II||25 (53.2)||22 (46.8)|
|Class III||4 (22.2)||14 (77.8)|
|Severity of malocclusion (DAI)|
|Control||47 (78.3)||13 (21.7)||<0.001|
|Cerebral palsy||19 (31.7)||41 (68.3)|
|Female||45 (61.6)||28 (38.4)||0.068|
|Male||21 (44.7)||26 (55.3)|
|<10||32 (57.1)||24 (42.9)||0.659|
|≥10||34 (53.1)||30 (46.9)|
|Birth weight (g)|
|>2500||29 (54.7)||24 (45.3)||0.709|
|≤2500||11 (50.0)||11 (50.0)|
|No||58 (58.6)||41 (41.4)||0.081|
|Yes||7 (36.8)||12 (63.2)|
|Schooling of caregiver (y)|
|>8||36 (62.1)||22 (37.9)||0.132|
|≤8||30 (48.4)||32 (51.6)|
|Common old, last time (mo)|
|≥1||34 (50.7)||33 (49.3)||0.948|
|<1||13 (50.0)||13 (50.0)|
|Nasal||59 (70.2)||25 (29.8)||<0.001|
|Mouth||7 (19.4)||29 (80.6)|
|No||55 (71.4)||22 (28.6)||<0.001|
|Yes||11 (25.6)||32 (74.4)|
|Absent||60 (66.7)||30 (33.3)||<0.001|
|Moderate||3 (27.3)||8 (72.7)|
|Severe||3 (15.8)||16 (84.2)|
|No||64 (61.5)||40 (38.5)||<0.001|
|Yes||2 (12.5)||14 (87.5)|
|Deciduous||5 (38.5)||8 (61.5)||0.191|
|Mixed||42 (61.8)||26 (38.2)|
|Permanent||19 (48.7)||20 (51.3)|
|Average||53 (72.6)||20 (27.4)||<0.001|
|Short face||0 (0.0)||2 (100.0)|
|Long face||13 (28.9)||32 (71.1)|