In this epidemiological study, conducted with the collaboration of the local health authority (ASL 3, 1st
District, School Medicine Services), 605 children (mean age 8.5
2.3 years; 45% males; 55% females) attending the 3rd
years of seven Genoa primary schools were examined.
Before any clinical research was performed, the parents of the children attending the selected classes were asked to provide informed consent and to fill in an anamnestic survey (i.e., birth, breast and/or formula feeding habits, dummy- or thumb-sucking, headaches, dental and general trauma, pain in the muscles of the head and neck and nocturnal bruxism). The questionnaire pertaining to each child was then used at subsequent clinical examinations to notify the medical specialists of any related disorders, thereby assisting them in the formation of an accurate clinical picture. During this screening, each child underwent the following examinations: 1) dental/occlusal; 2) orthoptic; and 3) osteopathic-postural. These investigations were performed at the school by two dentists, one orthoptist and one osteopathist, under the expert supervision of a clinician specialized in School Medicine (from the ASL 3, 1st
District). The examination protocol adopted was based on previous studies [16
Three clinical evaluation forms that were previously designed were used to record the dental, orthoptic and postural data, and a medical record of each child was compiled.
Postural assessment involved frontal and lateral inspection, investigation during trunk flexion and ambulation, and note of any asymmetry in the lower limbs was taken (Figure ). The collected dental information contained details of the molar and canine relationships, dental and facial midline, overbite, transversal relationships (cross-bite presence/absence), bad habits, hygiene and ongoing orthodontic treatment (Figure ). The recorded orthoptic data included those pertaining to a cover test, convergence, ocular dominance and the Brock string test (Figures , , ).
Postural assessment involved frontal and lateral inspection, investigation during trunk flexion and ambulation, and note of any asymmetry in the lower limbs or shoulders was taken.
Figure 2 Occlusal alterations; (a) overbite alteration: deepbite; (b) overbite alteration: openbite; (c) molar and canine correct classification: class I relationship; (d) median line deviation; (e) alteration of the transversal relationship: crossbite; (f) bad (more ...)
Cover test for eyes; (a) ortotrophia; (b) esotrophia; (c) exotrophia; (d) hipertrophia.
The following eye tests were carried out primarily to determine postural information:
Cover/uncover test (CT; Figure ): The test was performed by covering and uncovering each eye in turn (e.g., with a hand or occluder) while the patient fixated on a small object. The purpose of the test was to determine any re-fixation movement in the uncovered eye. In this way, each eye was considered as a single entity and any axial defects (heterophoria) were detected by the presence of re-fixation movements in the uncovered eye (dissociation of the right and left eyes). An experienced ophthalmologist was then able to quantify the degree of phoria by passing a test card featuring increasing prism diopter values before the eyes until the re-fixation movement disappeared.
Convergence test (CT; Figure ): The test was performed up to the base of the nose to determine the degree of tonic (dynamic), fusional and accommodative convergence.
There are two types of convergence:
Dynamic convergence (smooth pursuit system), which is considered pathological if the saccadic movements of one eye are slower than the other, the convergence movement of one or both eyes fails to complete, or the eye or eyes wander outwards when attempting to converge. Postural imbalance resulting from this condition will be greater if the defect is more pronounced in one eye.
Reflexive convergence (saccadic system), which seems to involve the saccadic rather than pursuit system, and is considered pathological if an eye fails to converge, stops in transit or wanders outwards when attempting to perform convergence. If the two eyes contradict each other, the convergence defect is considered to be present in both eyes. If the hypoconvergent eye protrudes and points downwards during reflexive convergence, a phoria or trophia is likely to be present.
Ocular dominance test (Figure ): A card with a hole of diameter 2 cm is placed a distance of 10–15 cm from the patient’s eyes. The patient is then asked to stare through the hole at a distant object and the eye that automatically complies is the dominant eye. Confirmation of ocular dominance can be achieved by covering each eye in turn and repeating the test. Without moving the pierced card, the dominant eye will be the only one able to see the object in the center of the hole.
Parents were present and fully informed about the clinical findings. All patients approved the inclusion of their data in this study. The research reported in the paper was undertaken in compliance with the Helsinki Declaration. Ethical approval was granted by the Ethics Committee of the S. Martino Hospital- University of Genoa-National Institute for Cancer Research (P.R 21/12). Written consent was obtained after orientation to the study.
All data were analyzed in the form of percentages of subjects with a particular occlusal or postural or ocular situation. The percentages of subjects with postural or ocular diseases were compared among subjects with a normal, deep or open bite.
A chi-square test was used to evaluate the null hypothesis stating that the frequency distributions of gait posture, leg dysmetry or ocular diseases observed in our sample were consistent with a particular theoretical distribution. The null hypothesis was that the considered diseases were mutually exclusive and had the same probability for each type of teeth bite (open, normal or deep bite) because all the disease outcomes were equally likely to occur. The percentages were compared with a chi-square test. The p level was set at 0.05.
The software SPSS 9.0 was employed to evaluate statistical tests.