Three-dimensional longitudinal changes of maxilla and mandible morphology during the predental period.

AIM: The purpose of this study was to longitudinally analyse the morphology of maxilla and mandible over time in infants using a three-dimensional (3D) surface scanner. MATERIALS AND METHODS: Seventeen Japanese full-term infants participated in the study. Dental plaster models were fabricated every 3 months from 1 month of age to 12 months. The plaster models were scanned using the 3D surface scanner to create 3D models. The arch width, arch length, arch angle, palatal depth and palatal area of the 3D models were analysed. RESULTS: The arch width and length of maxilla and mandible increased as the arch angle decreased. The arch width and length of the maxilla were greater than those of the mandible. The total alveolar ridge morphology increased in size in the occlusal view, with marked growth in the sagittal direction. The palatal depth remained virtually unchanged although the palatal area increased as a result of buccal growth of the alveolar ridge. CONCLUSIONS: The morphological growth pattern of the maxilla and mandible in infants can be evaluated quantitatively using 3D analysis. Knowledge about the healthy development of children and their orofacial growth patterns during the predental period can be applied as an index for diagnostic criteria.

Treatment of ectopic eruption of permanent mandibular first molars with innovative dental appliances.

AIM: Ectopic eruption (EE) of a first permanent molar occurs during mixed dentition. However, treatment of first permanent mandibular molar EE has been seldom reported. CASE REPORT: The cases of an 8-year-old girl and a 7-year-old boy are described, whose EE first permanent mandibular molars were correctly positioned after treatment with a dental appliance comprising a lingual arch, sectional arch, crimpable hook, and power chain or a simple molar controller, respectively. Both dental appliances are technically easy to construct, require short chair time, induce little discomfort on the patient, and ensure high-level treatment efficiency.

Comparative analyses of paediatric dental measurements using plaster and three-dimensional digital models.

AIM: Recent advances in three-dimensional imaging have led to an increased interest in the application of computer-models in paediatric dentistry. However, in evidence-based paediatric dentistry the accuracy of new methods must be validated before they are introduced to clinical practice. We aimed to compare the accuracy of measurements of digital models obtained using a non-contact 3D measuring system, with direct measurements made on plaster models (gold standard) from children. MATERIALS AND METHODS: Twelve pairs of plaster models were obtained from children with deciduous dentition; tooth size, arch width, and arch length were examined. The same parts on each cast were measured twice with at least a 2-week interval between measurements with each method by four examiners. Linear mixed-effects model analyses were performed for comparison of values from the 2 different measurement methods. RESULTS: The average difference between the 2 methods in measured values, derived from the final model, was <0.2 mm. Random effect of examiners was always the smallest component of variance, and frequently negligible. STATISTICS: Intraclass correlation coefficients were typically >90%. CONCLUSION: These results suggest that primary dentition analysis of digital models has a high accuracy level, comparable to that of direct measurement of plaster models by digital calipers.

Application of three-dimensional digital models for the morphometric analysis of predentition plasters: accuracy and precision.

AIM: This study aimed to test the accuracy and precision of measurements of three-dimensional (3D) digital models from the pre-dentition period using a noncontact 3D measurement system (3D scanner) versus the gold standard method of direct measurements using a digital caliper on plaster models. MATERIALS AND METHODS: Ten pairs of plaster models were obtained from children during the predentition period. Linear measurements were performed using both methods. Three operators were trained in the use of both methods for this study. Measurements were performed with a minimum 2-week interval between measurements in a randomly chosen order. RESULTS: The mean difference between the measured values using the two methods was <0.2 mm for each measurement. There was no linearity in the measurements using pre-dentition digital models. An ANOVA Gage R&R analysis revealed that there was no significant operator difference (P < 0.307). The rate of variation of the 3D scanner over the total variation was 2.8%. The ICC was 0.982 (P< 0.001), suggesting excellent interoperator agreement. CONCLUSION: The results suggest that measurements of digital 3D pre-dentition models are highly accurate and precise, and also comparable to measurements using the gold standard method.

Establishment of indicator for screening of child abuse and neglect in primary school-age children.

AIM: In Japan, elementary schools are committed to early discovery of child abuse and neglect. Under Japanese law, dentists are required to be involved in child welfare and early detection of child abuse. However, the extent to which dental practitioners cooperate for prevention of child abuse with schools remains limited to date. Therefore, we undertook a community-based project that aimed to develop screening indicators to identify potentially abused children based on their oral health condition and behavioural characteristics in education settings. We have already reported on the relationship between oral health condition and child abuse. The present study established an indicator that can facilitate identification and prevention of child abuse/neglect. METHODS: Study design: Cross-sectional study. Questionnaires were given to teachers at an elementary school to ascertain behavioural characteristics observed in children who experienced abuse. CONCLUSION: We developed a check sheet for proper assessment, which requires as little effort as possible, and an index for screening children in need based on teaching staff's observation of students' daily behaviour in school settings. Highly selected items are advantageous as they lead to a decrease in non-response or responses, which can help in improving the accuracy of the response to each question.

Relationship between gingival health and dental caries in children aged 7-12 years.

The purpose of this study was to investigate the relationship between gingival health and dental caries in elementary school children in Japan. The subjects were 474 children aged 7 to 12 years who attended dental check-ups at an elementary school. The Oral Rating Index for Children, which consists of five categories (+2, +1, 0, -1, -2), was used to rate the findings of the gingival health examination. The dental examination was performed using the WHO caries diagnostic criteria for DMFT. Children were divided into three groups: a healthier group (H-group) made up of those scoring +2 (excellent) or +1 (good), an equivocal group (E-group) made up of those scoring 0, and a gingival less-healthy group (L-group) made up of those scoring -2 (very poor) or -1 (poor). Overall percentages for the H-group, E-group and L-group were 48.3%, 21.5% and 30.2%, respectively. The number in the L-group increased with increasing age. The mean scores of the DT and DMFT in the H-group were significantly lower than those in the L-group (p < 0.01 and p < 0.05, respectively). The results suggest that oral hygiene instruction should be given to children in order to motivate self-care, not only to avoid dental caries but also to prevent gingivitis.

Influence of parents' oral health behaviour on oral health status of their school children: an exploratory study employing a causal modelling technique.

OBJECTIVES: The aim of this study was to examine the simultaneous interrelationships between parents' oral health behaviour and the oral health status of their school children. SAMPLE AND METHODS: Subjects comprised 296 pairs of parents (mother or father) and their children at an elementary school in Hiroshima. The child's dental examination was performed using the World Health Organization (WHO) caries diagnostic criteria for decayed teeth (DT) and filled teeth (FT). The Oral Rating Index for Children (ORI-C) was used for the child's gingival health examination. Hiroshima University Dental Behavioural Inventory (HU-DBI) was used for the assessment of the parents' oral health behaviour. A parent-child behavioural model was tested by the linear structural relations (LISREL) programme. RESULTS: There was a significant correlation between DT and ORI-C (r = - 0.168; P < 0.01). Correlation was found between ORI-C and oral health behaviour in children (OHB-C) (r = 0.182; P < 0.01). OHB-C was significantly associated with the HU-DBI (r = 0.251; P < 0.001). The hypothesized model after some revisions was found to be consistent with the data (chi(2) = 1.3, d.f. = 6, P = 0.97; Goodness of Fit Index = 0.999). Parents' oral health behaviour affected their children's oral health behaviour (P < 0.001). Children's oral health behaviour affected their DT through its effect on gingival health level. Parents' oral health behaviour also had a significant direct effect on their children's DT (P < 0.05). Children's grade affected both DT and their oral health behaviour. CONCLUSIONS: Parents' oral health behaviour could influence their children's gingival health and dental caries directly and/or indirectly through its effect on children's oral health behaviour.