3D follow-up study of facial asymmetry after developmental dysplasia of the hip.

OBJECTIVES: To evaluate the change in facial asymmetry among subjects treated for developmental dysplasia of the hip (DDH) from childhood to adolescence. SETTING AND SAMPLE POPULATION: A total of 39 adolescents (26 females and 13 males), born and treated for DDH during 1997-2001, participated in the first examination in 2007 (T1; at the age of 8.2) and in the follow-up in 2016 (T2; at the age of 16.6). MATERIAL AND METHODS: In this longitudinal study, three-dimensional (3D) images were taken using a 3DMD face system based on a stereophotogrammetric method. Facial asymmetry was determined as the average distance (mm) calculated between the original and superimposed mirrored face and the symmetry percentage (%) calculated as the face area where the distance between the original face and the mirrored surface does not exceed 0.5 mm. RESULTS: Results showed increased asymmetry from T1 to T2. The average distance increased for whole face (from 0.51 mm to 0.59 mm, P = .001), upper face (from 0.41 mm to 0.49 mm, P = .005), mid-face (from 0.48 mm to 0.57, P = .002) and lower face (from 0.74 mm to 0.85 mm, P = .147). Facial symmetry percentage decreased for whole face from 61.23% to 55.38% (P = .011), for upper face from 69.27% to 62.24% (P = .005) and for mid-face from 62.29% to 55.63% (P = .007) and for lower face from 43.37% to 42.19% (P = .66). CONCLUSION: Facial asymmetry increases from childhood to adulthood in subjects treated for DDH. Orthodontic treatment does not eliminate this asymmetric facial growth.

Primary tooth size asymmetry in twins and singletons.

OBJECTIVES: To explore asymmetry values of antimeric deciduous tooth crown dimensions in three types of twins: monozygotic (MZ), dizygotic same-sex (DZ) and opposite-sex (OS) vs. single-born controls. SETTING AND SAMPLE POPULATION: Mesiodistal and labio-lingual crown dimensions of second deciduous molars and mesiodistal canine and first molar crown dimensions of 2159 children at 6-12 years of age were evaluated, originating from the US cross-sectional Collaborative Perinatal Study from the 1970s, including altogether MZ (n = 28), DZ same-sex (n = 33) and OS (n = 39) pairs. Single born (n = 1959) were used as controls. MATERIAL AND METHODS: Dental casts were measured for comparison of variance relationships calculated from antimeric teeth, exhibiting fluctuating (FA), and directional (DA) asymmetry using anova. RESULTS: Significant differences appeared in MZ and OS girls in DA of deciduous canines, which gain size in the first and second trimester, and deciduous second molars, which finally stop crown growth during the early post-natal period. Significantly, increased FA values appeared for lower deciduous canines and second molars, indicating greatest environmental stress in OS girls, MZ girls and DZ boys. Twin girls had more fluctuating and directional crown asymmetry than twin boys, but in some dimensions, the twins were more symmetric than controls. CONCLUSIONS: Transmembrane hormonal influence between opposite-sex twins, and late gestational stress factors, caused by placental malfunction and/or monochorionicity, may be involved in asymmetric growth of antimers, during critical periods of crown size gain.

Can the results of the OSCE predict the results of clinical assessment in dental education?

INTRODUCTION: The aims of this study were to evaluate the correlation between the results of the objective structured clinical examination (OSCE) and clinical assessment and to test the reliability of OSCE test stations. MATERIAL AND METHODS: All 4th year undergraduate dental students (n = 47, 100%) attended the OSCE in April 2010. The students were divided into two groups (morning group, group 1; afternoon group, group 2). Groups 1 and 2 were also divided into two subgroups that attended the stations in two concurrent sessions (A and B). The OSCE included 12 10-min test stations. Clinical assessment was based on long-term observation during the semesters. The disciplines assessed were cross-infection control, endodontics, paediatric dentistry, periodontology, prosthodontics and restorative dentistry. RESULTS: Statistical analysis using Cronbach's alpha indicated good reliability of the OSCE. The correlation between the results of the OSCE and clinical assessment in the 4th year was statistically significant in cross-infection control (ρ = 0.340, P = 0.022), endodontics (ρ = 0.298, P = 0.047), prosthodontics (ρ = 0.296, P = 0.048) and restorative dentistry (ρ = 0.376, P = 0.011). Clinical assessment in the 5th year correlated with the OSCE results statistically significant in restorative dentistry (ρ = 0.522, P = 0.001). CONCLUSION: Both the OSCE and constant longitudinal assessment are needed in clinical assessment, as they both play an important role in the overall assessment.

Dental arch relationships assessed by GOSLON Yardstick in children with clefts in Northern Finland.

AIM: Our purpose was to evaluate the dental arch relationships using the GOSLON Yardstick in children with cleft lip and or cleft palate in Northern Finland. MATERIALS AND METHODS: The subjects consisted of 62 Finnish patients (36 girls and 26 boys) with clefts born between 1995-2005 in the Northern Ostrobothnia Hospital District of Finland. There were 36 patients with cleft palate, 9 with unilateral cleft lip and palate, 6 with cleft in soft palate, 5 with bilateral cleft lip and palate, 2 with cleft lip and 4 with submucous clefts. The study casts were obtained at the mean age of 6.3 years (5.8-7.8 years) and the cases were selected randomly. The dental arch relationships were assessed by the GOSLON Yardstick method by one calibrated researcher. RESULTS: After the assessment, 77.1% of cases were allocated to categories 1 and 2 (excellent and good), 10.4% category 3 (fair), and 12.5% categories 4 and 5 (poor and very poor). Patients with cleft palate had good prognosis in 84.6% of the cases. Of the patients with soft palate clefts and unilateral cleft lip and palate, 66.7% were allocated to categories 1 and 2. Bilateral cleft lip and palate patients had the poorest prognosis. Patients with submucous cleft and cleft lip had all good prognosis. CONCLUSION: The GOSLON Yardstick is a useful method for assessing dental arch relationships and treatment prognosis not only in cleft lip and palate patients, but also in cleft palate patients.

Experiences in adding multiple-choice questions to an objective structural clinical examination (OSCE) in undergraduate dental education.

In the University of Oulu, the competencies of fourth-year dental students have traditionally been assessed with a written examination before they go to work for the first time as dentists outside the Institute of Dentistry. In 2009, the objective structural clinical examination (OSCE) modified with multiple-choice questions was introduced as a tool for assessing clinical competencies. The aim of the study was to evaluate the validity of the modified OSCE (m-OSCE) by measuring the attitude of examiners (teachers) and dental students towards the m-OSCE and to evaluate whether the OSCE is preferred to the written examination in the assessment of knowledge and clinical skills. Additionally, the aim was to evaluate the reliability of the multiple-choice examination. Altogether 30 students (86%) and 11/12 examiners (92%) responded to the questionnaire. Most of the students considered the multiple-choice questions easy, but complained about the complex formulation of the questions. The test stations were easy for 87% of the students, but the time allocated was too short. Most of the students (73%) and examiners (91%) preferred the m-OSCE to the written examination. All students and examiners found the immediate assessment of the tasks good. Based on the evaluations of m-OSCE, it could be concluded that both students and examiners preferred the m-OSCE to the pure written examination in assessment, which indicate that m-OSCE had good face validity. Combining multiple methods in assessment of knowledge and clinical skills whilst simultaneously taking into account the feasibility and available resources provides more valid results.

An exploration of adolescent facial shape changes with age via multilevel partial least squares regression.

BACKGROUND AND OBJECTIVES: Multilevel statistical models represent the existence of hierarchies or clustering within populations of subjects (or shapes in this work). This is a distinct advantage over single-level methods that do not. Multilevel partial-least squares regression (mPLSR) is used here to study facial shape changes with age during adolescence in Welsh and Finnish samples comprising males and females. METHODS: 3D facial images were obtained for Welsh and Finnish male and female subjects at multiple ages from 12 to 17 years old. 1000 3D points were defined regularly for each shape by using "meshmonk" software. A three-level model was used here, including level 1 (sex/ethnicity); level 2, all "subject" variations excluding sex, ethnicity, and age; and level 3, age. The mathematical formalism of mPLSR is given in an Appendix. RESULTS: Differences in facial shape between the ages of 12 and 17 predicted by mPLSR agree well with previous results of multilevel principal components analysis (mPCA); buccal fat is reduced with increasing age and features such as the nose, brow, and chin become larger and more distinct. Differences due to ethnicity and sex are also observed. Plausible simulated faces are predicted from the model for different ages, sexes and ethnicities. Our models provide good representations of the shape data by consideration of appropriate measures of model fit (RMSE and R2). CONCLUSIONS: Repeat measures in our dataset for the same subject at different ages can only be modelled indirectly at the lowest level of the model at discrete ages via mPCA. By contrast, mPLSR models age explicitly as a continuous covariate, which is a strong advantage of mPLSR over mPCA. These investigations demonstrate that multivariate multilevel methods such as mPLSR can be used to describe such age-related changes for dense 3D point data. mPLSR might be of much use in future for the prediction of facial shapes for missing persons at specific ages or for simulating shapes for syndromes that affect facial shape in new subject populations.

Facial morphology of Finnish children with and without developmental hip dysplasia using 3D facial templates.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a condition that affects the femoral head and the acetabulum and leads to hip subluxation and dislocation. Infants with DDH are usually treated using splints that immobilize their hip joint and are forced on their back for long periods of time. The link between positioning and facial asymmetries is poorly understood. OBJECTIVE: To compare the facial morphologies of children with DDH to a group of healthy controls. SUBJECTS AND METHODS: Fifty-six Finnish patients born with DDH were matched on the basis of gender and age to a control group. Three-dimensional surface images were captured using the 3dMDface system. Using RF6 PP2 software, anthropometric landmarks were plotted and used to calculate asymmetry based on 3D co-ordinates in a reference framework. RESULTS: There was statistically significant difference between all paired facial shells. Relative to the control group, DDH boys and girls presented a chin-point deviation to the right, a more prominent left orbital ridge, a more protrusive nose and upper lip. The gender-specific subgroups show a similarity of 66.54 and 65.22% in girls and boys, respectively. CONCLUSIONS: Patients with DDH present a facial asymmetry when compared to healthy controls. Gender characteristics are marked whether subjects are affected with DDH or not. Three-dimensional surface imaging is a powerful diagnostic and research tool.

Multilevel principal components analysis of three-dimensional facial growth in adolescents.

BACKGROUND AND OBJECTIVES: The study of age-related facial shape changes across different populations and sexes requires new multivariate tools to disentangle different sources of variations present in 3D facial images. Here we wish to use a multivariate technique called multilevel principal components analysis (mPCA) to study three-dimensional facial growth in adolescents. METHODS: These facial shapes were captured for Welsh and Finnish subjects (both male and female) at multiple ages from 12 to 17 years old (i.e., repeated-measures data). 1000 "dense" 3D points were defined regularly for each shape by using a deformable template via "meshmonk" software. A three-level model was used here, namely: level 1 (sex/ethnicity); level 2, all "subject" variations excluding sex, ethnicity, and age; and level 3, age. The technicalities underpinning the mPCA method are presented in Appendices. RESULTS: Eigenvalues via mPCA predicted that: level 1 (ethnicity/sex) contained 7.9% of variation; level 2 contained 71.5%; and level 3 (age) contained 20.6%. The results for the eigenvalues via mPCA followed a similar pattern to those results of single-level PCA. Results for modes of variation made sense, where effects due to ethnicity, sex, and age were reflected in modes at appropriate levels of the model. Standardised scores at level 1 via mPCA showed much stronger differentiation between sex and ethnicity groups than results of single-level PCA. Results for standardised scores from both single-level PCA and mPCA at level 3 indicated that females had different average "trajectories" with respect to these scores than males, which suggests that facial shape matures in different ways for males and females. No strong evidence of differences in growth patterns between Finnish and Welsh subjects was observed. CONCLUSIONS: mPCA results agree with existing research relating to the general process of facial changes in adolescents with respect to age quoted in the literature. They support previous evidence that suggests that males demonstrate larger changes and for a longer period of time compared to females, especially in the lower third of the face. These calculations are therefore an excellent initial test that multivariate multilevel methods such as mPCA can be used to describe such age-related changes for "dense" 3D point data.

Open bite in prematurely born children.

PURPOSE: The aims of this study were to: examine the expression of open bite in prematurely born children and discuss the etiological factors that may lead to bite it. METHODS: The subjects were 328 prematurely born (<37 gestational weeks) Caucasoid and African American children and 1,804 full-term control children, who participated in the cross-sectional study of the Collaborative Perinatal Project in the 1960s and 1970s. Dental documents, including casts and photographs, were taken once at the age of 6-12 years in the mixed dentition. The occlusion was recorded by examining and measuring the hard stone casts. Vertical open bite was recorded only for full erupted teeth. The statistical method used was chi-square analysis. RESULTS: Significant differences in the incidence of anterior open bite (from left to right canine) was found between the preterm and control groups and between gender and ethnic groups. The prevalence of anterior open bite was nearly 9% in the preterm group and almost 7% in the control group. African Americans (9%) had a significantly greater incidence of open bite than Caucasians (3%; P<.0001). Generally, girls had a greater incidence of open bite than boys (8% vs 6%; P<.11). When the study groups were divided by prematurity, gender, and ethnic group, the prevalence of open bite was increased--especially in preterm African American boys compared to controls (11% vs 8%). CONCLUSIONS: The results show differences in the development of anterior open bite between ethnic and gender groups. Premature birth may also influence dental occlusal development. Of importance are the patient's: general health condition; respiratory infections; inadequate nasal- and mouth-breathing; oral habits; and other medical problems. Preterm children may be relatively more predisposed to etiological factors for the development of anterior open bite.