Papers by Tuomo Heikkinen
Journal of dentistry for children, 2009
PURPOSE The purpose of this study was to explore the sidedness of primary tooth horizontal wear f... more PURPOSE The purpose of this study was to explore the sidedness of primary tooth horizontal wear facets between the left and right sides of the dentition among 2 types of functionally lateralized (hand, foot, eye) children--those who were true right-sided (TRS), and partially or totally nonright-sided (NRS) at 4 years of age. METHODS Study subjects were 855 children with signs of wear in deciduous teeth on the dental casts (N=1,720) of the GOS (Genetic Odontometric Study of the Collaborative Perinatal) project, carried out in the 1960s in the United States by the National Institute of Neurological Disorders and Stroke (NINDS) in a cross-sectional manner at a mean age of 8(1/2) years (40% Caucasian and 60% African-American children). The statistical method used was chi-square analysis. RESULTS Tooth wear was identified from dental casts in approximately 50% of cases. Wear was symmetric (equal on the right and left) in 49% of these dentitions, while asymmetric wear was found in 50%. Le...
Acta Odontologica Scandinavica
Objective: To resolve how the preferred chewing side (PCS) affects facial asymmetry in twins, whe... more Objective: To resolve how the preferred chewing side (PCS) affects facial asymmetry in twins, whether there are differences between monozygotic (MZ) and dizygotic (DZ) twins, and whether the twins with PCS have more asymmetric faces compared to symmetrically chewing twins. Material and methods: The study included 106 Lithuanian twin pairs of the same sex, 59 MZ and 47 DZ pairs. The data were analysed from facial 3D images and manually added landmarks. 3D images were analysed by Rapidform2006 software and statistical analyses were done by using the R software environment version 4.1.0. Results: The contralateral effect of PCS and larger chin side was dominant among right and non-right side chewing twins. Being female increased the whole face symmetry. Conclusion: The volume of the chin becomes larger on the side opposite to the twins' habitual chewing side. As the results are quite similar in both twin types, functional factors are more prominent than heredity.
Journal of Clinical Medicine
Deformational plagiocephaly (DP) is considered a risk factor for facial asymmetry. This cohort-ba... more Deformational plagiocephaly (DP) is considered a risk factor for facial asymmetry. This cohort-based, prospective, follow-up study used three-dimensional (3D) stereophotogrammetry to assess the development of facial asymmetry in a normal birth cohort and to investigate the impact of DP on facial asymmetry for the age range of one to three years. The study sample consisted of 75 children: 35 girls (47%) and 40 (53%) boys recruited from Oulu University Hospital. A total of 23 (31%) subjects had a history of DP in infancy. 3D facial images were obtained at the mean (SD) age of 1.01 (0.04) year old at T1 and 3.02 (0.14) years old at T2. To determine facial asymmetry, both landmark-based and surface-based facial symmetry methods were used. As measured with the surface-based methods, upper facial symmetry improved from T1 to T2 (p < 0.05). As measured with the landmark-based methods, facial symmetry improved on the upper and lower jaw from T1 to T2 (p < 0.05). The asymmetric effect ...
Journal of Clinical Medicine
Preterm infants are at higher risk for both symmetrical and asymmetrical head molding. This study... more Preterm infants are at higher risk for both symmetrical and asymmetrical head molding. This study involved 3D stereophotogrammetry to assess the cranial growth, molding, and incidence of deformational plagiocephaly (DP) in preterm children compared to term born children. Thirty-four preterm infants and 34 term born controls were enrolled in this study from Oulu University Hospital, Finland. Three-dimensional head images were obtained at the age of 2–4 months (T1), 5–7 months (T2), 11–13 months (T3), and 2.5–3 years (T4) from the term equivalent age (TEA). There was no statistically significant difference in oblique cranial length ratio (OCLR), cephalic index (CI), or weighted asymmetry score (wAS) between the two groups. Occipital flattening, defined by flatness score (FS) was statistically significantly greater in the preterm group than in the term group at T1–T4 (p < 0.05). In both groups, OCLR improved gradually over time. There were no instances, in either group, of severe DP...
European Journal of Orthodontics
Objectives: To study, whether there are associations between chewing side preference and other la... more Objectives: To study, whether there are associations between chewing side preference and other lateralities, whether there is a genetic origin for preferred chewing side (PCS), relations to sex, birth order and orthodontic treatment. Materials and Methods: The study included 113 twin pairs, 57 pairs monozygotic, 47 pairs same sex dizygotic and 9 pairs of opposite sex. The lateralities of preferred chewing side, footedness and eyedness were assessed by functional tests and handedness was checked by asking. Results: Right-handed,-footed and-eyed as separated groups, and true-right sided (combined), were evenly distributed by preferred chewing side. By contrast, left-handed,-footed,-eyed and non-right sided used more left or both sides when chewing. Birth order affected preferred chewing side among monozygotic: the first-born twin was more likely to have the preferred chewing side on the non-right, whereas second-born twins used right side. Gender, zygosity and orthodontic treatment were not statistically significant factors. Limitations: Examination of chewing sidedness could have been done in several different ways to provide a definite result. Sample size of opposite sex twins was very small. Conclusions: Preferred chewing side generally seemed to follow the side where other lateralities occur; however, monozygotic twins seemed to be more receptive to it. True-right sided were more evenly distributed than non-right sided by the preferred chewing side.
Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery, Jan 22, 2017
Various measurements are used to quantify cranial asymmetry in deformational plagiocephaly (DP), ... more Various measurements are used to quantify cranial asymmetry in deformational plagiocephaly (DP), but studies validating cut-off values and comparing the accuracy of such measurements are lacking. In this study, we compared the accuracy of four different measurements in classifying children with and without DP diagnosed by visual assessment, and sought to determine their optimal cut-off values. Two experts rated 407 3D craniofacial images of children aged between 3 and 36 months old using the Argenta classification. We then measured the following asymmetry-related variables from the images: Oblique Cranial Length Ratio (OCLR), Diagonal Difference (DD), Posterior Cranial Asymmetry Index (PCAI), and weighted Asymmetry Score (wAS). We created receiver operating characteristic curves to evaluate the accuracy of these variables. All variables performed well, but OCLR consistently provided the best discrimination in terms of area under the curve values. Subject's age had no clear effec...
European Journal of Pediatrics, 2016
Deformational plagiocephaly is reported in up to 46.6 % of healthy infants, with the highest poin... more Deformational plagiocephaly is reported in up to 46.6 % of healthy infants, with the highest point prevalence at around 3 months of age. Few prospective studies on the natural course of skull deformation have been conducted, and we know of no studies using 3D imaging starting from the highest point prevalence period. In this prospective, population-based cohort study, we describe the course of cranial asymmetry and shape in an unselected population using 3D stereophotogrammetry and investigate factors associated with late cranial deformation and failure to recover from previous deformation. We evaluated 99 infants at 3, 6, and 12 months of age. We acquired 3D craniofacial images and performed structured clinical examinations and parental interviews at each visit. Eight outcome variables, representing different aspects of cranial shape, were calculated from a total of 288 3D images. Scores of asymmetry-related variables improved throughout the observation period. However, the rate of correction for cranial asymmetry decreased as the infants grew older, also in relation to the rate of head growth, and a significant amount of asymmetry was still present at 12 months. Positional preference at 3 months predicted an unfavorable course of cranial asymmetry after 3 months, increasing the risk for DP persisting. What is known: • The prevalence of deformational plagiocephaly spontaneously decreases after the first months of life. • Limited neck range of motion and infant positional preference increase the risk of deformational plagiocephaly during the first months of life. What is new: • Positional preference at 3 months predicts an unfavorable spontaneous course of deformation also from three to 12 months of age, presenting a potential target for screening and treatment. • The spontaneous rate of correction for cranial asymmetry decreases after 6 months of age, also in relation to the rate of head growth.
Statistics in Medicine, 2016
Infant skull deformation is analyzed using the distribution of head normal vector directions comp... more Infant skull deformation is analyzed using the distribution of head normal vector directions computed from a 3D image. Severity of flatness and asymmetry are quantified by functionals of the kernel estimate of the normal vector direction density. Using image data from 99 infants and clinical deformation ratings made by experts, our approach is compared with some recently suggested methods. The results show that the proposed method performs competitively. Copyright © 2016 John Wiley &amp; Sons, Ltd.
This study examined the relationship between the extensive use of forceps procedures during deliv... more This study examined the relationship between the extensive use of forceps procedures during delivery and later occlusal characteristics. The work uses data collected in National Collaborative Perinatal Research Project (USA), in which more than 60,000 pregnancies and the children&#39;s health were followed by regular medical tests and examinations. Of these, a subsample of 2,074 children participated in dental examinations, including the production of dental casts with wax bites to register occlusion. A total of 84 children, 55 boys and 29 girls, were coded as having undergone difficult or very difficult forceps deliveries. A control group was matched by age, sex, race, and site of dental examination. The results show a significant increase in asymmetric molar occlusion (P &lt; 0.005) and canine relations (P &lt; 0.001) in the study group. The sagittal length of the mandibular arch was increased in the difficult forceps delivery group (P &lt; 0.01). In conclusion, difficult forceps procedures are associated with a later asymmetric occlusion.
Early Human Development, Aug 1, 1992
Research area: The effects of genetic and dental disturbances on dental and craniofacial developm... more Research area: The effects of genetic and dental disturbances on dental and craniofacial development during pregnancy. Structural and functional lateralities
A comprehensive atlas, 2015
Twin research and human genetics : the official journal of the International Society for Twin Studies, Jan 14, 2015
The aim of this study was to compare facial 3D analysis to DNA testing in twin zygosity determina... more The aim of this study was to compare facial 3D analysis to DNA testing in twin zygosity determinations. Facial 3D images of 106 pairs of young adult Lithuanian twins were taken with a stereophotogrammetric device (3dMD, Atlanta, Georgia) and zygosity was determined according to similarity of facial form. Statistical pattern recognition methodology was used for classification. The results showed that in 75% to 90% of the cases, zygosity determinations were similar to DNA-based results. There were 81 different classification scenarios, including 3 groups, 3 features, 3 different scaling methods, and 3 threshold levels. It appeared that coincidence with 0.5 mm tolerance is the most suitable feature for classification. Also, leaving out scaling improves results in most cases. Scaling was expected to equalize the magnitude of differences and therefore lead to better recognition performance. Still, better classification features and a more effective scaling method or classification in dif...
European journal of pediatrics, 2015
Deformational plagiocephaly (DP) occurs frequently in otherwise healthy infants. Many infants wit... more Deformational plagiocephaly (DP) occurs frequently in otherwise healthy infants. Many infants with DP undergo physiotherapy or helmet therapy, and ample treatment-related research is available. However, the possibility of preventing DP has been left with little attention. We sought to evaluate the effectiveness of intervention in the newborn's environment, positioning, and handling on the prevalence of DP at 3 months and to investigate the causal relationship between DP and cervical imbalance. We carried out a randomized controlled trial, with healthy newborns randomized into two groups at birth. All families received standard positioning instructions to prevent SIDS. Additionally, the intervention group received detailed instructions regarding the infant's environment, positioning, and handling, with the goal of creating a nonrestrictive environment that promotes spontaneous physical movement and symmetrical motor development. Two- and three-dimensional photogrammetry serve...
Pediatric dentistry
This study examined the relationship between the extensive use of forceps procedures during deliv... more This study examined the relationship between the extensive use of forceps procedures during delivery and later occlusal characteristics. The work uses data collected in National Collaborative Perinatal Research Project (USA), in which more than 60,000 pregnancies and the children's health were followed by regular medical tests and examinations. Of these, a subsample of 2,074 children participated in dental examinations, including the production of dental casts with wax bites to register occlusion. A total of 84 children, 55 boys and 29 girls, were coded as having undergone difficult or very difficult forceps deliveries. A control group was matched by age, sex, race, and site of dental examination. The results show a significant increase in asymmetric molar occlusion (P < 0.005) and canine relations (P < 0.001) in the study group. The sagittal length of the mandibular arch was increased in the difficult forceps delivery group (P < 0.01). In conclusion, difficult forceps ...
Journal of dentistry for children (Chicago, Ill.)
The purpose of this study was to explore the sidedness of primary tooth horizontal wear facets be... more The purpose of this study was to explore the sidedness of primary tooth horizontal wear facets between the left and right sides of the dentition among 2 types of functionally lateralized (hand, foot, eye) children--those who were true right-sided (TRS), and partially or totally nonright-sided (NRS) at 4 years of age. Study subjects were 855 children with signs of wear in deciduous teeth on the dental casts (N=1,720) of the GOS (Genetic Odontometric Study of the Collaborative Perinatal) project, carried out in the 1960s in the United States by the National Institute of Neurological Disorders and Stroke (NINDS) in a cross-sectional manner at a mean age of 8(1/2) years (40% Caucasian and 60% African-American children). The statistical method used was chi-square analysis. Tooth wear was identified from dental casts in approximately 50% of cases. Wear was symmetric (equal on the right and left) in 49% of these dentitions, while asymmetric wear was found in 50%. Left-sided extra wear was ...
Orthodontics and Craniofacial Research, 2002
To explore deciduous tooth crown dimensions in strabismic children and the relationship between t... more To explore deciduous tooth crown dimensions in strabismic children and the relationship between the type of strabismus and tooth crown mesio-distal (M-D) and labio-lingual (L-L) size asymmetries. Dental casts at mixed dentition of 2159 Collaborative Perinatal Study black and white children were measured, 123 of them strabismic at 1 year of age, age ranging from 6 to 12 years. Directional and fluctuating asymmetries in antimeric teeth were explored in various types of strabismus having unilateral, bilateral or alternating expression. ANOVA and T-square test were used for size comparisons and calculated asymmetries were explored by comparing the variances and Pearson correlations. Strabismus was associated with significant M-D size increase of deciduous maxillary canines in black boys and white girls, black girls had size reduction in their mandibular canine, but white boys were unaffected. Right side size dominance was found in the strabismic children in the lower second deciduous molar M-D dimensions and in the children with alternating strabismus in their upper deciduous canine M-D dimensions. Children with unilateral strabismus had random fluctuating dental asymmetry in their upper deciduous second molar L-L dimensions when compared with healthy normals. Higher left-right correlations were found in lower second deciduous molar dimensions in strabismic girls when compared with that in controls and in strabismic boys, suggesting better developmental canalization in female. Asymmetries in the head area, such as promoted here in strabismic children, may have associations with asymmetries in the dentition, focusing the embryonal origins and timing of developmental processes.
Early Human Development, 1997
Research area: The effects of genetic and dental disturbances on dental and craniofacial developm... more Research area: The effects of genetic and dental disturbances on dental and craniofacial development during pregnancy. Structural and functional lateralities
Archives of Oral Biology, 2001
Dental casts and oral photographs from a cross-sectional sample of 2092 young North Americans wit... more Dental casts and oral photographs from a cross-sectional sample of 2092 young North Americans with detailed information on functional lateralities (eyedness, handedness and footedness) were examined to compare the proportions of symmetrical and asymmetrical eruption of the antimeric (left-right, contralateral pair) permanent teeth using a four-grade eruption scale. The proportion of symmetrically erupting antimeric teeth was higher for some teeth in those with non-right-sidedness of the feet and eyes, but not significantly so in the case of handedness. Left-footedness was significantly (95% confidence interval) associated with an increased proportion of symmetrical pairs of the maxillary first molar and mandibular lateral incisor, and non-right-eyedness with an increased proportion of symmetrical eruption and left/right non-balanced proportions of asymmetrical eruption in maxillary central incisors. True right-sidedness (hand, foot and eye) was significantly (P&lt; or =0.05) associated with advanced eruption of the left mandibular first molar. It is suggested that while the timing of antimeric tooth emergence and clinical eruption is primarily programmed before crown mineralization, starting approximately at the 30th gestational week in the case of first permanent molars, symmetrical/asymmetrical tooth emergence and eruption may provide information a posteriori on prenatal and early postnatal growth and development.
European Journal of Orthodontics, 2004
SUMMARY The aim of this study was to explore unilateral Angle II-type malocclusion prevalences in... more SUMMARY The aim of this study was to explore unilateral Angle II-type malocclusion prevalences in functionally true right-sided (TRS) and non-right-sided (NRS) children having one or more left-sided functions (eye, hand, foot). A half cusp sagittal relationship of the upper and lower M1 and Dm2 was determined on dental casts of 1423 young American black and white children in a
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Papers by Tuomo Heikkinen