Impact of Unilateral Alveolar Bone Grafting on Nasal Volume and Nasolabial Surface: A 3D Analysis.

OBJECTIVE: To determine possible effects of unilateral alveolar cleft closure on internal nasal volume and external nasolabial surface. DESIGN: Retrospective, single-arm, cohort study. SETTING: Institutional, tertiary care. PATIENTS: Patients with complete unilateral cleft lip, alveolus, and palate (CUCLAP), who underwent closure of the alveolar cleft with autologous bone graft (ABG) at the age of 9-11 years, with cone beam computed tomography (CBCT) and/or three-dimensional (3D) stereophotogrammetry images taken before and one year after the ABG procedure. INTERVENTIONS: ABG-pocedure in patients with CUCLAP. MAIN OUTCOME MEASURES: The influence of ABG on the internal and external nasal morphology. RESULTS: A total of 28 patients (21M/7F, 14R/14L) were divided into internal (CBCT) and external (3D-stereophotogrammetry) measurement subgroups. The external nasolabial surface showed a significant decrease of the angle alar curvature right-subnasale-alar curvature left (-1.99°; P = .02; 95% CI -2.61, -0.36) and an increase of the linear measurement between these points (+1.01 mm; P = .03; 95% CI: 0.11, 1.91). No significant differences were found when comparing the distance maps of the affected side with the non-affected side (P = .50, 95% CI: -0.20, 0.29). CONCLUSIONS: Closure of the alveolar cleft in CUCLAP patients with ABG did not affect the internal nasal volume, but significantly affected the external nasal surface. The procedure resulted in the nose becoming wider because both alar curvatures moved caudally and laterally relative to the subnasale.

[Diagnosis of ankylotic deciduous molars using intraoral scans in oligodontic patients]. / Diagnose van ankylotische melkmolaren met intraorale scans bij oligodontiepatiënten.

In this retrospective study, 2 intraoral scans with an interval of at least 1 year were superimposed in 25 oligodontic patients. The differences in vertical eruption (mm) were measured and the orthopantomograms were analyzed for the presence of ankylotic deciduous molars with no successor. The mean eruption of deciduous molars with and without successor was significantly lower than the mean eruption of permanent molars. The eruption of permanent molars was a predictive variable for the eruption of deciduous molars. The number of agenetic elements and the presence of a successor were strongly associated with the eruption of deciduous molars. Also, the mean eruption of deciduous molars with ankylosis was significantly lower than that of deciduous molars without ankylosis. This study showed a strong relationship between the diagnosis of ankylotic deciduous molars and the measurement of negative vertical eruption when monitored by intraoral scans.

Craniofacial morphology and growth in Muenke syndrome, Saethre-Chotzen syndrome, and TCF12-related craniosynostosis.

OBJECTIVES: To determine whether the midface of patients with Muenke syndrome, Saethre-Chotzen syndrome, or TCF12-related craniosynostosis is hypoplastic compared to skeletal facial proportions of a Dutch control group. MATERIAL AND METHODS: We included seventy-four patients (43 patients with Muenke syndrome, 22 patients with Saethre-Chotzen syndrome, and 9 patients with TCF12-related craniosynostosis) who were referred between 1990 and 2020 (age range 4.84 to 16.83 years) and were treated at the Department of Oral Maxillofacial Surgery, Special Dental Care and Orthodontics, Children's Hospital Erasmus University Medical Center, Sophia, Rotterdam, the Netherlands. The control group consisted of 208 healthy children. RESULTS: Cephalometric values comprising the midface were decreased in Muenke syndrome (ANB: ß = -1.87, p = 0.001; and PC1: p < 0,001), Saethre-Chotzen syndrome (ANB: ß = -1.76, p = 0.001; and PC1: p < 0.001), and TCF12-related craniosynostosis (ANB: ß = -1.70, p = 0.015; and PC1: p < 0.033). CONCLUSIONS: In this study, we showed that the midface is hypoplastic in Muenke syndrome, Saethre-Chotzen syndrome, and TCF12-related craniosynostosis compared to the Dutch control group. Furthermore, the rotation of the maxilla and the typical craniofacial buildup is significantly different in these three craniosynostosis syndromes compared to the controls. CLINICAL RELEVANCE: The maxillary growth in patients with Muenke syndrome, Saethre-Chotzen syndrome, or TCF12-related craniosynostosis is impaired, leading to a deviant dental development. Therefore, timely orthodontic follow-up is recommended. In order to increase expertise and support treatment planning by medical and dental specialists for these patients, and also because of the specific differences between the syndromes, we recommend the management of patients with Muenke syndrome, Saethre-Chotzen syndrome, or TCF12-related craniosynostosis in specialized multidisciplinary teams.

Dentition patterns in bilateral cleft lip subphenotypes: multicenter study.

OBJECTIVES: Here, we retrospectively investigated cases of bilateral oral clefts (OCs) to determine the clinical relevance of detailed distinction of incomplete cleft lip subphenotypes, based on morphological severity of the cleft, within the categories cleft lip with or without alveolus (CL ± A) and cleft lip, alveolus, and palate (CLAP). We further assessed possible associations between CL subphenotypes (complete vs different incomplete types) and different dentition patterns of the lateral incisor. MATERIALS AND METHODS: Our analysis included 151 non-syndromic Caucasian bilateral OC-patients (8-20 years old) from the Dutch Association for Cleft Palate and Craniofacial Anomalies registry. Six different deciduous and permanent lateral incisor patterns were distinguished: normal position (z/Z), supernumerary lateral incisor (n/N), presence in the anterior (x/X) or posterior (y/Y) segment of the cleft, one in each cleft segment (xy/XY), and agenesis (ab/AB). Logistic regression was performed to show the associations between the CL subphenotypes and dentition patterns of the lateral incisor. RESULTS: One hundred three had complete, while 48 had incomplete CLs. Patterns z/Z and n/N were associated with a submucous/vermillion notch, incomplete CL, and intact alveolus. Patterns x/X, y/Y, and xy/XY were most common in patients with two-thirds to subtotal CL and complete CL. The most severe pattern, ab/AB, was most commonly associated with complete CL. CONCLUSIONS: Based on the morphological severity of the CLs, it can be stated that the more severe the CL in bilateral CL ± A and CLAP, the more severe the abnormal pattern of the dentition. CLINICAL RELEVANCE: Further distinction of incomplete cleft lip subphenotypes (submucous/vermillion notch, one-third to two-thirds CL, two-thirds to subtotal CL) in bilateral CL ± A and CLAP has clinical relevance.

Fusion of intra-oral scans in cone-beam computed tomography scans.

PURPOSE: The purpose of this study was to evaluate the clinical accuracy of the fusion of intra-oral scans in cone-beam computed tomography (CBCT) scans using two commercially available software packages. MATERIALS AND METHODS: Ten dry human skulls were subjected to structured light scanning, CBCT scanning, and intra-oral scanning. Two commercially available software packages were used to perform fusion of the intra-oral scans in the CBCT scan to create an accurate virtual head model: IPS CaseDesigner® and OrthoAnalyzer™. The structured light scanner was used as a gold standard and was superimposed on the virtual head models, created by IPS CaseDesigner® and OrthoAnalyzer™, using an Iterative Closest Point algorithm. Differences between the positions of the intra-oral scans obtained with the software packages were recorded and expressed in six degrees of freedom as well as the inter- and intra-observer intra-class correlation coefficient. RESULTS: The tested software packages, IPS CaseDesigner® and OrthoAnalyzer™, showed a high level of accuracy compared to the gold standard. The accuracy was calculated for all six degrees of freedom. It was noticeable that the accuracy in the cranial/caudal direction was the lowest for IPS CaseDesigner® and OrthoAnalyzer™ in both the maxilla and mandible. The inter- and intra-observer intra-class correlation coefficient showed a high level of agreement between the observers. CLINICAL RELEVANCE: IPS CaseDesigner® and OrthoAnalyzer™ are reliable software packages providing an accurate fusion of the intra-oral scan in the CBCT. Both software packages can be used as an accurate fusion tool of the intra-oral scan in the CBCT which provides an accurate basis for 3D virtual planning.

Symmetry of palatal shape during the first year of life in healthy infants.

OBJECTIVES: The purpose of this study was to quantify the symmetry of the alveolar process of the maxilla and palate during the first year of life in healthy infants with the help of a semiautomatic segmentation technique. MATERIALS AND METHODS: Maxillary plaster models of seventy healthy babies at 0, 3, 6, 9, and 12 months were collected and digitized. A semiautomatic segmentation tool was used to extract the alveolus and palate. The resulting model was aligned within a reference frame and mirrored on its medial plane. Distance maps were created and analyzed to compare and quantify the differences between the two hemispheres. Additional hemispherical width and area measurements were performed. An ANOVA test with additional post hoc tests was performed to check if the symmetry changed during development. Finally, the results were tested on intra- and interobserver variability. RESULTS: The absolute mean inter-surface distance between the original and mirrored models in each age group ranged between 0.23 and 0.30 mm. Width and area analysis showed a small but significant larger left palatal hemisphere. ANOVA and post hoc tests showed no significant difference in symmetry between groups. Reliability analysis showed no significant differences between observers. CONCLUSIONS: This study showed that in this infant population, only a small degree of palatal asymmetry was present, which can be considered as normal and clinically irrelevant. CLINICAL RELEVANCE: The data from this study can be used in future comparative studies as reference data. Furthermore, modeling of these data can help in predicting the growth pattern, which may lead to improved treatment protocols for children with craniofacial anomalies.

Virtual setup in orthodontics: planning and evaluation.

OBJECTIVES: The purpose of this study was to evaluate the clinical accuracy of virtual orthodontic setups by using a new CBCT-based approach. MATERIALS AND METHODS: Ten patients who underwent pre-surgical orthodontics were included in this study. Pre-treatment and pre-surgical cone-beam CT (CBCT) scans and digital dental models were available. The pre-treatment digital dental model was used to create an orthodontic virtual setup. The digital dental models were fused with the corresponding CBCT scans, and the two CBCT scans were aligned using voxel-based matching. Moving each individual tooth from the virtual setup to the final outcome allows the calculation of the accuracy of the virtual setup by using an iterative closest point algorithm. Differences between virtual setup and final outcome were recorded as well as the ICC between two observers. RESULTS: The inter-observer variability showed a high level of agreement between the observers. The largest mean difference between observers was found in the cranial/caudal direction (0.36 ± 0.30 mm) and the roll rotation (1.54 ± 0.98°). Differences between the virtual setup and final outcome were small in the translational direction (0.45 ± 0.48 mm). Rotational mean differences were larger with the pitch of the incisors (0.00 ± 7.97°) and molars (0.01 ± 10.26°) as largest difference. Excessive extrusion of all upper teeth and more anterior movement than planned were seen for both upper and lower arch. Lower molars showed less extrusion. CLINICAL RELEVANCE: The data of this study can be used to obtain more insight in the accuracy and achievability of orthodontic virtual setup. Tooth movement can now be studied in more details which can lead to new insights.

Deviating dental arch morphology in mild coronal craniosynostosis syndromes.

OBJECTIVES: To determine whether the intramaxillary relationship of patients with Muenke syndrome and Saethre-Chotzen syndrome or TCF12-related craniosynostosis are systematically different than those of a control group. MATERIAL AND METHODS: Forty-eight patients (34 patients with Muenke syndrome, 8 patients with Saethre-Chotzen syndrome, and 6 patients with TCF12-related craniosynostosis) born between 1982 and 2010 (age range 4.84 to 16.83 years) that were treated at the Department of Oral Maxillofacial Surgery, Special Dental Care and Orthodontics, Children's Hospital Erasmus University Medical Center, Sophia, Rotterdam, the Netherlands, were included. Forty-seven syndromic patients had undergone one craniofacial surgery according to the craniofacial team protocol. The dental arch measurements intercanine width (ICW), intermolar width (IMW), arch depth (AD), and arch length (AL) were calculated. The control group existed of 329 nonsyndromic children. RESULTS: All dental arch dimensions in Muenke (ICW, IMW, AL, p < 0.001, ADmax, p = 0.008; ADman, p = 0.002), Saethre-Chotzen syndrome, or TCF12-related craniosynostosis patients (ICWmax, p = 0.005; ICWman, IMWmax, AL, p < 0.001) were statistically significantly smaller than those of the control group. CONCLUSIONS: In this study, we showed that the dental arches of the maxilla and the mandible of patients with Muenke syndrome and Saethre-Chotzen syndrome or TCF12-related craniosynostosis are smaller compared to those of a control group. CLINICAL RELEVANCE: To gain better understanding of the sutural involvement in the midface and support treatment capabilities of medical and dental specialists in these patients, we suggest the concentration of patients with Muenke and Saethre-Chotzen syndromes or TCF12-related craniosynostosis in specialized teams for a multi-disciplinary approach and treatment.

Three dimensional maxillary growth modeling in newborns.

OBJECTIVES: The aim of this study was to develop an accurate and intuitive semi-automatic segmentation technique to calculate an average maxillary arch and palatal growth profile for healthy newborns in their first year of life. MATERIALS AND METHODS: Seventy babies born between 1985 and 1988 were included in this study. Each child had five impressions made in the first year after birth that were digitalized. A semi-automatic segmentation tool was developed and used to assess the maxillary dimensions. Finally, random effect models were built to describe the growth and build a simulation population of 10,000 newborns. The segmentation was tested for inter- and intra-observer variability. RESULTS: The Pearson correlation coefficient for each of the variables was between 0.94 and 1.00, indicating high inter-observer agreement. The paired sample t test showed that, except for the tuberosity distance, there were small, but significant differences in the landmark placements between observers. Intra-observer repeatability was high, with Pearson correlation coefficients ranging from 0.87 to 1.00 for all measurements, and the mean differences were not significant. A third or second degree growth curve could be successfully made for each parameter. CONCLUSIONS: These findings indicated this method could be used for objective clinical evaluation of maxillary growth. CLINICAL RELEVANCE: The resulting growth models can be used for growth studies in healthy newborns and for growth and treatment outcome studies in children with cleft lip and palate or other craniofacial anomalies.

Disturbances of dental development distinguish patients with oligodontia-ectodermal dysplasia from isolated oligodontia.

OBJECTIVE: To investigate phenotypic differences in dental development between isolated oligodontia and oligodontia-ectodermal dysplasia (ED). SETTING AND SAMPLE POPULATION: A total of 129 patients diagnosed with isolated oligodontia and 22 patients with oligodontia as part of ED were eligible. METHODS: The phenotype of dental development was assessed for the frequency of missing a certain tooth, dental age, development of each tooth present, abnormal size and abnormal shape of teeth. The data were analysed building linear, ordinal and logistic regression models. RESULTS: Compared to patients with isolated oligodontia, patients with oligodontia-ED missed more frequently central incisors and second molars in both jaws, and lateral incisors in the mandible (P < .05). Oligodontia-ED was associated with delayed development of the permanent dentition (ß = -0.10; 95% CI: -0.17, -0.03). Specifically, the maxillary teeth: right central incisor, right lateral incisor, right second premolar and left second premolar were delayed approximately from 2 to 4 developmental stages. In addition, the left mandibular second premolar was 3 developmental stages delayed. Abnormal shape of teeth was 7 times more evident in patients with oligodontia-ED compared to patients with isolated oligodontia (OR = 6.54; 95% CI: 2.34, 18.28). The abnormal size of teeth was not a distinctive characteristic for oligodontia-ED. CONCLUSIONS: Oligodontia-ED distinguishes from isolated oligodontia by more disturbances in dental development. The abnormal shape of incisors and canines in a patient with oligodontia can raise suspicions for accompanying ectodermal abnormalities.

Dental development in Down syndrome and healthy children: a comparative study using the Demirjian method.

OBJECTIVE: In children with Down syndrome, the timing of dental eruption is important for orthodontics treatment planning. Aim of this study was to determine whether tooth eruption and development of the dentition in children with Down syndrome are impaired. MATERIAL AND METHODS: Dental development was scored on orthopantomograms (OPTs) of 95 children with Down syndrome. The dental age was determined at the left mandibular side according to the Demirjian method and by converting the assigned scores to the dental maturity score. Dental development scores of control children and DS children were compared with a mixed model linear regression analysis. RESULTS: The model showed statistically significant changes relating to increasing age (P<0.001) and gender (P<0.05). In this comparison, the total DS group (with and without hypodontia) was not statistically significantly different from the control group. There was also no significant difference between the total sample of DS children and the control group after using the Nyström imputation (with and without hypodontia). CONCLUSION: The findings showed that dental development in DS children is similar to the development of control children and that a relationship exists between hypodontia and dental development. The clinically observed late eruption is probably not due to late dental development but due to the other processes that take place during eruption, such as the possible impaired processes at the apical side and the occlusal side of an erupting element.

The relationship between craniofacial development and hypodontia in patients with Down syndrome.

BACKGROUND/OBJECTIVE: Hypodontia is often seen in people with Down syndrome (DS). In the normal population, persons with hypodontia have a shorter cranial base and a hypoplastic maxilla, leading to a skeletal Class III tendency and a reduced face height. The purpose of this study was to examine craniofacial morphology in patients with DS at different ages and the influence of hypodontia on their craniofacial morphology. MATERIALS AND METHODS: A comparative cross-sectional study was conducted in 63 children with DS (6-19 years old; 28 males and 35 females) at a Centre for Special Care Dentistry in Rotterdam, the Netherlands (CBT Rijnmond). Digital lateral cephalograms were obtained from all subjects and a cephalometric analysis was performed. The subjects were divided into a group with hypodontia (13 males and 25 females) and a group without hypodontia (15 males and 10 females). RESULTS: Significant results included a decrease in antero-posterior relationship of upper and lower jaw (ANB angle -0.331° per year, P = 0.044) and a decrease in vertical dimension (S-N_Go-Gn angle -0.72° per year, P = 0.039) over the years in subjects with hypodontia compared to subjects without hypodontia. CONCLUSION: The process of growth in DS patients is towards a reversed overjet. Hypodontia seems to have an additional effect on this development. The management of hypodontia as part of the complete treatment of dental development in DS children is important because it strongly influences the jaw relationship.

Transverse dental arch relationship at 9 and 12 years in children with unilateral cleft lip and palate treated with infant orthopedics: a randomized clinical trial (DUTCHCLEFT).

OBJECTIVE: A long-term evaluation to assess the transverse dental arch relationships at 9 and 12 years of age in unilateral cleft lip and palate treated with or without infant orthopedics (IO). The hypothesis is that IO has no effect on the transverse dental arch relationship. MATERIAL AND METHODS: A prospective two-arm randomized controlled trial (DUTCHCLEFT) in three academic cleft palate centers (Amsterdam, Nijmegen and Rotterdam, the Netherlands). Fifty-four children with complete unilateral cleft lip and palate and no other malformations were enrolled in this evaluation. One group wore passive maxillary plates (IO+) during the first year of life, and the other group did not (IO-). Until the age of 1.5, all other interventions were the same. Hard palate was closed simultaneously with bone grafting according to protocol of all teams. Orthodontic treatment was performed when indicated. The transverse dental arch relationship was assessed on dental casts using the modified Huddart/Bodenham score to measure the maxillary arch constriction at 9 and 12 years of age. RESULTS: No significant differences were found between the IO+ and IO- groups. Differences between the centers increased from 9 to 12 years of age. CONCLUSIONS: Transverse dental arch relationships at 9 and 12 years of age do not differ between children with UCLP treated with or without IO. CLINICAL RELEVANCE: There is no orthodontic need to perform IO as applied in this study in children with UCLP.

Mandibular asymmetry in patients with the crouzon or apert syndrome.

The aim of this study was to describe directional and fluctuating mandibular asymmetry over time in children with Crouzon or Apert syndrome. Mandibular asymmetry of children between 7.5 and 14 years of age with Crouzon syndrome (n = 35) and Apert syndrome (n = 24) were compared with controls (n = 327). From panoramic radiographs, mandibular directional and fluctuating asymmetry was determined for the three groups. Multilevel statistical techniques were used to describe mandibular asymmetry changes over time. Patients with Crouzon and Apert syndromes showed statistically significant more fluctuating asymmetry for mandibular measures than did controls. Between the Crouzon and Apert syndromes groups, no statistical differences were found in directional and fluctuating asymmetry. The control group showed statistically significantly more directional asymmetry than did patients with Crouzon or Apert syndrome. The controls showed no change over time for the directional asymmetry of condylar-ramal height; however, the directional asymmetry of the gonial angle increased. Patients with Crouzon syndrome showed side dominance for only condylar-ramal height; whereas, patients with Apert syndrome did not show dominance for any of the measurements. Apert and Crouzon syndromes showed developmental instability, in contrast to the controls. No statistically significant longitudinal differences were found for either the directional or the fluctuating asymmetry between Crouzon and Apert syndromes. Findings for fluctuating and directional asymmetry for both syndromes may indicate an inability to cope with genetic and environmental stress during development and treatment, compared with untreated nonsyndromic individuals.

Oral health-related quality of life in patients with oligodontia: A FACE-Q assessment.

OBJECTIVES: The present study aimed to investigate the impact of oligodontia on appearance and on the functional and psychosocial aspects of oral health-related quality of life (OHrQoL) in patients aged 8-29 years. METHODS: 62 patients with oligodontia that were registered at Radboud University Medical Center, Nijmegen, The Netherlands were included. A control group included 127 patients that were referred for a first orthodontic consultation. Participants completed the FACE-Q Dental questionnaire. Regression analyses were performed to explore relationships between OHrQoL and patient-identified gender, age, the number of congenitally missing teeth, active orthodontic treatment, and previous orthodontic treatment. RESULTS: The only clear significant difference between the oligodontia and control groups was that patients with oligodontia scored lower in the domain, 'eating and drinking' (p < 0.001). It was found that, in oligodontia, the greater the number of agenetic teeth, the more difficulties eating and drinking. In fact, the Rasch score was reduced by 1.00 (95% CI: 0.23-1.77; p = 0.012) for each extra agenetic tooth. Older children scored significantly lower than younger ones on five out of nine scales: appearance of the face, smile, and jaws; social function; and psychological function. Females scored significantly lower than males on four scales: appearance of the face, appearance distress, social function, and psychological function. CONCLUSION: These findings suggested that, when treating patients with oligodontia, the number of agenetic teeth, age, and gender should be taken into account. These factors could have negative effects on their self-assessment of appearance, their facial function, and their quality of life. CLINICAL SIGNIFICANCE: The increased difficulty with eating and drinking associated with more agenetic teeth highlighted the importance of functional (re)habilitation.

Stem cells and extracellular vesicles to improve preclinical orofacial soft tissue healing.

Orofacial soft tissue wounds caused by surgery for congenital defects, trauma, or disease frequently occur leading to complications affecting patients' quality of life. Scarring and fibrosis prevent proper skin, mucosa and muscle regeneration during wound repair. This may hamper maxillofacial growth and speech development. To promote the regeneration of injured orofacial soft tissue and attenuate scarring and fibrosis, intraoral and extraoral stem cells have been studied for their properties of facilitating maintenance and repair processes. In addition, the administration of stem cell-derived extracellular vesicles (EVs) may prevent fibrosis and promote the regeneration of orofacial soft tissues. Applying stem cells and EVs to treat orofacial defects forms a challenging but promising strategy to optimize treatment. This review provides an overview of the putative pitfalls, promises and the future of stem cells and EV therapy, focused on orofacial soft tissue regeneration.

Novel Genetic Determinants of Dental Maturation in Children.

Dental occlusion requires harmonious development of teeth, jaws, and other elements of the craniofacial complex, which are regulated by environmental and genetic factors. We performed the first genome-wide association study (GWAS) on dental development (DD) using the Demirjian radiographic method. Radiographic assessments from participants of the Generation R Study (primary study population, N1 = 2,793; mean age of 9.8 y) were correlated with ~30 million genetic variants while adjusting for age, sex, and genomic principal components (proxy for population stratification). Variants associated with DD at genome-wide significant level (P < 5 × 10-8) mapped to 16q12.2 (IRX5) (lead variant rs3922616, B = 0.16; P = 2.2 × 10-8). We used Fisher's combined probability tests weighted by sample size to perform a meta-analysis (N = 14,805) combining radiographic DD at a mean age of 9.8 y from Generation R with data from a previous GWAS (N2 = 12,012) on number of teeth (NT) in infants used as proxy of DD at a mean age of 9.8 y (including the ALSPAC and NFBC1966). This GWAS meta-analysis revealed 3 novel loci mapping to 7p15.3 (IGF2BP3: P = 3.2 × 10-8), 14q13.3 (PAX9: P = 1.9 × 10-8), and 16q12.2 (IRX5: P = 1.2 × 10-9) and validated 8 previously reported NT loci. A polygenic allele score constructed from these 11 loci was associated with radiographic DD in an independent Generation R set of children (N = 703; B = 0.05, P = 0.004). Furthermore, profiling of the identified genes across an atlas of murine and human stem cells observed expression in the cells involved in the formation of bone and/or dental tissues (>0.3 frequency per kilobase of transcript per million mapped reads), likely reflecting functional specialization. Our findings provide biological insight into the polygenic architecture of the pediatric dental maturation process.

The frequency of Le Fort I osteotomy in cleft patients.

OBJECTIVE: The aim of this research was to study the frequency of Le Fort I osteotomy (LFI) in cleft patients treated according to the protocol of the Erasmus University Medical Center, Rotterdam. DESIGN: Retrospective cohort study. Patients : 508 cleft patients born between January 1, 1983, and December 31, 1992, were evaluated. MAIN OUTCOME MEASURES: Frequency of LFI and correlations with type and extent of cleft, gender, number of previous surgical procedures, age during alveolar augmentation, and missing teeth, respectively. RESULTS: 251 patients met the inclusion criteria. Overall, 28 of the 251 patients (11.2%) required LFI: none for cleft lip (0.0%); 2 of 43 (4.7%) for cleft lip and alveolus; 24 of 100 (24.0%) for cleft lip, alveolus, and palate; 2 of 50 (4.0%) for cleft palate; and none for submucous clefts or the miscellaneous group (0.0%). The frequency of LFI increased with the severity of the cleft type. The number of previous surgical interventions is significantly higher in cases with an indication for LFI (p < .001). The frequency of LFI is significantly higher in male cleft patients (p < .05). CONCLUSIONS: The overall frequency of LFI in the study group was 11.2%; this increased with the severity of the cleft type. A significant difference was noted in the number of previous surgical interventions between patients with and without an indication for an LFI. Delayed closure of the hard palate in the protocol might have influenced the low frequency of LFI.

Assessment of volumetric changes with a best-fit method in three-dimensional stereophotograms.

OBJECTIVE: Different three-dimensional stereophotogrammetry systems and analyzing methods exist that often use landmarks for comparison. Measurement errors in landmark or surface comparison are mostly within 1 mm, which seems clinically acceptable. The aim of this study was to validate a three-dimensional stereophotogrammetric best-fit method of assessing volumetric changes and to compare three devices. METHODS: The validation of the best-fit method was at first done on a life-size dummy head. Scans were made in the ideal position, as well as in four additional positions, and a scan was made in which a soft putty specimen was added to the dummy head. The comparison was executed with a best-fit method using triangulation. Student's t tests were used to detect statistically significant differences. Second, comparisons were made among scans of a white man in the ideal position and with volume changes added. RESULTS: The different positions tested for the dummy head showed no significant volume differences within each system or among systems. The differences found when adding a soft putty specimen fell into the same range as the differences between various positions. The differences within a live situation were 10 times greater compared with the dummy-head situation. CONCLUSIONS: In a dummy-head situation, the different systems gave similar results when tested with a best-fit method. However, in live situations the differences may become 10 times greater, possibly due to different facial expressions. These differences may become clinically relevant and, therefore, further research in volumetric changes is needed.