Comparing tooth development timing between ethnic groups, excluding nutritional and environmental influences.

The timing of dental development in ethnic Finns and Somalis, who were born and living in Finland, was compared, with efforts to minimize environmental bias. The developmental status of seven lower left permanent teeth were staged according to Demirjian et al., using panoramic radiographs from 2,100 Finnish and 808 Somali females and males, aged 2 to 23 years. For each tooth, a continuation-ratio model was constructed to analyze the allocated stages as a function of sex and ethnic origin. Several statistically significant differences in mean age of certain tooth developmental stage transitions were revealed. While Somalis generally displayed stage transitions at younger age, none of the seven teeth consistently showed earlier stage transitions in Somalis compared to Finns. Within each tooth, the lowest (or highest) mean age of stage transition varied without any discernible pattern between the two ethnic groups. Overall, the observed differences in mean age of stage transition between the groups was minimal, suggesting a low impact on clinical and forensic age assessment practice. In conclusion, the studied ethnic Finn and Somali groups with equal nutritional and /or environmental conditions exhibit similar timing in the development of all lower left permanent teeth.

The effect of optimum, indication-specific imaging fields on the radiation exposure from CBCT examinations of impacted maxillary canines and mandibular third molars.

OBJECTIVE: Indication-specific optimum field-of-views (FOVs) have been assessed for CBCT scans of impacted maxillary canines and mandibular third molars, as 40∅ × 35 mm and 35∅ × 35 mm, respectively. The objective was to investigate possible changes in absorbed organs and effective doses, for these two imaging indications, performing CBCT examinations with optimum FOV sizes instead of commonly used FOVs. Additionally, radiation exposure-induced cancer risk was calculated for both imaging indications with optimum FOVs. METHODS: An adult female head phantom (ATOM 702-D, CIRS, Norfolk, VA, USA) was scanned using Planmeca Viso G7 CBCT-device (Planmeca, Helsinki, Finland). Scanning factors, different FOV sizes, dose-area product (DAP) values and anatomical FOV locations were used for Monte Carlo PCXMC-simulation and ImpactMC software. In the PCXMC- simulation, 10-year-old child and 30-year-old adult phantoms were used to estimating effective and absorbed organ doses. RESULTS: The effective dose varied from 58 µSv to 284 µSv for impacted maxillary canines, and from 38 µSv to 122 µSv for mandibular third molars, the lowest dose value for each corresponding to optimum FOV. Effective dose reduction between the optimum FOV and the smallest common FOV of 50∅ × 50 mm, maintaining other scanning factors constant, was 33% for impacted maxillary canines, and 45% for mandibular third molars. At all examinations, the highest absorbed organ doses were in salivary glands or in oral mucosa. CONCLUSIONS: Optimum FOVs, 40∅ × 35 mm for impacted maxillary canine and 35∅ × 35 mm for mandibular third molar, could decrease effective doses received by young patients, and improve radiation safety in these common CBCT imaging procedures.

Costs and duration of orthodontic-surgical treatment with mandibular advancement surgery.

OBJECTIVES: The aim was to analyse the costs and duration of orthodontic-surgical treatment with mandibular advancement in the public health care sector in Finland. MATERIALS: The study was conducted as a retrospective registry study in a public district hospital on all nonsyndromic patients that were ethnic Finns and treated with full fixed appliances and mandibular advancement surgery in 2016-2020. RESULTS: The mean treatment duration of the included 45 patients was 28.1 months, including 18.9 months pre and 9.2 months postoperative orthodontics. The median number of visits was 27, including 17 visits before and 9 visits after surgery. The mean total treatment time was 14.5 h. The mean total direct costs per course of treatment were 7574 € to the municipality and 947 € to the patient. The costs positively correlated with the duration of the treatment (rho = 0.71, P = .000), but were not associated to gender or age of patient. The mean surgery time was 78 minutes, and significantly less with an experienced surgeon (P = .002). It was calculated that the mean minimum treatment costs would be 45% of the present total, achievable with a patient with optimum dental arches at the start of treatment. LIMITATIONS: The major limitation of the study is the relatively small number of study subjects. CONCLUSION: A 55% share of the costs is influenced by case- and operator-dependent factors. This indicates that the complexity and performance of the orthodontic phases of treatment are important determinants in the cost structure.

The impact of orthodontic treatment on choosing a career in dentistry.

INTRODUCTION: Many studies, globally, have aimed at elucidating reasons to choose a career in dentistry. The most common motives found are reasonable working hours and aspiration to help. The aim of this study was to explore whether eventual past personal experience of orthodontic treatment and particularly the interpersonal skills of the treating orthodontist are of significance in this respect. MATERIALS AND METHODS: An electronic questionnaire, consisting of multiple choice and descriptive questions about dental history and experiences in dental care, was sent to dental and, as controls, psychology students within the same Faculty of Medicine, University of Helsinki, Finland. The answers between the two groups were compared and differences tested statistically. RESULTS: The questionnaire was answered by 143 (46.0%) dental students and 94 (17.6%) psychology students. Dental students, compared to psychology students, had more positive views of their dentition and dental treatment in general (p = 0.000). Amongst participants, 47.9% of dental students and 57.4% of psychology students had received orthodontic treatment. Of those, dental students had perceived their orthodontic treatment as less painful (p = 0.001) and less uncomfortable (p = 0.000) than psychology students. Moreover, dental students reported more often experiences of orthodontist taking into account their situation in life during treatment (p = 0.011) and gave more positive descriptions of the orthodontist's interpersonal skills (p = 0.031). CONCLUSIONS: Dental students, compared to psychology students, had statistically significantly more positive personal experiences related to dentistry and orthodontics, supporting our hypothesis that positive experiences with orthodontic treatment likely increase the probability of choosing dentistry as the future career.

Dental and dentoalveolar dimensions in individuals with osteogenesis imperfecta.

OBJECTIVE: This cross-sectional study compared tooth and dental arch dimensions of individuals with Osteogenesis imperfecta (OI) and healthy controls. MATERIAL AND METHODS: The 37 OI patients and 37 controls were aged 10 to 74 years. Mesio-distal tooth size, dental arch dimensions, and palatal height were measured from dental models. The differences between the patient and control groups were analysed statistically with a t-test, chi-square test, and Mann-Whitney U test. RESULTS: The average mesio-distal tooth size of individuals with OI was smaller by 0.1 to 0.8 mm, corresponding to 1.4 to 7.3% of the size of the tooth. The patients and controls showed similar anterior-posterior lengths of maxillary and mandibular arches. The OI patient group exhibited increasingly wider maxillary dental arches posterior to the canines and a shallow palate. CONCLUSIONS: Reduced tooth size is a developmental feature of OI and a shallow palate a characteristic possibly associated with previously documented imparity of vertical jaw development. Observed posterior widening of the dental arches may follow from altered tongue position. Smaller tooth size can be favourable from orthodontic point of view in alleviating crowding, but it might further predispose to fracturing of teeth which is a considerable risk associated with dentine abnormality. The shallow jawbones may initiate development of posterior open bite, rare in general population but relatively often encountered in OI.

Minimum size and positioning of imaging field for CBCT-scans of impacted lower third molars: a retrospective study.

BACKGROUND: Cone-beam Computed Tomography (CBCT) is widely used for preoperative 3D imaging of lower third molars. Hence, for this imaging indication, the present study aimed to define the minimum field-of-view (FOV) size and its optimum placement, to decrease radiation exposure, and highlight the need of computer-assisted FOV centering technique for dental CBCT devices. To facilitate proper placement of image field, lower second molar was chosen as reference. METHODS: The retrospective study included 50 CBCT-scans of 46 patients with mean age of 34 years. Based on the lower second molar, a three-dimensional coordinate was formed and the location of mandibular canal (MC) and the dimensions and locations of the lower third molars, and possible associated pathological findings were assessed. Accordingly, the FOV size and position for third-molar imaging were optimized, while ensuring encompassment of all relevant structures. RESULTS: The minimum cylindrical volume, covering lower third molars and MC, was 32.1 (diameter) × 31.6 (height) mm, placed in relation to the second molar crown, top 2.2 mm above cusp tips, anterior edge 6.7 mm in the front of the most distal point of the crown, and lingual edge 7.9 mm on the medial side of the lingual wall. CONCLUSIONS: The optimized FOV for lower third molars was smaller than common standard small FOVs. We recommend using FOV volume 3.5∅ × 3.5 cm for third molars without associated pathology. Accurate FOV protocols are essential for development of new CBCT-devices with computer-assisted and indication-specific FOV placement.

Minimum size and positioning of imaging field for CBCT scans of impacted maxillary canines.

OBJECTIVES: In children and adolescents, cone-beam computed tomography (CBCT) is frequently used for localization of unerupted or impacted teeth in the anterior maxilla. CBCT causes a higher radiation dose than conventional intraoral and panoramic imaging. The objective was to analyze the location of impacted canines in a three-dimensional coordinate and thereby optimize the CBCT field-of-view (FOV), for radiation dose reduction. MATERIALS AND METHODS: Location of 50 impacted maxillary canines of children under 17 years was retrospectively evaluated from CBCT scans. The minimum and maximum distances of any part of the right- and left-side canines to three anatomic reference planes were measured to assess the adequate size and position of a cylindrical image volume. RESULTS: A cylinder sized 39.0 (diameter)×33.2 (height) mm, with its top situated 13.8 mm above the hard palate, its medial edge 8.4 mm across the midline, and anterior edge 2.5 mm in front of the labial surface of maxillary central incisors fitted all the analyzed canines. CONCLUSIONS: In this sample, the FOV required for imaging maxillary impacted canines was smaller than the smallest FOV offered by common CBCT devices. We encourage development of indication-specific CBCT imaging programs and aids to facilitate optimum patient positioning. CLINICAL RELEVANCE: An impacted maxillary canine is a common dental problem and a frequent indication for 3D imaging particularly in growing individuals. This article focuses on the optimization of CBCT of impacted canines. Our recommendation of a reduced FOV promotes radiation safety.

Dental age estimation in Somali children and sub-adults combining permanent teeth and third molar development.

Estimation of an individual's age has important applications in forensics. In young individuals, it often relies on separate evaluations of permanent teeth (PT) and third molars (TM) development. Here, we analysed the age prediction performance of combined information from PT and TM in an unusual sample of healthy Somalis, born and living in Finland. PT development was staged according to Demirjian et al. (Hum Biol, 1973) and TM development according to Köhler et al. (Ann Anat, 1994), using panoramic radiographs from 803 subjects (397 males, 406 females) aged 3-23 years. A sex-specific Bayesian age-estimation model for the multivariate distribution of the stages conditional on age was fitted on PT, TM and PT and TM combined. The age-estimation performances were validated and quantified. The approach combining PT and TM only overestimated age with an ME of - 0.031 years in males and - 0.011 years in females, indicating the best age prediction performance.

Dental age estimation in Somali children using the Willems et al. model.

AIM: The aim of the current study was to retrospectively collect dental panoramic radiographs from Somali children living in Finland, to use the radiographic data to develop a new age estimation model based on the model established by Willems et al. (J Forensic Sci 46(4):893-895, 2001), and to compare the age prediction performances of the Willems et al. model (WM) and the newly developed model. MATERIAL AND METHODS: Dental panoramic radiographs from 808 healthy Somalis born in Finland were selected. The development of the seven left mandibular permanent teeth, from the central incisor to the second molar, was staged according to Demirjian et al. (Hum Biol 45(2):211-227, 1973). Radiographs with all listed permanent teeth completely developed were excluded. The studied sample consisted of 635 subjects (311 females, 324 males) ranging in age from 4 to 18 years. Kappa and weighted Kappa statistics were used to quantify intra- and inter-observer agreement in stage allocation. The collected dataset was used to validate the WM, constructed on a Belgian Caucasian reference sample, and to establish a Somali-specific age estimation model (SM) based on the WM. Both models were validated and their age prediction performances quantified using mean error (ME), mean absolute error (MAE) and root mean squared error (RMSE). RESULTS: The SM resulted in a slight underestimation of age when the sex groups were analysed separately or combined, with ME varying between 0.04 (standard deviation (SD) 1.01) and 0.05 (SD 1.04) years, MAE between 0.77 and 0.80 years and RMSE between 1.01 and 1.04 years. The WM statistically significantly underestimated the age of females, with an ME of 0.20 (SD 1.01) years (p = 0.0006). For males, and for females and males combined, no statistically significant ME was observed. CONCLUSION: The WM and SM were similar in their age prediction performances, and the use of the WM in dental age assessment in the Somali population is justified.

Forensic age assessment of asylum seekers in Finland.

In Finland, forensic age assessment is strictly regulated by legislation. According to the Aliens Act (301/2004) and the amendment of the Act (549/2010), the police authorities, the frontier guard authorities, and the immigration authorities have the right to refer asylum seekers to the University of Helsinki, Department of Forensic Medicine, for age assessment. These assessments are especially performed to solve if the person is of major age, the cutoff being 18 completed years. The forensic age assessment is largely based on dental development, since the special permit of the Radiation and Nuclear Safety Authority (STUK) to the Department of Forensic Medicine of the University of Helsinki, allowing the use of ionizing radiation for non-medical purposes, includes dental and hand X-rays. Forensic age assessment is always performed by two forensic odontologists. In 2015, the total number of forensic age assessment examinations was 149, and the countries of origin of the asylum seekers were most commonly Iraq, Afghanistan, and Somalia. The current legislation on forensic age assessment has been well received and approved. Radiological and other examinations can be performed in different parts of Finland, but the forensic odontologist at the University of Helsinki is always involved in the process and ensures joint quality standards for the forensic age assessment.

Type and location of findings in dental panoramic tomographs in 7-12-year-old orthodontic patients.

OBJECTIVE: The Radiation and Nuclear Safety Authority in Finland has paid attention to the large numbers of dental panoramic tomographs (DPTs), particularly in 7-12-year-old children. The majority of these radiographs are taken for orthodontic reasons. Because of the high radiosensitivity of children, the size of the irradiated field should be carefully chosen to yield the necessary diagnostic information at the lowest possible dose. The purpose of the present study was, therefore, to assess the outcome of DPTs within this age group in terms of type and location of pathological findings. It was also hypothesized that DPTs of orthodontic patients rarely display unrestored caries. MATERIALS AND METHODS: Four hundred and forty-one DPTs, taken of 7-12-year-old children in 2010-2014, were randomly sampled. The 413 of them (94%) that had been taken for orthodontic reasons were analysed. RESULTS: All pathologic findings were restricted to the tooth-bearing area and there was no pathology in the bone structure or any incidental findings in the region of temporomandibular joint. Unlike hypothesized, 27% of the orthodontic DPTs showed caries in deciduous teeth and 16% in permanent teeth. A sub-sample of 229 DPTs, analysed for developmental dental and occlusal problems, most commonly displayed crowding (50%), positional anomalies and local problems with tooth eruption (32%), as well as hyperodontia (15%). CONCLUSION: Inclusion of only the actual area of interest in the image field should be considered case-specifically as a means to reduce the radiation dose.

Quality assessment of orthodontic radiography in children.

OBJECTIVES: Numbers of dental panoramic tomographs (DPTs) and lateral cephalometric radiographs (LCRs) outweigh other radiographic examinations in 7- to 12-year-old Finns. Orthodontists and general practitioners (GPs) involved in orthodontics hold therefore the highest responsibility of the exposure of children to ionising radiation with its risks. Against this background, lack of reports on the quality of orthodontic radiography is surprising. The purpose of our study was to shed some light and draw the awareness of the orthodontic community on the subject by analyzing the quality of orthodontic radiography in Oral Healthcare Department of City of Helsinki, in the capital of Finland. MATERIALS AND METHODS: We analyzed randomly selected 241 patient files with DPTs and 118 patient files with LCRs of 7- to 12-year-olds for the indications of radiography, quality of referrals, status of interpretation, and number of failed radiographs. RESULTS: The majority of DPTs (95%) and all LCRs had been ordered for orthodontic reasons. Of the DPTs, 60% were ordered by GPs, and of the LCRs, 64% by orthodontists. The referrals were adequate for most DPTs (78%) and LCRs (73%), orthodontists being responsible for the majority of inadequate referrals. Of the DPTs, 80% had been interpreted. Of the LCRs, 65% lacked interpretation, but 67% had been analysed cephalometrically. Failed radiographs, leading to repeated exposure, were found in 2-3%. CONCLUSION: The quality assessment revealed that orthodontic radiography may not completely fulfill the criteria of good practice. Our results stress further need of continuing education in radiation protection among both orthodontists and GPs involved in orthodontics.

Are children's dental panoramic tomographs and lateral cephalometric radiographs sufficiently optimized?

OBJECTIVES: Children are especially vulnerable to harmful effects of ionizing radiation. Cutting down the dimensions of the X-ray beam is the most effective way to reduce the patient dose. We evaluated the appropriateness of field-size in the most frequent radiographs, dental panoramic tomographs (DPTs) and lateral cephalometric radiographs (LCRs) among 7- to 12-year-olds. MATERIALS AND METHODS: The image field-size of 241 DPTs and 118 LCRs was analysed. The image field was considered appropriate when it did not include anatomic structures beyond the area of clinical interest. The image field was compared with factors such as the age of the patient, the radiographic equipment used and the programme selected. Moreover, we assessed the use of thyroid shield in LCR. RESULTS: The field-size was too large in 70% of the DPTs horizontally and in 96% vertically. None of the DPTs were segmented. Every LCR showed appropriate limitation anteriorly, but the image field was too large in 54% posteriorly, in 86% superiorly, and in 76% inferiorly. A thyroid shield had been used in only 71% of cases. CONCLUSION: Most DPTs and LCRs had been performed sub-optimally. An abundancy of DPTs had been taken using an adult programme, and the field-size had not been sufficiently adjusted in LCRs, possibly for technical reasons. To facilitate adherence to radiological best practice the equipment used for DPTs and LCRs should facilitate the adjustment of field-size in both the vertical and horizontal planes. In addition, those involved in taking radiographs should maintain their skills through regular update courses.

Effects of a 2-Year Early Childhood Vitamin D3 Intervention on Tooth Enamel and Oral Health at Age 6-7 Years.

INTRODUCTION: The aim of the study was to compare the effects of a 30 µg/day versus 10 µg/day vitamin D supplementation, given during the two first years of life, on oral health at the age of six to 7 years. METHODS: In 2013-2016, we conducted a randomized, double-blinded, clinical trial from age 2 weeks to 2 years of daily vitamin D3 supplementation (10 vs. 30 µg), including 975 healthy infants. For the present follow-up study at age 6-7 years, a sample of 123 children underwent oral examination by investigators blinded to the intervention group. Tooth enamel defect and caries findings, oral rinse active matrix metalloproteinase-8 levels, and tooth eruption were recorded. The intervention groups were compared with χ2 and Mann-Whitney U tests. Associations of the oral health outcomes were evaluated with correlation analysis and logistic regression. RESULTS: Of the children (median age 7.4 years, 51% boys), 56% belonged to the 30 µg intervention group. Developmental defect of enamel (DDE) was found in 39% of the children in the 10 µg intervention group and in 53% of the 30 µg group (p = 0.104). In total, 94% of children were vitamin D sufficient (25[OH]D ≥50 nmol/L) and 88% had caries-free teeth. No associations were found between vitamin D intervention group in infancy and oral health or the presence of DDE. CONCLUSION: Daily supplementation with 10 µg vitamin D3 in the Northern Hemisphere seems adequate in healthy children younger than 2 years in ensuring good oral health at early school age.

Cephalometric analysis of pharyngeal airway space dimensions in Turner syndrome.

Turner syndrome (TS) that is due to a total or partial lack of an X chromosome affects about 1 in 2000 girls. The syndrome is characterized by short stature and gonadal dysgenesis. Its documented craniofacial features include retrognathic jaws, a short mandible, and a large cranial base angle. Our aim was to find out whether the syndrome also has an effect on the pharyngeal airway space. We retrospectively analysed lateral cephalograms of 35 TS subjects whose age ranged from 6.5 to 21 years and of 35 healthy female controls matched for age. On those, we did 7 linear and 10 angular cephalometric measurements and 9 pharyngeal measurements. Differences between the subjects with TS and their controls were assessed by paired two-tailed T-test. In the girls with TS, both the maxilla and the mandible were more retrognathic (SNA, P = 0.015 and SNB, P < 0.001), the mandible was shorter (TM-Pgn, P = 0.016), and the cranial base angle was larger (SNBa, P = 0.025) than in the controls, confirming the results of earlier studies. Notably, all six pharyngeal airway measurements were smaller in girls with TS. Two of them, PNS-ad2 and PAS, were statistically significantly smaller (P = 0.019 and P = 0.012, respectively). Thus, a narrow pharynx, either as a primary finding or as a consequence of the maxillo-mandibular retrognathism, further delineates the phenotype. This may imply an elevated risk of sleep apnoea in females with TS.

Dimensions of the craniocervical junction in longitudinal analysis of normal growth.

INTRODUCTION: Abnormal configuration of the craniocervical junction in the form of basilar impression or invagination, with often-associated platybasia, is a clinically significant cause of neurological symptoms particularly in patients with inherited diseases affecting the connective tissue. To better understand the course of development of these basilar abnormalities and further define their diagnostic criteria in children, we analysed longitudinally changes in the vertical dimensions of the craniocervical junction and in the flexion of the anterior skull base in normal growing individuals. METHODS: The distance of the odontoid process to four reference lines and the anterior skull base angle was measured in consecutive series of at least five lateral skull radiographs of 30 females and 23 males. Their mean age was 6.4 years at the beginning and 22.4 years at the end of the observation period. RESULTS: In young children, the odontoid process was situated in a caudal relation to the skull base structures and reached a level similar to that of adults approximately at the age of 7 years in both males and females. Cross-sectional observation of the results camouflages, however, how the intra-individual changes were markedly non-linear. Changes in the anterior skull base angle remained nonsignificant. CONCLUSIONS: Normal values for McRae's, Chamberlain's and McGregor's measurements and the more recently documented D-M measurement are age dependent. We provide reference values specific for ages from 4 years. A notable deviation from the documented values indicates a need of further examination.

The Association between Molar-Incisor Hypomineralization and Dental Caries with Socioeconomic Status as an Explanatory Variable in a Group of Finnish Children.

The aim of this study was to investigate if a developmental enamel defect known as Molar-Incisor Hypomineralization (MIH) is associated with dental caries. Socioeconomic status (SES) was examined as a confounding factor between caries and MIH. In this cross-sectional study, 636 children, aged 8 to 13 years, from three towns (two rural areas and one urban area) in Finland were examined for MIH in line with the criteria of the European Academy of Paediatric Dentistry. Caries status for permanent teeth was recorded as decayed, missing and filled teeth (DMFT). Caries experience (DMFT > 0) in the first permanent molars (FPMs) was set as an outcome. SES was determined using a questionnaire completed by parents. The prevalence of MIH was 18.1%. The mean DMFT in FPMs for children with MIH was higher than for their peers, 1.03 ± 1.25 vs. 0.32 ± 0.80 (p = 0.000, Mann-Whitney U test). In a multivariate analysis using the generalized linear mixed model where locality, SES, age and MIH were taken into account as caries risk indicators, MIH was the strongest risk indicator of caries in FPMs (Odds Ratio: 6.60, 95% Confidence Interval: 3.83⁻11.39, p = 0.000). According to the study results, children with MIH have a higher risk for dental caries than children without MIH.

Timing of dental development in osteogenesis imperfecta patients with and without bisphosphonate treatment.

Bisphosphonates have established their role as medical therapy for pediatric osteogenesis imperfecta (OI) patients. Since bisphosphonates have also been shown to delay tooth development in animal models, we aimed to assess whether the medication has a similar effect on children with OI. In this cross-sectional study, bisphosphonate-treated OI patients of whom dental panoramic tomograph was taken between 3 and 16years of age formed the study group. The patients, 22 in total, had been treated with pamidronate, zoledronic acid or risedronate for at least one year before the radiography. Developmental stage of the permanent teeth, resorption of the deciduous teeth, and number of the erupted permanent teeth were radiographically assessed in the left mandibular quadrant. Dental panoramic tomographs of 50 OI patients, naïve to bisphosphonates, and of 50 healthy individuals of the same age were used as controls. The dental development was statistically significantly accelerated in the OI group naïve to bisphosphonates showing median advancement of dental age by 0.63years from chronological age and median increase in the number of erupted teeth by 0.31 as compared to Finnish norms. Bisphosphonate-treated OI patients displayed, however, age-appropriate dental development. The OI patients not treated with bisphosphonates also showed statistically significantly faster resorption of the deciduous teeth than the treated ones, and displayed an altered interrelationship between the resorption stage of an individual primary tooth and the developmental stage of the succedaneous permanent tooth, unlike the OI patients treated with bisphosphonate. No correlation between either cumulative bisphosphonate dose or between treatment length and any measured component of the dental development was found. To conclude, OI itself was found to lead to advanced dental development. Bisphosphonate treatment had a delaying effect in all the three aspects studied, resulting in a rate of dental development indistinguishable from normal.

Skull base abnormalities in osteogenesis imperfecta: a cephalometric evaluation of 54 patients and 108 control volunteers.

OBJECT: Osteogenesis imperfecta (OI), which usually results from mutations in type I collagen genes, causes bone fragility and deformities. The head is often abnormally shaped, and changes in skull base anatomy in the form of basilar impression and basilar invagination have been reported. The authors analyzed the skull base anatomy on standardized lateral cephalograms from 54 patients with OI (Types I, III, and IV) and 108 control volunteers. They were surprised to find that the previously used diagnostic measures for basilar abnormality in patients with OI were exceeded in 6.5 to 7.4% of the controls, and hence needed to be reevaluated. METHODS: The authors calculated the distance from the odontoid process to four reference lines, including a novel one, in the controls. The normal mean distances were exceeded by more than two standard deviations (SDs) in 28.3 to 35.2%, and by more than three SDs in 13.2 to 16.6% of the patients with OI. The latter figures reliably reflect the prevalence of basilar impression. As a sign of basilar invagination the odontoid process protruded into the foramen magnum or reached the foramen magnum level in 22.2% of the patients with OI, whereas none of the controls showed this feature. Platybasia (an anterior cranial base angle > 146 degrees) was present in 11.1% of the patients but in none of the controls. CONCLUSIONS: Platybasia, basilar impression, and basilar invagination were often coexpressed, but each was also present as an isolated abnormality. These three abnormalities and wormian bones were predominantly found in OI Types III and IV as well as in patients exhibiting dentinal abnormality.

Application of segmented dental panoramic tomography among children: positive effect of continuing education in radiation protection.

OBJECTIVES:: Dental panoramic tomography is the most frequent examination among 7-12-year olds, according to the Radiation Safety and Nuclear Authority of Finland. At those ages, dental panoramic tomographs (DPTs) are mostly obtained for orthodontic reasons. Children's dose reduction by trimming the field size to the area of interest is important because of their high radiosensitivity. Yet, the majority of DPTs in this age group are still taken by using an adult programme and never by using a segmented programme. The purpose of the present study was to raise the awareness of dental staff with respect to children's radiation safety, to increase the application of segmented and child DPT programmes by further educating the whole dental team and to evaluate the outcome of the educational intervention. METHODS:: A five-step intervention programme, focusing on DPT field limitation possibilities, was carried out in community-based dental care as a part of mandatory continuing education in radiation protection. Application of segmented and child DPT programmes was thereafter prospectively followed up during a 1-year period and compared with our similar data from 2010 using a logistic regression analysis. RESULTS:: Application of the child programme increased by 9% and the segmented programme by 2%, reaching statistical significance (odds ratios 1.68; 95% confidence interval 1.23-2.30; p-value < 0.001). The number of repeated exposures remained at an acceptable level. The segmented DPTs were most frequently taken from the maxillary lateral incisor-canine area. CONCLUSIONS:: The educational intervention resulted in improvement of radiological practice in respect to radiation safety of children during dental panoramic tomography. Segmented and child DPT programmes can be applied successfully in dental practice for children.