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The aim of this observational cross-sectional one-centre study was to assess whether the previously described national orthodontic treatment practises and international recommendations are implemented in a public health care centre in Finland. We also assessed early treatment practices and appliances used.The study group comprised 801 children born in 2011 and 2012 residing in the Riihimäki health centre catchment area in Finland, representing 80% of the age cohort. The patient records were examined for data on orthodontic treatment, timing of treatment, appliances used, and occlusal traits.The children had been examined by four orthodontist specialists and two orthodontic postgraduate students. Mean age at occlusal examination had been 9 years. Of the children, 212 (26%) were undergoing or had undergone orthodontic treatment. An additional 4.4% were scheduled for treatment. The proportion of children deemed to need treatment was significantly different between the different orthodontists. The most frequently used appliances were quad-helix (30%), eruption guidance appliance (20%), head gear (14%), fixed appliances (10%), protraction facemask (10%), and passive mandibular lingual arch (6%).Nearly one-third of children aged less than 12 years in the health centre were currently or had been in orthodontic treatment. Approximately half had received treatment with either quad-helix or eruption guidance appliance.

Publisher Copyright: © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Acta Odontologica Scandinavica Society. Objective: The global COVID-19 pandemic has led to an increase in remote teaching and online assessment in higher education. The examination performance of undergraduate students of dentistry was evaluated to assess any possible association between the altered learning environment and learners’ performance. Materials and methods: Using administrative data from the University of Helsinki, the examination performance during the years 2018 and 2019 was compared with that of 2020. Results: In 16 out of 22 courses (73%) taught remotely during the pandemic, a statistically significant difference (p

Introduction: The aim of the study was to compare the effects of a 30 µg/day vs 10 µg/day vitamin D supplementation, given during the two first years of life, on oral health at the age of six to seven 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 chi-square 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. Trial registration: ClinicalTrials.gov (NCT04302987)

This cross-sectional study compared tooth and dental arch dimensions of individuals with Osteogenesis imperfecta (OI) and healthy controls.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.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.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.

Objectives To assess the quality and stability of orthodontic treatment outcome relative to the initial malocclusion. Material and methods The study was performed in one public health care clinic in Finland. Study subjects comprised 51 orthodontic patients (age range 12.7-18.7 years). Pre-treatment medical records and lateral skull radiographs were analysed for malocclusion type. The main reasons for orthodontic treatment were mandibular retrognathia, Class II distal bite, deep bite and crowding. At the end of a retention phase (Examination 1), the quality of treatment outcome was assessed using the occlusal morphology and function index (OMFI) and patients were asked about treatment satisfaction. Stability of occlusal traits and patient satisfaction were re-evaluated after a two-year follow-up (Examination 2). Occlusal characteristics descriptive statistics were performed. Results At Examination 1, all six morphological criteria for acceptability were fulfilled by 76% and all functional criteria by 82% of the patients. All OMFI criteria were met by 67% of the patients. At Examination 2, 68% of the patients fulfilled all morphological and 82% all functional criteria of acceptability. At Examination 2, all the OMFI criteria were still met by 64% of the patients and 92% expressed satisfaction with own occlusion. The main reasons for unacceptability were deficiencies in canine relationship and overbite, in addition to functional protrusion interferences. Conclusions In the evaluated health care clinic, patient satisfaction and the quality of treatment outcome were high. However, deep bite showed a tendency for relapse.

BackgroundObstructive sleep apnea (OSA) is prevalent in individuals with Osteogenesis imperfecta (OI). To date, no study has investigated treatment of OSA in adult individuals with OI using positive airway pressure (PAP). This observational pilot study examined the adherence of adults with OI to treatment of OSA with PAP therapy, and the evolution of self-experienced sleepiness and depression symptoms before and after treatment.MethodsWe included 20 patients, with a mean age of 51 years, who represented varying severity of OI and displayed an apnea and hypopnea index ≥ 5 /sleeping hour as recorded by an overnight polysomnography. PAP therapy was proposed to all patients. Epworth Sleepiness Scale (ESS) questionnaire to evaluate daytime sleepiness, and a validated self-rating depression questionnaire to identify possible depression, were completed prior to PAP therapy and repeated after a minimum of one year. The datasets supporting the conclusions of this article are included within the article.ResultsFrom the 20 patients, 15 initiated PAP therapy, and two patients later interrupted it. The mean PAP follow-up period was 1230 days. At baseline, an abnormally high ESS score was reported by 29% of the respondents, and an abnormally high number of symptoms suggesting depression by 29%. Follow-up questionnaires were completed by 60% of the patients, of whom 83% were adherent to PAP treatment. ESS score and depression symptoms did not decrease significantly with PAP therapy.ConclusionsPatients with OI accepted well PAP therapy and remained compliant. Sleepiness and depression persisted unaltered despite good PAP adherence. These unexpectedly poor improvements in symptoms by PAP therapy may be due to subjective depression symptoms and the complexity of factors underlying persisting sleepiness in OI. Further research is needed to confirm this novel finding.

Summary Background Success of orthodontic removable appliance treatment relies on patient compliance. The aim of this quantitative and qualitative study was to explore the compliance and self-reported experience of adolescents in orthodontic treatment with headgear activator (HGA) or twin-block (TB) appliance. Materials/methods The study group comprised 52 adolescents with a mean age of 12.6 (±1.3) years at the start of the treatment. The patients were treated at a free-of-charge public dental clinic. Participants were randomly allocated to two equal groups to be treated with either HGA or TB. Patient compliance was evaluated as appliance wear time and subjective experience. Appliance wear time was recorded with Theramon® microchip, and the self-reported subjective experience using a questionnaire. Results In total, 30 patients completed the treatment during the follow-up period. HGA was worn on average 7 hours per day and TB 9 hours per day by those patients, who successfully completed the treatment. During a mean observation period of 13 months (range 7–23 months), the mean actual wear time was 43 per cent less than the advised 12 or 18 hours per day in the whole patient group, and 55 per cent in those patients, who completed the treatment. Compliance level was unrelated to the appliance type. Limitations Study assessed a relatively small number of patients. Conclusions/implications Adolescent patients wear HGA and TB less than advised. Individual variation in treatment adherence is considerable. Thereby, microelectronic wear-time documentation can be a cost-effective mean of identifying non-compliance.

Background Patients with Osteogenesis imperfecta (OI) suffer from increased bone fracture tendency generally caused by a mutation in genes coding for type I collagen. OI is also characterized by numerous co-morbidities, and recent data from questionnaire studies suggest that these may include increased risk for sleep apnea, a finding that lacks clinical evidence from cohort studies. In this cross-sectional study, 25 adults with OI underwent clinical otorhinolaryngology examination as well as overnight polysomnography to address the question. The participants were aged between 19 and 77 years, and ten of them had mild clinical OI phenotype, seven had a moderately severe phenotype, and eight had a severe phenotype. Results We found obstructive sleep apnea (apnea hypopnea index ≥5/h) in as many as 52% of the OI patients in the cohort. Unexpectedly, however, no correlation was present between sleep apnea and daytime sleepiness, experienced bodily pain, severity of OI, Mallampati score, or neck circumference. Conclusions Seeing that the usual predictors showed no association with occurrence of sleep apnea, we conclude that obstructive sleep apnea may easily be left as an undetected disorder in individuals with OI. Recurrent nocturnal hypoxia due to episodes of apneas can even affect bone metabolism, thereby further aggravating bone fragility in patients with OI.

OBJECT Cranial base pathology is a serious complication of osteogenesis imperfecta (OI). Our aim was to analyze whether bisphosphonate treatment, used to improve bone strength, could also prevent the development of craniocervical junction pathology (basilar impression, basilar invagination, or platybasia) in children with OI. METHODS In this single-center retrospective study the authors analyzed the skull base morphology from lateral skull radiographs and midsagittal MR images (total of 94 images), obtained between the ages of 0 and 25 years in 39 bisphosphonate-treated OI patients. The results were compared with age-matched normative values and with findings in 70 OI patients who were not treated with bisphosphonates. In addition to cross-sectional data, longitudinal data were available from 22 patients with an average follow-up period of 7.6 years. The patients, who had OI types I, III, IV, VI, and VII, had been treated with zoledronic acid, pamidronate, or risedronate for 3.2 years on average. RESULTS Altogether 33% of the 39 bisphosphonate-treated patients had at least 1 cranial base anomaly, platybasia being the most prevalent diagnosis (28%). Logistic regression analysis suggested a higher risk of basilar impression or invagination in patients with severe OI (OR 22.04) and/or older age at initiation of bisphosphonate treatment (OR 1.45), whereas a decreased risk was associated with longer duration of treatment (OR 0.28). No significant associations between age, height, or cumulative bisphosphonate dose and the risk for cranial base anomaly were detected. In longitudinal evaluation, Kaplan-Meier curves suggested delayed development of cranial base pathology in patients treated with bisphosphonates but the differences from the untreated group were not statistically significant. CONCLUSIONS These findings indicate that cranial base pathology may develop despite bisphosphonate treatment. Early initiation of bisphosphonate treatment may delay development of craniocervical junction pathology. Careful followup of cranial base morphology is warranted, particularly in patients with severe OI.

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, naive 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 naive 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.

Habitat fragmentation is a process involving splitting of continuous habitats into smaller, and more isolated habitat patches. To assess the effects of small-scale habitat patchiness and isolation without the confounding effect of habitat loss on benthic macrofauna, two field experiments were conducted in the Archipelago Sea, SW Finland. Using artificial seagrass units (ASUs) we contrasted continuous patches (“C”) with fragmented patches (“F”) of the same combined area as the continuous patches. The fragmentation treatment involved two isolation distances (0.5 and 3.0 m) between the ASUs (“F 0.5”) and (“F 3.0”). This design was repeated in two consecutive experiments where the patch area was 0.25 and 0.0625 m2, respectively. Mobile epifauna were allowed to colonize patches for 12 days in both experiments. In both experiments, the total epifaunal density was significantly higher in the “F 0.5” treatment than in the “C” treatment, and the three dominant taxa showed positive or neutral responses to the habitat configuration. No fragmentation effect on the number of species was detected in either of the experiments, but fragmentation had a negative effect on the epifaunal diversity (Shannon’s H′) in the experiment with the largest patch area. Epifaunal diversity was significantly lower in “F 3.0” treatment than in “C” or “F 0.5” treatments in the first experiment, indicating stronger effect of isolation instead of fragmentation per se. Edge effects were indirectly tested by comparing epifaunal densities with patch edge:area ratios. The results suggest that edge effects may have a more important role than patch size for the total densities of epifaunal taxa, and that small, isolated patches have equal or higher habitat value compared to larger fragments.

Cranial base abnormalities are an important complication of osteogenesis imperfecta (OI), a hereditary bone fragility disorder that in most patients is caused by mutations affecting collagen type I. To elucidate which clinical characteristics are associated with the occurrence of cranial base abnormalities in OI, we compared cephalometric results of 187 OI patients (median age 12.0 years, range 3.4 to 47 years; 96 female) with those of 191 healthy subjects and related findings to clinical descriptors of the disease. Overall, 41 patients (22%) had at least one unambiguously abnormal skull base measure. Multivariate logistic regression analysis in patients with OI types I, III, and IV (n = 169) revealed that height Z-score [odds ratio (OR) = 0.53, 95% confidence interval (CI) 0.43–0.66, p

The interaction of eutrophication and predation in structuring seagrass Zostera marina L. ecosystems was assessed in a field experiment in three regions along an estuarine salinity gradient, from southern Finland to the Skagerrak area of the Swedish west coast. All regions are considered to be affected by eutrophication and overfishing but differ in the abundance of intermediate predators (e.g., small fish, shrimp, and crabs), mesograzers, and the biomass of epiphytic algae. Using transplanted Zostera (eelgrass), nutrient levels and intermediate predator abundance were manipulated in a full-factorial cage experiment. On the Swedish west coast, where ambient densities of mesograzers are very low, epiphytic algae responded strongly to nutrient enrichment, resulting in significantly reduced growth of eelgrass. At the Baltic sites however, where ambient densities of mesograzers are high, no significant growth of epiphytic algae was detected, and only grazer biomass responded to nutrient enrichment. Predation from small fish, shrimp, and crabs decreased the biomass of mesograzers by . 98% on the Swedish west coast, but natural predators had no significant effect on mesograzers biomass at the Baltic sites. Predation and nutrient enrichment interacted to affect the growth of eelgrass by controlling the biomass of mesograzers and nuisance algae. The differing effect of nutrient enrichment and grazing in the three regions may therefore be a result of the prevailing low and high predation pressure on mesograzers in Zostera. This absence or presence of predation may derive from interregional changes in trophic interactions, possibly caused by a combination of eutrophication and overfishing.

Background Joint hypermobility is a common clinical characteristic of patients with Osteogenesis imperfecta (OI), a disorder with serious comorbidities of scoliosis and cranial base anomalies. This study aimed at evaluating how prevalent joint hypermobility is in paediatric OI patients, and to find out whether it serves as a potential predictive marker of the different spinal complications; scoliosis and craniovertebral anomalies (basilar impression and basilar invagination). Methods In this cross-sectional one-center study we analysed retrospectively clinical patient records and radiographs of 47 OI patients, aged 1–19 years, some of whom were treated with bisphosphonates. Presence of joint hypermobility, scoliosis, and craniovertebral anomalies was recorded and possible connections between the phenomena were explored with correlation analysis. Results Joint hypermobility was found in 70% of the patients. Scoliosis and cranial base anomalies had developed in 26%. The presence of spinal complications was independent of the bisphosphonate treatment status and joint hypermobility. Conclusions Scoliosis and craniovertebral anomalies are strongly associated in paediatric OI patients. Joint hypermobility that is much more common appears, however, to be a poor predictor. Electronic supplementary material The online version of this article (doi:10.1186/1471-2474-15-428) contains supplementary material, which is available to authorized users.

Cranial base and craniocervical junction anatomy can be evaluated from CT and MR scans, and lateral skull radiographs. Cranial base anatomy changes during growth, as the form of the anatomic structures and their relative positions alter. In disorders of compromised bone quality, abnormal changes in the craniocervical junction can lead to pathological conditions with possibly life-threatening neurological complications. In this investigation these issues have first been addressed by making skull base measurements of healthy growing individuals to determine the age-specific normative values used to evaluate cranial base structures. These normative values were then employed in the following analysis of growing patients suffering from osteogenesis imperfecta (OI), a disorder of bone fragility due to abnormal collagen composition. In healthy individuals cranial base measurements, young children demonstrated significantly different results from those of older growing individuals and adults. Thus studies on patients younger than 9 years should include age-appropriate controls. Significant individual variation in skull base measurements during growth may appear, as revealed by longitudinal observation. The observed wide ranges, and the fact that the position of the odontoid process in relation to skull base structures may individually display alternating up- and downward movements, are important to consider when conducting follow-up examinations. Nevertheless, a notable deviation from the documented normal values is suggestive of pathological development in the craniocervical junction. When comparing the age-specific normal values, skull base abnormalities were found to be present in approximately one fifth of OI patients; platybasia was the most frequent finding. Patients with haploinsufficiency mutations (which lead to a relatively mild phenotype) were less likely to have skull base abnormalities than patients with helical glycine substitutions. However, the strongest predictor of skull base abnormality was not the type of collagen mutation underlying OI but the clinical severity of the disorder, as expressed by the height Z-score. No evidence was found for a protective effect of bisphosphonate treatment, nor for the progression of craniocervical junction pathology with age. Based on this normative data and the observations made in patients with OI, age-appropriate screening limits for skull base pathology are proposed here, in addition to a recommendation for timing of radiological screening in patients with OI. Kallonpohjan ja kaularangan välisen liitoksen anatomiaa voidaan tarkastella magneetti- ja tietokonetomografiakuvista, sekä kallosta sivusuunnassa otetuista röntgenkuvista. Kallonpohjan ja kaularangan rakenteiden muoto, ja niiden väliset suhteet muuttuvat kasvun myötä. Sellaisissa tautitiloissa, joissa esiintyy luukudoksen poikkeavuutta, kallonpohjan ja kaularangan suhde voi muuttua siten, että syntyy henkeä uhkaava ydinjatkoksen puristustila. Tutkimuksessa tarkasteltiin ensin terveiden lasten kallon ja kaularangan välisen liitoksen mittasuhteita kasvun aikana. Näin muodostettiin viitearvot, joihin luuston haurautta aiheuttavaa osteogenesis imperfectaa (OI) sairastavien lasten vastaavia arvoja voitiin verrata. Terveiden lasten kohdalla havaittiin, että kallonpohjan ja kaularangan välisten mittasuhteiden kasvun aikaiset muutokset vaihtelivat huomattavasti eri yksilöillä ja että alle kouluikäisten mitta-arvot poikkesivat merkitsevästi vanhempien lasten ja aikuisten vastaavista arvoista. Tulosten perusteella suositellaankin, että alle 9-vuotiaiden lapsipotilaiden kallokuvia tulkittaessa tulisi käyttää iänmukaisia viitearvoja. Huomattava poikkeama viitearvoista on aihe potilaan jatkotutkimuksille mahdollisen patologisen tilan kehittymisen arvioimiseksi. Työssä havaittiin jokin kallonpohjan anomalia noin viidesosalla kasvuikäisistä OI-potilaista. Platybasia (eli kallonpohjan litistyminen) oli yleisin anomalia. Niillä potilailla, joilla OI:ta aiheuttava kollageenivirhe aiheutuu toisen alleelin toimimattomuudesta ja ilmiasuna on lievä oireyhtymämuoto, oli pienempi riski kallonpohjan anomalioihin kuin niillä potilailla, joilla oireyhtymä aiheutuu glysiinin korvautumisesta toisella aminohapolla johtaen vaikeaan oireyhtymän ilmiasuun. Potilaan suhteellinen pituus oireyhtymän vaikeusasteen ilmentäjänä oli merkittävin kallonpohjan anomalian kehittymistä ennustava tekijä. Bisfosfonaattilääkityksen ei havaittu estävän anomalioiden syntyä. Lääkitsemättömillä potilailla todettujen kallonpohjan anomalioiden ei havaittu vaikeutuvan iän myötä. Tutkimuksen pohjalta laadittiin kliiniseen käyttöön lasten viitearvojen lisäksi ehdotus toimintamalliksi OI:aa sairastavien lasten kallonpohjan radiologisten seulontatutkimusten ajoituksesta.

Pathology in the craniocervical junction is a serious complication of osteogenesis imperfecta (OI). Our aim was to analyze the prevalence and natural course of craniocervical junction anomalies in patients with OI during growth. In a one-center retrospective study, we analyzed lateral skull radiographs and midsagittal magnetic resonance images of 76 patients with either type I, III, or IV OI. The material included longitudinal series of 31 patients. In total, 150 patient images taken at ages 0 to 39 years were analyzed and compared with age-matched control data. Craniocervical anomalies were observed in 37% of patients and in all OI types studied. Of the three types of anomalies, basilar invagination was seen in 13%, basilar impression in 15%, and platybasia in 29% of the patients. From those with an abnormal finding, 44% displayed more than one type of anomaly. At a group level, we found no evidence of progression of craniocervical junction pathology with age. We provide longitudinal and cross-sectional data on craniocervical junction dimensions in growing patients with OI and, based on those, suggest a radiological management strategy for diagnosis of cranial base pathology. A higher risk of having any of the pathological conditions was associated with a lower height Z-score. Careful follow-up of cranial base anomalies particularly in subjects with OI and severe growth failure is warranted.

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. 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. 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. 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.

Structured Abstract Authors – Arponen H, Elf H, Evalahti M, Waltimo-Siren J Objective – To explore the reliability of identification of anatomic landmarks on lateral skull radiographs of young unaffected individuals that has conventionally been used to diagnose pathologic relationships in the craniovertebral junction. Material and Methods – From the Helsinki longitudinal growth study, 20 randomly selected lateral radiographs were analyzed and re-analyzed by two examiners. Both located seven cephalometric landmarks based on which five measurements were calculated. The differences of results were compared. With similar method three radiographs were analysed by 11 examiners and results were compared. Results – Some anatomic landmarks were easier to locate than others on lateral skull radiographs leading to differences in measurements based on them. We found the magnitude of the difference to be dependent on the landmark serving as reference. Inter- and intra-examiner errors were of similar magnitude, although intra-examiner error declined in the repeated landmark identification. Variation in a single landmark location had in general little effect on the measurement value. Conclusion – Variations in landmark location lead to differences in numeric evaluation of the anatomic relationships in the skull base area. These differences were, however, shown to have little clinical significance. Hence, the documented methods are applicable for screening of basilar pathology.