Cone-Beam Computed Tomography of Osteogenesis Imperfecta Types III and IV: Three-Dimensional Evaluation of Craniofacial Features and Upper Airways

Orthodontic Management in Pediatric Patients with Rare Diseases: Case Reports

Background: The orthodontic management of pediatric patients with rare diseases, such as Ectodermal Dysplasia (ED) and Osteogenesis Imperfecta (OI), requires complex protocols due to dental anomalies in both the number and structure of teeth. These conditions necessitate a departure from traditional orthodontic approaches, as skeletal anchoring is often required because of these anomalies. Case Presentation: A patient with ED, characterized by hypodontia and malformed teeth, presented with insufficient natural teeth for anchorage. This challenge was addressed using a Maxillary Skeletal Expander (MSE) with miniscrews. Cone-beam computed tomography (CBCT) and cephalometric radiographs were used to assess bone density, which guided the creation of a customized hybrid device. A second patient with OI, a condition causing fragile bones, had malformed teeth and a high risk of fractures. Skeletal anchoring with MSE and miniscrews was chosen to avoid damaging brittle bones. The fragile nature of the patient's bones required careful planning and close monitoring throughout the treatment process. Both patients were treated at the UOC of Pediatric Dentistry, Sapienza University of Rome, using MSE with miniscrews. Pre- and post-treatment imaging (CBCT and cephalometric radiographs) were used to evaluate bone quality and monitor progress. Skeletal anchoring successfully addressed the unique challenges in both cases, achieving outcomes comparable to those in unaffected patients. Discsussions: despite limited bone volume, MSE successfully achieved maxillary arch expansion and improved occlusion. Post-treatment radiographs showed successful maxillary expansion and alignment without complications. Conclusions: This case series highlighted the effectiveness of MSE with miniscrews in treating patients with rare diseases. It advances orthodontic management by offering reliable solutions for complex cases involving dental anomalies and compromised bone structures.

Skeletal and Non-skeletal Phenotypes in Children with Osteogenesis Imperfecta

Although fractures are the defining characteristic of osteogenesis imperfecta (OI), the disorder affects many tissues. Here we discuss three facets of the OI phenotype, skeletal growth and development, skeletal muscle weakness and the dental and craniofacial characteristics. Short stature is almost universal in the more severe forms of OI and is probably caused by a combination of direct effects of the underlying genetic defect on growth plates and indirect effects of fractures, bone deformities and scoliosis. Recent studies have developed OI type-specific growth curves, which allow determining whether a given child with OI grows as expected for OI type. Impaired muscle function is an important OI-related phenotype in severe OI. Muscles may be directly affected in OI by collagen type I abnormalities in muscle connective tissue and in the muscle-tendon unit. Indirect effects like bone deformities and lack of physical activity may also contribute to low muscle mass and function. Dental and craniofacial abnormalities are also very common in severe OI and include abnormal tooth structure (dentinogenesis imperfecta), malocclusion, and deformities in the bones of the face and the skull. It is hoped that future treatment approaches will address these OI-related phenotypes.

A standard set of outcome measures for the comprehensive assessment of oral health and occlusion in individuals with osteogenesis imperfecta

BACKGROUND

Osteogenesis imperfecta (OI) is a group of inherited connective tissue disorders of varying severity characterized by bone fragility. The primary objective of this international multidisciplinary collaboration initiative was to reach a consensus for a standardized set of clinician and patient-reported outcome measures, as well as associated measuring instruments for dental care of individuals with OI, based on the aspects considered important by both experts and patients. This project is a subsequent to the Key4OI project initiated by the Care4BrittleBones foundation which aims to develop a standard set of outcome measures covering a large domain of factors affecting quality of life for people with OI. An international team of experts comprising orthodontists, pediatric dentists, oral and maxillofacial surgeons, and prosthetic dentists used a modified Delphi consensus process to select clinician-reported outcome measures (CROMs) and patient-reported outcome measures (PROMs) to evaluate oral health in individuals with OI. Important domains were identified through a literature review and by professional expertise (both CROMs and PROMs). In three focus groups of individuals with OI, important and relevant issues regarding dental health were identified. The input from the focus groups was used as the basis for the final set of outcome measures: the selected issues were attributed to relevant CROMs and, when appropriate, matched with validated questionnaires to establish the final PROMs which represented best the specific oral health-related concerns of individuals with OI.

RESULTS

Consensus was reached on selected CROMs and PROMs for a standard set of outcome measures and measuring instruments of oral health in individuals with OI.

CONCLUSIONS

Our project resulted in consensus statements for standardization oral health PROMs and CROMs in individuals with OI. This outcome set can improve the standard of care by incorporating recommendations of professionals involved in dental care of individuals with OI. Further, it can facilitate research and international research co-operation. In addition, the significant contribution of the focus groups highlights the relevance of dental and oral health-related problems of individuals with OI.

Cranio-cervical abnormalities in moderate-to-severe osteogenesis imperfecta - Genotypic and phenotypic determinants

INTRODUCTION

Cranio-cervical anomalies are significant complications of osteogenesis imperfecta (OI), a rare bone fragility disorder that is usually caused by mutations in collagen type I encoding genes.

OBJECTIVE

To assess cranio-cervical anomalies and associated clinical findings in patients with moderate-to-severe OI using 3D cone beam computed tomography (CBCT) scans.

METHODS

Cross-sectional analysis of CBCT scans in 52 individuals with OI (age 10-37 years; 32 females) and 40 healthy controls (age 10-32 years; 26 females). Individuals with a diagnosis of OI type III (severe, n = 11), type IV (moderate, n = 33) and non-collagen OI (n = 8) were recruited through the Brittle Bone Disorders Consortium. Controls were recruited through the orthodontic clinic of the University of Missouri-Kansas City (UMKC).

RESULTS

OI and control groups were similar in mean age (OI: 18.4 [SD: 7.2] years, controls: 18.1 [SD: 6.3] years). The cranial base angle was increased in the OI group (OI: mean 148.6° [SD: 19.3], controls: mean 130.4° [SD: 5.7], P = .001), indicating a flatter cranial base. Protrusion of the odontoid process into the foramen magnum (n = 7, 14%) and abnormally located odontoid process (n = 19, 37%) were observed in the OI group but not in controls. Low stature, expressed as height z-score (P = .01), presence of DI (P = .04) and being male (P = .04) were strong predictors of platybasia, whereas height z-score (P = .049) alone was found as positive predictor for basilar impression as per the Chamberlain measurement.

CONCLUSION

The severity of the phenotype in OI, as expressed by the height z-score, correlates with the severity of cranial base anomalies such as platybasia and basilar impression in moderate-to-severe OI. Screening for cranial base anomalies is advisable in individuals with moderate-to-severe OI, with special regards to the individuals with a shorter stature and DI.

Emerging Landscape of Osteogenesis Imperfecta Pathogenesis and Therapeutic Approaches

Osteogenesis imperfecta (OI) is an uncommon genetic disorder characterized by shortness of stature, hearing loss, poor bone mass, recurrent fractures, and skeletal abnormalities. Pathogenic variations have been found in over 20 distinct genes that are involved in the pathophysiology of OI, contributing to the disorder's clinical and genetic variability. Although medications, surgical procedures, and other interventions can partially alleviate certain symptoms, there is still no known cure for OI. In this Review, we provide a comprehensive overview of genetic pathogenesis, existing treatment modalities, and new developments in biotechnologies such as gene editing, stem cell reprogramming, functional differentiation, and transplantation for potential future OI therapy.

Craniofacial and dental phenotype of two girls with osteogenesis imperfecta due to mutations in CRTAP

Mutations in CRTAP lead to an extremely rare form of recessive osteogenesis imperfecta (OI). CRTAP deficient mice have a brachycephalic skull, fusion of facial bones, midface retrusion and class III dental malocclusion, but in humans, the craniofacial and dental phenotype has not been reported in detail. Here, we describe craniofacial and dental findings in two 11-year-old girls with biallelic CRTAP mutations. Patient 1 has a homozygous c.472-1021C>G variant in CRTAP intron 1 and a moderately severe OI phenotype. The variant is known to create a cryptic splice site, leading to a frameshift and nonsense-mediated RNA decay. Patient 1 started intravenous bisphosphonate treatment at 2 years of age. At age 11 years, height Z-score was +0.6. She had a short and wide face, concave profile and class III malocclusion, with a prognathic mandible and an antero-posterior crossbite. A panoramic radiograph showed a poor angulation of the second upper right premolar, and no dentinogenesis imperfecta or dental agenesis. Cone-beam computed tomography confirmed these findings and did not reveal any other abnormalities. Patient 2 has a homozygous CRTAP deletion of two amino acids (c.804_809del, p.Glu269_Val270del) and a severe OI phenotype. As previously established, the variant leads to instability of CRTAP protein. Intravenous bisphosphonate treatment was started at the age of 15 months. At 11 years of age her height Z-score was -9.7. She had a long and narrow face and convex profile, maxillary retrusion leading to a class III malocclusion, an edge-to-edge overjet and lateral open bite. Panoramic radiographs showed no dental abnormalities. Cone-beam computed tomography showed occipital bossing, platybasia and wormian bones. In these two girls with CRTAP mutations, the severity of the skeletal phenotype was mirrored in the severity of the craniofacial phenotype. Class III malocclusion and antero-posterior crossbite were a common trait, while dental agenesis or dentinogenesis imperfecta were not detected.

Craniofacial morphology in adults with osteogenesis imperfecta – a cross‐sectional study

OBJECTIVES

The aim of this study was to compare the craniofacial and neurocranial morphology of adults with osteogenesis imperfecta (OI) with controls and to elucidate whether osseous origin impacts on morphological deviations in OI.

MATERIALS AND METHODS

Fifty-four adults (mean age 45.8) with OI type I, 14 adults (mean age 42.6) with OI types III/IV and 49 adult controls (mean age 41.0) were included. All participants had European ethnicity. Cranial morphology was assessed by 2D-cephalometry. Comparison between groups was made by multiple regression analyses.

RESULTS

Comparison between OI groups and controls: (1) Dimension of the maxilla and mandible, respectively was reduced (P < .01), and in relation to the posterior cranial base, the maxilla was retro-positioned (P < .001), and the mandible was prognathic (P < .001). (2) The anterior face height was reduced (P < .04), and in OI types III/IV only, the maxilla was posteriorly inclined (P < .001). (3) Anterior cranial base (P < .001) and the dimension sella-frontale (P < .02) were short. (4) The sagittal dimension of the posterior cranial fossa was increased (P < .01), and the vertical dimension was reduced (P < .01).

CONCLUSIONS

Adults with OI had a hypoplastic, retro-positioned and posteriorly inclined maxilla, a hypoplastic and forward-positioned mandible, and a reduced anterior face height. Deviations were seen in morphology of the posterior cranial fossa. The impact of OI on cranial morphology was generally more evident in OI type III/IV than in OI type I. OI impacts on osseous cranial structures irrespective of bony origin being intramembranous or endochondral.

Widespread disturbance in extracellular matrix collagen biomarker responses to teriparatide therapy in osteogenesis imperfecta

Osteogenesis imperfecta (OI), a heritable disorder caused by abnormalities in synthesis or processing of type I collagen, is characterized by skeletal fragility. Type I collagen interacts with multiple components of the extracellular matrix (ECM) including other collagens types. Thus, alterations in structure or quantity may broadly affect ECM homeostasis. In fact, while OI is clinically categorized by severity of bone disease, patients can also present with extra-skeletal manifestations, including the pulmonary, muscle and cardiovascular systems. Parathyroid hormone (PTH) is a regulator of skeletal homeostasis but the receptor for PTH/PTH1R is expressed in a variety of other tissues. Given interactions between type I collagen with other collagens in the ECM and the potential for PTH action on tissues beyond the skeleton, we explored whether serum levels of non-type I collagens are altered in response to teriparatide (human parathyroid hormone 1-34). We measured biomarkers of collagens II, III, IV, V, and VI in serum from individuals with type I and types III/IV OI in response to an 18 month course of teriparatide or placebo. These results were compared to similar biomarker measures in postmenopausal (PM) women without OI treated with teriparatide. In type I OI, teriparatide therapy increased concentrations of biomarkers of collagens II, III, IV, V, and VI. In individuals with types III/IV OI these biomarker changes in response to teriparatide were blunted, as we previously reported with collagen I biomarkers during teriparatide therapy. In contrast to OI, in PM women there were no effects of teriparatide on the collagen biomarkers we assessed (II, V, and VI). These findings suggest that in OI teriparatide therapy has abnormal effects on the homeostasis of many ECM collagens likely derived from skeletal as well as extra-skeletal tissues.

New 3D Cone Beam CT Imaging Parameters to Assist the Dentist in Treating Patients with Osteogenesis Imperfecta

(1) Background: The aim of the work is to identify some imaging parameters in osteogenesis imperfecta to assist the dentist in the diagnosis, planning, and orthodontic treatment of Osteogenesis Imperfecta (OI) using 3D cone beam Computed Tomography (CBCT) and the Double Energy X-ray Absorptiometry (DEXA) technique. (2) Methods: 14 patients (9 males and 5 females; aged mean ± SD 15 ± 1.5) with a clinical-radiological diagnosis of OI were analyzed and divided into mild and moderate to severe forms. The patients' samples were compared with a control group of 14 patients (8 males and 6 females; aged mean ± SD 15 ± 1.7), free from osteoporotic pathologies. (3) Results: The statistical analysis allowed us to collect four datasets: in the first dataset (C1 sick population vs. C1 healthy population), the t-test showed a p-value < 0.0001; in the second dataset (C2 sick population vs. C2 healthy population), the t-test showed a p-value < 0.0001; in the third dataset (parameter X of the sick population vs. parameter X of the healthy population), the t-test showed a p-value < 0.0001; in the fourth dataset the bone mineralometry (BMD) value detected by the DEXA technique compared to the C2 value of the OI affected population only) the Welch-Satterthwaite test showed a p-value < 0.0001. (4) Conclusions: The research has produced specific imaging parameters that assist the dentist in making diagnostic decisions in OI patients. This study shows that patients with OI have a characteristic chin-bearing symphysis, thinned, and narrowed towards the center, configuring it with a constant "hourglass" appearance, not reported so far in the literature by any author.

Osteogenesis imperfecta: an update on clinical features and therapies

Osteogenesis imperfecta (OI) is an inherited skeletal dysplasia characterized by bone fragility and skeletal deformities. While the majority of cases are associated with pathogenic variants in COL1A1 and COL1A2, the genes encoding type I collagen, up to 25% of cases are associated with other genes that function within the collagen biosynthesis pathway or are involved in osteoblast differentiation and bone mineralization. Clinically, OI is heterogeneous in features and variable in severity. In addition to the skeletal findings, it can affect multiple systems including dental and craniofacial abnormalities, muscle weakness, hearing loss, respiratory and cardiovascular complications. A multi-disciplinary approach to care is recommended to address not only the fractures, reduced mobility, growth and bone pain but also other extra-skeletal manifestations. While bisphosphonates remain the mainstay of treatment in OI, new strategies are being explored, such as sclerostin inhibitory antibodies and TGF beta inhibition, to address not only the low bone mineral density but also the inherent bone fragility. Studies in animal models have expanded the understanding of pathomechanisms of OI and, along with ongoing clinical trials, will allow to develop better therapeutic approaches for these patients.