Dental perspectives in fibrous dysplasia and McCune-Albright syndrome

Metabolic Bone Diseases Affecting Tooth Eruption: A Narrative Review

Tooth eruption is an essential process for the development of the oral and maxillofacial system. Several inherited and acquired diseases might affect this tightly regulated process, resulting in premature, delayed, or even failed tooth eruption. The purpose of this article is to review the literature and the clinical parameters of metabolic bone diseases that affect tooth eruption. It examines the physiological aspects of tooth eruption and the pathophysiological changes induced by metabolic bone diseases, including changes in bone metabolism, density, and structure. The search strategy for this review included an electronic search in PubMed, Google Scholar, Medline, Scopus, and the Cochrane Library using the following keywords: "metabolic bone diseases", "tooth eruption", "delayed tooth eruption", and each reported disease in combination with "tooth eruption disorders", covering publications up to March 2024 and limited to English-language sources. Understanding the influence of metabolic bone diseases on tooth eruption is crucial for managing both dental and skeletal manifestations associated with these disorders. This review suggests that a multidisciplinary approach to treatment may significantly improve oral outcomes for patients suffering from such conditions. Clinicians should be aware of the specific dental abnormalities that may arise and consider comprehensive evaluations and individualized treatment plans. These findings underscore the need for further research into targeted therapies that address these abnormalities.

Effects of HMGB1/TLR4 on secretion IL-10 and VEGF in human jaw bone-marrow mesenchymal stem cells

OBJECTIVE

We aimed to investigate the regulatory effects of HMGB1/TLR4 signaling pathway on the expression of IL-10 and VEGF in human bone marrow mesenchymal stem cells.

METHODOLOGY

Human JBMSCs were isolated and cultured. Then, HMGB1 was added into the JBMSCs culture medium, and the protein and mRNA expression levels of IL-10 and VEGF were assessed. Moreover, cells were pretreated with a specific TLR4 inhibitor (TAK-242), and the expression changes of IL-10 and VEGF were compared.

RESULTS

Compared with the control group, exposure to HMGB1 in human JBMSCs up-regulated TLR4, IL-10, and VEGF secretion at both protein and mRNA levels (P<0. 05). In addition, the increased expression of IL-10 and VEGF could be restrained in TAK-242 group compared with the HMGB1 group (P<0.05).

CONCLUSIONS

The results indicated that HMGB1 activate TLR4 signaling pathway in Human JBMSCs, which plays a regulatory role in cytokines expression.

GNAS locus: bone related diseases and mouse models

GNASis a complex locus characterized by multiple transcripts and an imprinting effect. It orchestrates a variety of physiological processes via numerous signaling pathways. Human diseases associated with the GNAS gene encompass fibrous dysplasia (FD), Albright's Hereditary Osteodystrophy (AHO), parathyroid hormone(PTH) resistance, and Progressive Osseous Heteroplasia (POH), among others. To facilitate the study of the GNAS locus and its associated diseases, researchers have developed a range of mouse models. In this review, we will systematically explore the GNAS locus, its related signaling pathways, the bone diseases associated with it, and the mouse models pertinent to these bone diseases.

Lesion Expansion in Gnathic Fibrous Dysplasia: Natural History, Indicators of Progression, and Response to Bisphosphonates

Fibrous dysplasia (FD) is characterized by expansile fibro-osseous lesions that may occur in association with endocrinopathies as part of McCune-Albright syndrome (MAS). Craniofacial FD is a significant source of morbidity and most commonly involves the gnathic bones. There is a critical need to understand the natural history and risk factors for gnathic FD progression to develop preventative trials and identify candidates for intervention. The purpose of this study was to characterize gnathic FD lesion expansion and to identify risk factors associated with lesion growth. Patients with gnathic FD and serial CT imaging were evaluated. Volumetric analyses of CT scans were performed using MIM Encore software. Generalized mixed model analysis was used to account for intra-subject correlation, with FD lesion volume as the dependent variable. In addition to age, effects of MAS-associated endocrinopathies, sex, disease severity, and bisphosphonate treatment were evaluated. A total of 104 total lesions in 52 patients were characterized longitudinally. Median age at initial scan was 8.8 years (range 3.4-18.8), and median age at final scan was 16.8 years (range 6.9-33.4 years). The median number of scans per subject was 4 (range 2-14). FD lesion volume increased with age (2.50 cm3 /yr, 95% confidence interval [CI] 1.95-3.04, p < 0.001). However, lesion expansion rate decreased over time (-0.05 cm3 /yr, 95% CI -0.07 to 0.04, p < 0.001). Mandibular lesions tended to expand at a greater rate than maxillary lesions (p < 0.001). Growth hormone excess was associated with accelerated expansion rate (p = 0.002). Other MAS-associated endocrinopathies, pubertal status, sex, weight, lesion density, disease severity, and bisphosphonate treatment were not associated with lesion volume or expansion. Gnathic FD lesion expansion is most rapid in younger children and declines as patients approach adulthood. The availability of quantitative natural history data will guide clinicians in identifying patients who are candidates for medical and surgical interventions and clinical trials for preventative therapies. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Craniofacial Fibrous Dysplasia: Clinical and Therapeutic Implications

PURPOSE OF REVIEW

This study aims to review diagnosis, potential complications, and clinical management in craniofacial fibrous dysplasia.

RECENT FINDINGS

Fibrous dysplasia (FD) is a rare mosaic disorder in which normal bone and marrow are replaced with expansile fibro-osseous lesions. Disease presents along a broad spectrum and may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). The craniofacial skeleton is one of the most commonly impacted areas in FD, and its functional and anatomical complexities create unique challenges for diagnosis and management. This review summarizes current approaches to diagnosis and management in FD/MAS, with emphasis on the clinical and therapeutic implications for the craniofacial skeleton.

Comprehensive management of malocclusion in maxillary fibrous dysplasia: A case report

BACKGROUND

Fibrous dysplasia (FD) is a developmental hamartomatous bone disease characterized by a blend of fibrous and osseous entities. Though rarely malignant, the tumor can vary from being small and asymptomatic, to a fairly large sized lesion, progressing gradually, compromising occlusion and facial esthetics. Treatment approach depends on the stage of skeletal maturity. It primarily involves surgical management for stabilizing the disease process. Post-surgical comprehensive dental treatment is necessary for restoring form and function of the jaws and teeth. This article describes comprehensive orthodontic management of severe malocclusion in a surgically operated case of FD maxilla.

CASE SUMMARY

A 19-year female presented with a chief complaint of excessive gingival display when smiling. Dental history included swelling of gums around the upper right front teeth, diagnosed at the age of 15 as FD of the right anterior maxillary segment and treated with surgical recontouring of the dysplastic bone. The clinical and radiological examinations showed adequate post-surgical healing. The surgically treated dysplastic area presented with right canting of the maxillary anterior occlusal plane. The maxillary teeth were torqued palatally, with the root of the right maxillary canine exposed clinically. We discuss sequential management of the associated malocclusion with comprehensive fixed orthodontics, along with special precautions taken to prevent reactivation of the quiescent and healed lesion.

CONCLUSION

The adequate healing of fibro-dysplastic bone post-surgery must be allowed before initiating orthodontic tooth movement in the dysplastic bone. Periodic follow-ups are needed to monitor stability of occlusion and any relapse of the lesion.

A CREB1-miR-181a-5p loop regulates the pathophysiologic features of bone marrow stromal cells in fibrous dysplasia of bone

BACKGROUND

Fibrous dysplasia (FD) is a bone marrow stromal cell (BMSC) disease caused by activating mutations of guanine nucleotide-binding protein alpha-stimulating activity polypeptide (GNAS) and is characterized by increased proliferative activity and disrupted osteogenesis of BMSCs. However, the molecular mechanisms regulating the pathophysiologic features of BMSCs in FD remain unknown. This study aimed to identify and verify the roles of the CREB1-miR-181a-5p regulatory loop in FD pathophysiology.

METHODS

MicroRNA (miRNA) sequencing analysis was used to identify the possible miRNAs implicated in FD. The proliferation, apoptosis, and osteogenic differentiation of BMSCs, as well as the osteoclast-induced phenotype, were measured and compared after exogenous miR-181a-5p transfection into FD BMSCs or miR-181a-5p inhibitor transfection into normal BMSCs. Chromatin immunoprecipitation and luciferase reporter assays were performed to verify the interactions between CREB1 and miR-181a-5p and their effects on the FD pathological phenotype.

RESULTS

Compared to normal BMSCs, FD BMSCs showed decreased miR-181a-5p levels and exhibited increased proliferative activity, decreased apoptotic capacity, and impaired osteogenesis. FD BMSCs also showed a stronger osteoclast activation effect. miR-181a-5p overexpression reversed the pathophysiologic features of FD BMSCs, whereas miR-181a-5p suppression induced an FD-like phenotype in normal BMSCs. Mechanistically, miR-181a-5p was the downstream target of CREB1, and CREB1 was posttranscriptionally regulated by miR-181a-5p.

CONCLUSIONS

Our study identifies that the interaction loop between CREB1 and miR-181a-5p plays a crucial role in regulating the pathophysiologic features of FD BMSCs. MiR-181a-5p may be a potential therapeutic target for the treatment of FD.

Radiographic Diagnosis of Systemic Diseases Manifested in Jaws

Radiographic changes of the oral and maxillofacial hard tissues can be an indication of an underlying systemic disease. In this article, the range of individual disease entities that have both systemic and dental manifestations are reviewed. Images for many conditions are provided to illustrate the radiographic changes. A summary of the most common jaw affected, radiographic and pathognomonic findings, and management aspects is listed in a table format within this article for quick reference.

Craniofacial Fibrous Dysplasia Involvements of Mccune-Albright Syndrome: A Review with an Additional Case

BACKGROUND

McCune-Albright Syndrome (MAS) is a genetic disorder with a triad of endocrine diseases, café-au-lait macules and fibrous dysplasias. Craniofacial fibrous dysplasia is a term that is used to describe the fibrous dysplasia, which was localized at the craniofacial skeleton and is common in MAS patients.

OBJECTIVE

The objective of this review is to determine the involvement frequency of cranial and facial bones in patients with MAS and CFD.

METHODS

Articles in PubMed was searched with the following details "(mccune[Title/Abstract] OR albright[Title/Abstract]) OR ("craniofacial fibrous dysplasia"[MeSH Terms] OR ("craniofacial"[ All Fields] AND "fibrous"[All Fields] AND "dysplasia"[All Fields]) OR "craniofacial fibrous dysplasia"[All Fields])". The articles in which the authors did not state the involved bones or did not add any radiographic images were excluded from the study.

RESULTS

26 cases in 25 articles met the inclusion criteria. Among the 26 cases and our case, sphenoid and frontal bones were involved in 17 cases, parietal and occipital bones were involved in 15 cases, mandible and ethmoid bone were involved in 14 cases, maxilla-zygoma-temporal and palate was involved in 13, 11, 6 and 3 cases, respectively. Palate was involved in cases where maxilla was also involved. Our case was the only case that was evaluated with CBCT.

CONCLUSION

Routine follow-ups are important since new CFDs can occur in different cranial or facial bones. 2D imaging techniques may not be able to demonstrate early CFDs; thus, an advanced imaging technique should be used after MAS diagnosis.

The Implications of Endocrinology in Orthodontics – Literature Review

Endocrinopathies have a variety of orofacial presentations which span from dental malocclusion to facial disfigurement. These characteristics depend on the nature and severity of the condition. An orthodontist should understand the body’s physiological processes to be able to timely determine the optimum intervention and plan treatment stages accordingly in compromised individuals. Communication between the two specialties should be well coordinated and should help facilitate quality health care to the patient. This review was aimed to impart the basic knowledge and the pivotal guidelines for orthodontic management in these conditions. Systemic conditions require multidisciplinary management and the dental team should aim to provide quality oral health care to enhance the overall quality of life and the orthodontist plays a vital role in helping patients achieve physical and psychological health.

Craniofacial fibrous dysplasia associated with McCune-Albright syndrome: challenges in diagnosis and treatment: case reports

Background

McCune-Albright syndrome (MAS) is a rare multisystem disorder that classically was defined by the triad of polyostotic fibrous dysplasia of bone, café-au-lait skin pigmentation, and precocious puberty. It is a condition that has a gradual onset, slow growth rate and remain painless throughout. The clinical phenotype of MAS is highly variable and no definite treatment is available.

Case presentation

This article describes two cases, a 10-year-old girl and an 11-year-old boy, both with MAS comprising deforming craniofacial FD. Challenges related to diagnosis and management included late reporting with big lesions, involvement of multiple craniofacial bones, mutilating surgeries and ultimately high degree of morbidity.

Conclusion

Delayed diagnosis and management of MAS results in devastating physical disabilities and severe morbidity after treatment.

Mandibular 3-dimensional finite element analysis for a patient with an aggressive form of craniofacial fibrous dysplasia

The longitudinal change in mandibular volume and configuration was quantitatively evaluated in a patient with craniofacial fibrous dysplasia (FD). The influence of mechanical stress on the enlargement that is characteristic of FD was verified via finite element analysis (FEA). The patient was a 38-year-old man diagnosed with craniofacial FD in the mandible. He underwent surgical reduction of FD, but the lesion continued to grow and caused facial asymmetry and masticatory disturbance because of missing teeth. An occlusal overlay removable partial denture was constructed for his lower jaw. Computed tomography (CT) images were acquired 4 times in 10 years, and 3-dimensional (3-D) models were reconstructed from these data. The 3-D models were analyzed volumetrically and morphologically and used for FEA. The FD lesion in the mandible enlarged nonuniformly and had site specificity. From the results of FEA, it is suggested that compression stress induced by the occlusal force through the denture may have influenced the direction of enlargement in FD.

An Analysis of Clinical and Histopathologic Features of Fibrous Dysplasia of the Jaws: A Series of 40 Cases and Review of Literature

Fibrous dysplasia (FD) is a rare condition commonly involving the jaws. While FD has a typical clinical and histological presentation, considerable variation exists. Moreover, overlap of features with other disorders is possible. This study serves to characterize the features of a large case series of FD of the jaws. With IRB approval, the University of Florida Oral Pathology Biopsy Service archive was retrospectively searched from 1994 to 2015 for cases of FD. Epidemiological data, location, duration, clinical and radiographic appearance, clinical impression and exact microscopic diagnosis were recorded. The average age was 37.3 years (range 7-87 years) with majority of cases in females (67.5%). The most common ethnicity was Caucasian. Maxillary location was predominant (59%), followed by mandible (38%) and multiple locations (3%). Expansion was reported in 78% of cases. Radiographically, most cases exhibited ground glass opacity, however some presented with a mottled or mixed radiopaque/radiolucent appearance. Histologically, a wide variation in terms of stromal cellularity, presence of osteoblastic rimming, and presence of calcified material mimicking cemento-osseous dysplasia was observed. Clinicians and pathologists should be cognizant of the significant variability in clinical, histopathologic, and radiographic presentation of FD, which may pose a diagnostic challenge.

Orthodontic treatment of patient with maxillofacial fibrous dysplasia: A case report

Fibrous dysplasia is a benign skeletal disorder in which the normal bone and marrow are replaced by fibrous tissue and haphazardly distributed woven bone. The aim of this case report is to discuss the orthodontic treatment of a 13-year-old patient with fibrous dysplasia in the left maxilla. The patient had rotated maxillary second premolars, moderate crowding in both maxillary and mandibular arches with low maxillary frenal attachment. Orthodontic treatment was done with full fixed appliance and extraction of maxillary and mandibular third molars. Maxillary frenectomy and free gingival graft in mandibular anterior region were performed by a periodontist. The oral and maxillofacial surgery team monitored fibrous dysplasia in the left maxilla on a yearly interval. There is very limited information about orthodontic management of patients with craniofacial fibrous dysplasia. This case report discusses the orthodontic treatment and the importance of interdisciplinary approach in the management of patient with maxillofacial fibrous dysplasia.

Key words:Orthodontic treatment, fibrous dysplasia, maxillofacial fibrous dysplasia, case report.

[Dental-craniofacial manifestation and treatment of rare diseases in China]

Rare diseases are genetic, chronic, and incurable disorders with relatively low prevalence. Thus, diagnosis and management strategies for such diseases are currently limited. This situation is exacerbated by insufficient medical sources for these diseases. The National Health and Health Committee of China recently first provided a clear definition of 121 rare diseases in the Chinese population. In this study, we summarize several dental-craniofacial manifestations associated with some rare diseases to provide a reference for dentists and oral maxillofacial surgeons aiming at fast-tracking diagnosis for the management of these rare diseases.

Dental-craniofacial manifestation and treatment of rare diseases

Rare diseases are usually genetic, chronic and incurable disorders with a relatively low incidence. Developments in the diagnosis and management of rare diseases have been relatively slow due to a lack of sufficient profit motivation and market to attract research by companies. However, due to the attention of government and society as well as economic development, rare diseases have been gradually become an increasing concern. As several dental-craniofacial manifestations are associated with rare diseases, we summarize them in this study to help dentists and oral maxillofacial surgeons provide an early diagnosis and subsequent management for patients with these rare diseases.

Surgical Treatment of Fibroosseous Lesion in Young Patient with Reduced Mouth Opening

Fibrous dysplasia is a benign fibroosseous disorder that can affect the maxillary bones, causing aesthetic deformity and functional impairment. This article reports the case of a 13-year-old male patient at the time of diagnosis. The patient showed increased facial volume with relevant asymmetry, having reported the onset of the condition 12 months before. Upon examination, the patient presented an 8-mm mouth opening and an acute inflammatory process associated with tooth 37 pericoronal hood. Upon imaging exam, exuberant bone growth in the left mandibular ramus area of ground glass aspect was observed. After incisional biopsy, fibrous dysplasia was diagnosed and sequentially treated with osteoplasty and coronoid process removal. The patient evolved to a 43-mm mouth opening and favorable aesthetics without recurrence in a 3-year follow-up period. In this case, coronoidectomy and bone plasty proved to be effective, returning aesthetics and function. The patient is supposed to be followed up in the long term.

HDAC8, A Potential Therapeutic Target, Regulates Proliferation and Differentiation of Bone Marrow Stromal Cells in Fibrous Dysplasia

Fibrous dysplasia (FD) is a disease of postnatal skeletal stem cells caused by activating mutations of guanine nucleotide-binding protein alpha-stimulating activity polypeptide (GNAS). FD is characterized by high proliferation and osteogenesis disorder of bone marrow stromal cells (BMSCs), resulting in bone pain, deformities, and fractures. The cAMP-CREB pathway, which is activated by GNAS mutations, is known to be closely associated with the occurrence of FD. However, so far there is no available targeted therapeutic strategy for FD, as a critical issue that remains largely unknown is how this pathway is involved in FD. Our previous study revealed that histone deacetylase 8 (HDAC8) inhibited the osteogenic differentiation of BMSCs via epigenetic regulation. Here, compared with normal BMSCs, FD BMSCs exhibited significantly high proliferation and weak osteogenic capacity in response to HDAC8 upregulation and tumor protein 53 (TP53) downregulation. Moreover, inhibition of cAMP reduced HDAC8 expression, increased TP53 expression and resulted in the improvement of FD phenotype. Importantly, HDAC8 inhibition prevented cAMP-induced cell phenotype and promoted osteogenesis in nude mice that were implanted with FD BMSCs. Mechanistically, HDAC8 was identified as a transcriptional target gene of CREB1 and its transcription was directly activated by CREB1 in FD BMSCs. In summary, our study reveals that HDAC8 associates with FD phenotype and demonstrates the mechanisms regulated by cAMP-CREB1-HDAC8 pathway. These results provide insights into the molecular regulation of FD pathogenesis, and offer novel clues that small molecule inhibitors targeting HDAC8 are promising clinical treatment for FD. Stem Cells Translational Medicine 2019;8:148&14.

Fibrous dysplasia imitating malignancy

Fibrous dysplasia is a benign bone disease, presenting as monostotic or polyostotic lesions, or as part of a syndrome (McCune-Albright/Mazabraud). Its clinical course shows a variegated picture and the progression of its growth is unpredictable. In the workup of 39 fibrous dysplasia cases in the cranio-facial area, four cases presented fast growth tendencies, of which two patients with McCune-Albright syndrome showed malignant-like rapid growth. This local aggressive form is extremely rare, and the concept of this issue has not been clearly defined. With regard to the speed of growth a volumetric-time analysis in one of our cases demonstrated a 74 days tumor doubling rate with an exponential growth curve. According to the literature the aggressive form presented extra-cranially mainly at an adult age, whereas its appearance in our cranio-facial patient collective was much younger. Distinguishing nonmalignant and malignant aggressive forms is difficult and highly inconsistent in the literature. We therefore implemented a quantitative growth measure analysis to define aggressive forms based on progression and speed of growth and impartial of type of FD, localization or functional incapacity. Due to our study findings and literature review we state a prevalence of an aggressive form might be possibly about 5 %.

Differential diagnosis and clinical management of periapical radiopaque/hyperdense jaw lesions

Great attention has been given to the study of radiolucent periapical lesions to avert possible misdiagnosis of apical periodontitis associated with certain radiolucent non-endodontic lesions. However, there are a significant number of radiopaque lesions found in the periapical region, which could be equally relevant to endodontic practice. The diagnosis and management of these radiopaque/hyperdense lesions could be challenging to the endodontist. These bone alterations could be neoplastic, dysplastic or of metabolic origin. In the context of the more widespread use of cone-beam CT, a detailed review of radiopaque inflammatory and non-inflammatory lesions is timely and may aid clinicians perform a differential diagnosis of these lesions. Distinguishing between inflammatory and non-inflammatory lesions simplifies diagnosis and consequently aids in choosing the correct therapeutic regimen. This review discusses the literature regarding the clinical, radiographic, histological and management aspects of radiopaque/hyperdense lesions, and illustrates the differential diagnoses of these lesions.

The bone regenerative capacity of canine mesenchymal stem cells is regulated by site-specific multilineage differentiation

OBJECTIVES

Mesenchymal stem cells (MSCs) offer a promising therapy in dentistry because of their multipotent properties. Selecting donor MSCs is crucial because Beagle dogs (canines) commonly used in preclinical studies have shown variable outcomes, and it is unclear whether canine MSCs (cMSCs) are skeletal site specific. This study tested whether jaw and long bone cMSCs have disparate in vitro and in vivo multilineage differentiation capabilities.

STUDY DESIGN

Primary cMSCs were isolated from the mandible (M-cMSCs) and femur (F-cMSCs) of four healthy Beagle dogs. The femur served as the non-oral control. Clonogenic and proliferative abilities were assessed. In vitro osteogenic, chondrogenic, adipogenic, and neural multilineage differentiation were correlated with in vivo bone regeneration and potential for clinical applications.

RESULTS

M-cMSCs displayed two-fold increase in clonogenic and proliferative capacities relative to F-cMSCs (P = .006). M-cMSCs in vitro osteogenesis based on alkaline phosphatase (P = .04), bone sialoprotein (P = .05), and osteocalcin (P = .03), as well as adipogenesis (P = .007) and chondrogenesis (P = .009), were relatively higher and correlated with enhanced M-cMSC bone regenerative capacity. Neural expression markers, nestin and βIII-tubulin, were not significantly different.

CONCLUSIONS

The enhanced differentiation and bone regenerative capacity of mandible MSCs may make them favorable donor graft materials for site-specific jaw bone regeneration.

Fibrous dysplasia of bone: craniofacial and dental implications

Fibrous dysplasia (FD) is a rare bone disease caused by postzygotic somatic activating mutations in the GNAS gene, which lead to constitutive activation of adenylyl cyclase and elevated levels of cyclic AMP, which act on downstream signaling pathways and cause normal bone to be replaced with fibrous tissue and abnormal (woven) bone. The bone disease may occur in one bone (monostotic), multiple bones (polyostotic), or in combination with hyperfunctioning endocrinopathies and hyperpigmented skin lesions (in the setting of McCune-Albright Syndrome). FD is common in the craniofacial skeleton, causing significant dysmorphic features, bone pain, and dental anomalies. This review summarizes the pathophysiology, clinical findings, and treatment of FD, with an emphasis on the craniofacial and oral manifestations of the disease.

Fibrous Dysplasia and Medication-Related Osteonecrosis of the Jaw

PURPOSE

Osteonecrosis of the jaw (ONJ) is an established side effect of intravenous bisphosphonates and other antiresorptive medications. Although bisphosphonates are frequently prescribed for patients with the skeletal disorder fibrous dysplasia (FD), there are no reports of ONJ in this population. This has led some to conclude that patients with FD are at low risk for the development of bisphosphonate-related ONJ.

PATIENTS AND METHODS

Patients were evaluated as part of a longstanding FD natural history study at the National Institutes of Health.

RESULTS

Of 76 patients with FD who were treated with bisphosphonates, 4 developed ONJ (5.4%). Three patients developed ONJ in areas of FD-affected bone and 1 in an area of normal bone. All 4 patients had features known to be associated with ONJ in the general population, including long-term high-dose intravenous bisphosphonate treatment, periodontal and endodontic infections, and dentoalveolar surgical procedures.

CONCLUSIONS

These cases establish ONJ as a potential complication of bisphosphonate treatment in patients with FD. The presence of established risk factors for ONJ in this group of patients with FD suggests that high-risk patients could be identified before the development of ONJ. Clinicians should use caution in prescribing bisphosphonates to patients with FD and should do so only for established indications.

A case report: retigabine induced oral mucosal dyspigmentation of the hard palate

Background

Dyspigmentation of the oral mucosa has a multitude of aetiological causes. Retigabine, a new antiepileptic drug, has the potential side effect of inducing a blue/purple pigmentation of the oral mucosa in addition to the skin, lips, nails and retina of the eyes. This article presents a unique case of dyspigmentation present in the oral mucosa of the hard palate which has previously been unreported in the dental literature.

Case presentation

A 70 year old white male presented to a secondary care oral surgery department with an unusual asymptomatic pigmented lesion present in the hard palate of the oral cavity. The pigmentation was remarkable for its distinct blue/purple colouration which was associated with a similar discolouration of the nail beds of the hands. This is believed to be a side effect of the anti-epileptic medication retigabine.

Conclusion

The dental profession and wider healthcare community should be made fully aware of the potential side effect of oral dyspigmentation associated with the novel anti-epileptic medication retigabine. Enhanced knowledge of the causative role of retigabine in dyspigementation of the oral mucosa will allow the practitioner to make an appropriate diagnosis. As far the authors are aware this is reaction is unreported in the dental literature and should be disseminated to the wider oral health professional’s community.

A case of craniofacial fibrous dysplasia associated with McCune-Albright syndrome lost to follow-up

McCune-Albright syndrome is a rare fibro-osseous syndrome characterised by a classic triad of fibrous dysplasia (FD), café-au-lait macules and various underlying endocrinopathies. This case report describes how a patient was rediagnosed by a general dental practitioner following attendance for a routine dental examination. The patient had been previously diagnosed with the condition 28 years earlier but no follow-up or monitoring of her condition had taken place. As a result, she was found to have several undiagnosed and untreated complications of the disease including FD of the mandible, optic neuropathy and potential thyroid involvement.

Maxillofacial fibro-osseous lesions

During the last decade much has changed in our understanding of fibro-osseous lesions (FOLs) of the jaws with regards to their imaging, their nomenclature and classification, and their potential impact on the overall health of the patient. The changes in nomenclature, classification, and the FOLs' potential association with important syndromes are discussed with the assistance of a flowchart. The lesions, fibrous dysplasia (FD), ossifying fibroma (OF), and osseous dysplasia (OD), though with similar histopathology, have very different clinical and radiological presentations, behaviour, and treatment outcomes. FD of the jaw, which though becoming inactive, does not involute and therefore requires life-long review to monitor for occasional reactivation. OF is completely removed surgically as it has a propensity to recur. No treatment is generally required for an OD unless it is infected or displays expansion. Lesions outside the jaws associated with FOLs of the jaws are identified. Radiology remains central to the diagnosis of FOLs of the jaw, because the pathologist is still not able to distinguish between them. The advent of cone-beam computed tomography (CBCT) with its better radiation dose reduction, accessibility, and spatial resolution has transformed imaging of FOLs. Their presentations on CBCT and the clinical indications for its use are discussed.

Rare bone diseases and their dental, oral, and craniofacial manifestations

Hereditary diseases affecting the skeleton are heterogeneous in etiology and severity. Though many of these conditions are individually rare, the total number of people affected is great. These disorders often include dental-oral-craniofacial (DOC) manifestations, but the combination of the rarity and lack of in-depth reporting often limit our understanding and ability to diagnose and treat affected individuals. In this review, we focus on dental, oral, and craniofacial manifestations of rare bone diseases. Discussed are defects in 4 key physiologic processes in bone/tooth formation that serve as models for the understanding of other diseases in the skeleton and DOC complex: progenitor cell differentiation (fibrous dysplasia), extracellular matrix production (osteogenesis imperfecta), mineralization (familial tumoral calcinosis/hyperostosis hyperphosphatemia syndrome, hypophosphatemic rickets, and hypophosphatasia), and bone resorption (Gorham-Stout disease). For each condition, we highlight causative mutations (when known), etiopathology in the skeleton and DOC complex, and treatments. By understanding how these 4 foci are subverted to cause disease, we aim to improve the identification of genetic, molecular, and/or biologic causes, diagnoses, and treatment of these and other rare bone conditions that may share underlying mechanisms of disease.