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Jensen ED, Smart G, Lee N, Tan J, Oliver K, Ha WN, Ranjitkar S. Prevalence and morphological features of molar-root incisor malformation in children attending a specialist paediatric dental unit. Int J Paediatr Dent 2023; 33:543-552. [PMID: 36826376 DOI: 10.1111/ipd.13061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/30/2023] [Accepted: 02/18/2023] [Indexed: 02/25/2023]
Abstract
BACKGROUND Molar-root incisor malformation (MRIM) is a rare dental anomaly featuring constricted cervical margins and tapered, narrow root and pulp morphology, often associated with severe toothache and infection. AIM The aim of this study was to determine the prevalence of MRIM in children seen in a specialist paediatric dental unit of a tertiary referral hospital and to describe the characteristics of affected individuals. DESIGN This study was an audit of children attending from November 2020 to November 2021. Radiographs were used to identify individuals with MRIM, and clinical data were collated. In addition, histology and microcomputed tomography (microCT) imaging were performed on teeth extracted from an affected individual. RESULTS The prevalence of MRIM was five cases of 1054 children examined (0.47% or 1:210). The permanent first molars were affected in all five children and the primary second molars in two children; all children had medical comorbidities and multiple exposures to general anesthesia before 4 years of age. In addition, histological and microCT analyses displayed numerous microchannels connecting the pulp chamber to the external surface of the tooth at the furcation. CONCLUSIONS Molar-root incisor malformation is an uncommon dental anomaly affecting paediatric patients with multiple comorbidities and is characterized by porosities extending from the pulp chamber to the external tooth surface, predisposing the risk of bacterial ingress from the oral cavity into the pulp chamber. Early detection may prevent atypical odontogenic facial pain and infection.
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Affiliation(s)
- Emilija D Jensen
- Department of Paediatric Dentistry, Women's and Children's Hospital, North Adelaide, South Australia, Australia
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - Gabrielle Smart
- Department of Paediatric Dentistry, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Nara Lee
- SA Pathology, Department of Anatomical Pathology, Women's and Children's Hospital, Adelaide, South Australia, Australia
| | - Jenny Tan
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - Kelly Oliver
- Department of Paediatric Dentistry, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - William N Ha
- Department of Endodontics, Sydney Dental School, University of Sydney, Sydney, New South Wales, Australia
| | - Sarbin Ranjitkar
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
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Jensen ED, Smart G, Poirier BF, Sethi S. Molar-root incisor malformation - a systematic review of case reports and case series. BMC Oral Health 2023; 23:576. [PMID: 37596569 PMCID: PMC10439578 DOI: 10.1186/s12903-023-03275-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 07/31/2023] [Indexed: 08/20/2023] Open
Abstract
OBJECTIVES Molar-root incisor malformation (MRIM) is a seldom reported condition characterised by disturbances in root development of first permanent molars. This systematic review aimed to collate the clinical characteristics of individuals diagnosed with MRIM. MATERIALS AND METHODS A systematic search strategy using PubMed, Embase, Web of Science, and SCOPUS databases was performed through to March 2023. Inclusion criteria were case reports or case series including a diagnosis consistent with MRIM. Critical appraisal for all included studies utilised the Joanna Briggs Institute (JBI) critical appraisal checklist for case reports and case series and collation of clinical characteristics was performed in JBI System for the Unified Management, Assessment and Review of Information program. RESULTS The search identified 157 studies from which 35 satisfied the inclusion criteria. After full-text review, a total of 23 papers described the MRIM dental anomaly and were included in this paper. A total of 130 reported cases were retrieved, with age ranging 3-32 years, and males affected 1.16:1 females. Presence of neurological conditions, premature birth history, medication, and surgery within first years of life were synthesised and described. CONCLUSIONS The aetiology of MRIM is yet to be determined but epigenetic changes from significant medical history in the first years of life are likely to influence the development of this root malformation. First permanent molars were most commonly affected, but clinicians should be aware that permanent central incisors, primary teeth and other permanent teeth may also be affected.
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Affiliation(s)
- Emilija D Jensen
- Department of Paediatric Dentistry, Women's and Children's Hospital, North Adelaide, South Australia, Australia.
- Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia.
| | - Gabrielle Smart
- Department of Paediatric Dentistry, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Brianna F Poirier
- Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Sneha Sethi
- Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia
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Charisi C, Kodonas K, Keklikoglou K, Arhakis A, Arapostathis KA, Kotsanos N. Morphological, histological, and chemical analysis of first permanent molars with molar incisor malformation. Eur Arch Paediatr Dent 2022; 23:601-608. [PMID: 35759186 DOI: 10.1007/s40368-022-00723-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/02/2022] [Indexed: 10/17/2022]
Abstract
PURPOSE Molar incisor malformation (MIM) is a dental anomaly rendering first permanent molar pulps inflamed/necrotic at a young age. It often affects permanent incisors, primary second molars and less frequently other teeth. The purpose of this study was to investigate the anatomy and histology of MIM in seeking insight into its pathogenesis. METHODS Five MIM first permanent molars were examined with micro-computed tomography (micro-CT) for 3D morphology, with scanning electron microscopy for microanatomy, with energy-dispersive X-ray spectrometer (EDS) for chemical composition and for histology with optical microscopy. Composition differences were statistically determined using one-way ANOVA. RESULTS Micro-CT confirmed dentin abnormalities in the middle and cervical third of the crown in the form of the radiodense 'cervical mineralized diaphragm' (CMD). This was peripherally intertwined with enamel fjords and projections severely disrupting the integrity of pulp chamber and its continuity with root canals. EDS showed increased Ca in CMD compared to dentin. The histological examination revealed anomalous osteodentin-like hard tissue with denticles in the CMD. CONCLUSION An interconnection of anomalous cervical enamel with crown CMD dentin preceded to the severe pulp chamber and root dysplasias in MIM molar teeth.
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Affiliation(s)
- C Charisi
- Department of Paediatric Dentistry, School of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece. .,, 36, El. Venizelou, 57008, Thessaloniki, Greece.
| | - K Kodonas
- Department of Endodontics, School of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - K Keklikoglou
- Biology Department, University of Crete, 70013, Heraklion, Crete, Greece.,Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research (HCMR), 71500, Heraklion, Crete, Greece
| | - A Arhakis
- Department of Paediatric Dentistry, School of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - K A Arapostathis
- Department of Paediatric Dentistry, School of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - N Kotsanos
- Department of Paediatric Dentistry, School of Dentistry, School of Health Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
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Song JS, Yang YM, Kim YJ, Kim JW. Management of Severely Aberrant Permanent First Molars in Molar Root-Incisor Malformation Patients: Case Series and a Guideline. CHILDREN-BASEL 2021; 8:children8100904. [PMID: 34682169 PMCID: PMC8534414 DOI: 10.3390/children8100904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/02/2021] [Accepted: 10/08/2021] [Indexed: 11/19/2022]
Abstract
Recently, a new type of dental anomaly, a molar–incisor malformation or molar root–incisor malformation (MRIM), was recognized. The disease phenotype is now relatively well characterized; however, its etiology and disease-mechanism need to be elucidated. The affected teeth do not respond well to conventional treatment because of severe malformation and an unusual root structure. In this study, we present the treatment of MRIM cases with the extraction of severely aberrant permanent first molars (PFMs) and suggest that the PFM extractions are performed when it is clear that third molars will develop. The purpose of this report was primarily to present amendments to the guidelines for the treatment of patients with MRIM.
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Affiliation(s)
- Ji-Soo Song
- Department of Pediatric Dentistry, School of Dentistry & DRI, Seoul National University, Seoul 03080, Korea; (J.-S.S.); (Y.-J.K.)
| | - Yeon-Mi Yang
- Department of Pediatric Dentistry, School of Dentistry, Chonbuk National University, Jeonju-si 54896, Korea;
| | - Young-Jae Kim
- Department of Pediatric Dentistry, School of Dentistry & DRI, Seoul National University, Seoul 03080, Korea; (J.-S.S.); (Y.-J.K.)
| | - Jung-Wook Kim
- Department of Pediatric Dentistry, School of Dentistry & DRI, Seoul National University, Seoul 03080, Korea; (J.-S.S.); (Y.-J.K.)
- Department of Molecular Genetics, School of Dentistry & DRI, Seoul National University, Seoul 03080, Korea
- Correspondence:
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MacKenzie SJ. Diagnostic Imaging in Veterinary Dental Practice. J Am Vet Med Assoc 2021; 258:369-373. [PMID: 33539205 DOI: 10.2460/javma.258.4.369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Vargo RJ, Reddy R, Da Costa WB, Mugayar LRF, Islam MN, Potluri A. Molar-incisor malformation: Eight new cases and a review of the literature. Int J Paediatr Dent 2020; 30:216-224. [PMID: 31677309 DOI: 10.1111/ipd.12592] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Molar-incisor malformation (MIM) is a recently described dental abnormality. While MIM mimics dentin dysplasia, it presents in a localized pattern. Furthermore, it is speculated that MIM is caused by significant early-life medical history. AIM The purpose of this study is to present a series of MIM cases and compare the findings with the literature. DESIGN An extensive search of all published cases of MIM in the English-language literature was conducted. Additionally, an institutional review board-approved retrospective search was performed within the University of Florida oral pathology biopsy service archives. Radiographic consultation cases were also included. Cases lacking radiographs were excluded. RESULTS Seventy-nine cases were identified in the literature, and eight cases were identified in our retrospective search. All but one case involved the permanent first molars. The average age at diagnosis was 9 years. Many patients reported significant early-life medical histories. CONCLUSIONS MIM usually affects the permanent first molars and may be linked to early-life medical conditions or interventions. Oral healthcare providers, especially paediatric dentists, should be aware of MIM to avoid misdiagnosing it as dentin dysplasia. Long-term follow-up studies with thorough medical history documentation are essential to understand the pathogenesis and aetiology and to create treatment guidelines.
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Affiliation(s)
- Richard J Vargo
- Oral and Maxillofacial Pathology Specialty Care Unit, A.T. Still University - Missouri School of Dentistry & Oral Health, St. Louis, MO, USA
| | - Rekha Reddy
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Walmir B Da Costa
- Department of Pediatric Dentistry, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Leda R F Mugayar
- Department of Pediatric Dentistry, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Mohammed N Islam
- Department of Oral and Maxillofacial Diagnostic Sciences, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Anitha Potluri
- Department of Diagnostic Sciences, University of Pittsburgh, School of Dental Medicine, Pittsburgh, PA, USA
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Abstract
Molar root-incisor malformation (MRIM) or molar-incisor malformation (MIM) is a new type of dental anomaly characterized by dysplastic roots of permanent first molars, occasionally second primary molars, and the crowns of maxillary central incisors. MRIM involving permanent first molars and second primary molars is characterized by normal crowns with short, thin, and narrow roots, whereas MRIM involving permanent maxillary central incisors exhibits constrictions of the crown in the cervical area. In the first case, we extracted the affected first permanent molars at the optimal timing to minimize space deficiencies and induce space closure. In addition, composite resin restorations were performed on the anterior central incisors. In the second case, a mandibular lingual arch was used to stabilize the affected teeth in order to mitigate discomfort by reducing rotational biting forces.
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Ng KK, Rine S, Choi E, Fiani N, Porter I, Fink L, Peralta S. Mandibular Carnassial Tooth Malformations in 6 Dogs-Micro-Computed Tomography and Histology Findings. Front Vet Sci 2019; 6:464. [PMID: 31956654 PMCID: PMC6951429 DOI: 10.3389/fvets.2019.00464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/29/2019] [Indexed: 02/04/2023] Open
Abstract
Objective: To document the clinical, radiographic, and histological characteristics of mandibular first molar teeth with developmental abnormalities previously attributed to dens invaginatus and enamel pearls in dogs. Materials and Methods: Affected mandibular first molar teeth from dogs were evaluated grossly and via intraoral radiography. Endodontically and/or periodontally compromised teeth were extracted and subjected to some combination of micro-computed tomography, histopathology, and immunohistochemistry with anti-amelogenin antibody. Results: Six dogs with developmental abnormalities of mandibular first molar teeth were identified, representing 11 affected teeth. The condition was bilateral in 5 dogs, while in 1 dog, only one mandibular first molar tooth was present. Patient weight ranged from 1.7 to 6 kg (median = 4.09 kg). On intraoral radiographs, root convergence or parallelism was noted in 6 of 11 teeth, and root dilaceration was noted in 3 of 11 teeth. Eight teeth required extraction due to periapical lucencies or periodontitis. On micro-CT, the abnormal teeth were characterized by the presence of abnormal, heterogenous hard tissue with beam attenuation characteristics midway between that of enamel and dentin. Enamel fissures were identified in 4 of 8 teeth, while ectopic radicular enamel was identified in 2 of 8 teeth. The abnormal tissue was traversed by channels measuring 20-40 μm in diameter. Channels communicated with the enamel fissures in 2/8 teeth, the furcation in 2/8 teeth and the pulp in 4/8 teeth. The abnormal tissue was frequently surrounded by disorganized dentin. Histologic features of enamel and dentin were absent from the abnormal tissue and immunohistochemistry to detect amelogenin in the abnormal tissue was negative in all samples. Conclusion: The dental abnormalities described here correspond to a previously unrecognized developmental abnormality involving the mandibular first molar teeth in dogs. The developmental origin of the abnormal tissue could not be ascertained, and further investigations are required to determine the mode of formation, origin of the abnormal tissue, and factors associated with development. These developmental abnormalities more closely resemble molar-incisor malformation, rather than dens invaginatus or enamel pearls as described in humans. The authors propose that affected mandibular first molar teeth simply be referred to as having carnassial tooth malformations.
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Affiliation(s)
- Kevin K Ng
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Stacy Rine
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Eunju Choi
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Nadine Fiani
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Ian Porter
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Lisa Fink
- Arizona Veterinary Dental Specialists, Scottsdale, AZ, United States
| | - Santiago Peralta
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
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Kim JE, Hong JK, Yi WJ, Heo MS, Lee SS, Choi SC, Huh KH. Clinico-radiologic features of molar-incisor malformation in a case series of 38 patients: A retrospective observational study. Medicine (Baltimore) 2019; 98:e17356. [PMID: 31577730 PMCID: PMC6783184 DOI: 10.1097/md.0000000000017356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Molar-incisor malformation (MIM) is a recently defined dental abnormality of molar root and incisors, and introduced as one of the causes of periapical and periodontal abscess. The purpose of this study was to investigate the clinical and radiological features of MIM, with special emphasis on various medical history. A total of 38 patients with MIM were included in this study. Radiographic features and clinical data, including medical history, chief complaint, associated complications, treatment, and prognosis, were retrospectively investigated. On radiographs, the affected molars showed short, slender, underdeveloped roots and constricted pulp chambers. All affected incisors and canines exhibited dilacerated short roots, wedge-shaped defect on the cervical part of the crown. Complications included periodontal bone loss (52.6%), endodontic lesion (50.0%), and endodontic-periodontal lesion (28.9%). The medical histories of the patients with MIM indicate that almost all (94.7%) were hospitalized due to problems during the neonatal period. MIM may cause various dental problems, such as periapical and periodontal abscess and early loss of the affected teeth. The early diagnosis of MIM on radiographs and appropriate treatment will contribute to a favorable prognosis, especially for young and adolescent patients.
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Affiliation(s)
- Jo-Eun Kim
- Department of Oral and Maxillofacial Radiology, Seoul National University Dental Hospital
| | - Joon-Ki Hong
- School of Dentistry, Seoul National University, Seoul
| | - Won-Jin Yi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Seoul National University, Seoul
| | - Min-Suk Heo
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Seoul National University, Seoul
| | - Sam-Sun Lee
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Seoul National University, Seoul
| | - Soon-Chul Choi
- Department of Oral and Maxillofacial Radiology, School of Dentistry, Seoul National University, Seoul
| | - Kyung-Hoe Huh
- Department of Oral and Maxillofacial Radiology, School of Dentistry and Dental Research Institute, Seoul National University, Republic of Korea
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Neo HLL, Watt EN, Acharya P. Molar-incisor malformation: A case report and clinical considerations. J Orthod 2019; 46:343-348. [PMID: 31544657 DOI: 10.1177/1465312519875973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Molar-incisor malformation (MIM) is a dental anomaly that has recently been presented in the literature. It features morphological root abnormalities affecting the permanent first molars, resulting in narrow, shortened or almost completely absent roots in patients who interestingly still present with clinically normal crowns. In some cases, this condition also involves the roots of the deciduous second molars in a similar manner and the maxillary central incisors may exhibit notching around the cervical region of the clinical crown. Root dysplasia of the permanent first molars compromises the long-term survival of these teeth and, in itself, presents a challenge when attempting to undertake any orthodontic treatment. This case report describes an incidental finding of a patient presenting with similar features to that of MIM, discusses the features and clinical implications of this newly discovered condition, and highlights the importance of undertaking a comprehensive radiological investigation before treatment.
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Affiliation(s)
| | - Eileen N Watt
- Orthodontic Department, Eastman Dental Institute, London, UK
| | - Priti Acharya
- Orthodontic Department, Eastman Dental Institute, London, UK
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Pavlič A, Vrecl M, Jan J, Bizjak M, Nemec A. Case report of a molar-root incisor malformation in a patient with an autoimmune lymphoproliferative syndrome. BMC Oral Health 2019; 19:49. [PMID: 30902077 PMCID: PMC6431033 DOI: 10.1186/s12903-019-0739-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 03/13/2019] [Indexed: 12/19/2022] Open
Abstract
Background Molar-root incisor malformation (MRIM) is a novel dental phenotype likely related to a patient’s past medical history. This case aimed to confirm MRIM by histological and scanning electron microscopy (SEM) examination for the first time in a patient diagnosed with autoimmune lymphoproliferative syndrome (ALPS) and to propose a possible link between ALPS and MRIM that could be attributable to abnormally proliferated bone marrow. Case presentation A 12.5-year-old boy with an extensive medical history, including diagnosis of ALPS, was examined clinically and radiologically to elucidate the reason for pain primarily originating from the area of the lower left permanent first molar tooth (PFM; tooth 36). Dental examination and radiographic survey revealed abnormal pulp cavity morphology of all four PFMs, and these were extracted, resolving the dental pain in the patient. The extracted PFMs were subjected to light microscopy, SEM evaluation and mineral density and elemental composition analyses. Histology of two PFMs revealed the presence of dentin-, bone- and cartilage-like tissues with abundant blood vessels occupying the majority of the pulp chamber. The root canals were obliterated with mineralized structures resembling pulp stones. Two different, highly mineralized abnormal tissues filling the majority of the pulp chamber revealed by SEM and confirming the diagnosis of MRIM displayed a mineral density and elemental composition similar to those of enamel and dentin, respectively. Conclusions It appears likely that in addition to the complex medical history during early childhood in the present case, extensive lymphoid infiltrates that are possible in ALPS patients can be regarded as a cofactor in the development of MRIM by exerting considerable pressure on the developing tooth bud and providing cells capable of differentiating into diverse cell types.
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Affiliation(s)
- Alenka Pavlič
- Department of Paediatric and Preventive Dentistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
| | - Milka Vrecl
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Janja Jan
- Department of Dental Diseases and Endodontics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Milan Bizjak
- Department of Materials and Metallurgy, Faculty of Natural Sciences and Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Ana Nemec
- Small Animal Clinic, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
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Malik Z, Alexiou M, Hallgrimsson B, Economides AN, Luder HU, Graf D. Bone Morphogenetic Protein 2 Coordinates Early Tooth Mineralization. J Dent Res 2018; 97:835-843. [PMID: 29489425 DOI: 10.1177/0022034518758044] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Formation of highly organized dental hard tissues is a complex process involving sequential and ordered deposition of an extracellular scaffold, followed by its mineralization. Odontoblast and ameloblast differentiation involves reciprocal and sequential epithelial-mesenchymal interactions. Similar to early tooth development, various Bmps are expressed during this process, although their functions have not been explored in detail. Here, we investigated the role of odontoblast-derived Bmp2 for tooth mineralization using Bmp2 conditional knockout mice. In developing molars, Bmp2LacZ reporter mice revealed restricted expression of Bmp2 in early polarized and functional odontoblasts while it was not expressed in mature odontoblasts. Loss of Bmp2 in neural crest cells, which includes all dental mesenchyme, caused a delay in dentin and enamel deposition. Immunohistochemistry for nestin and dentin sialoprotein (Dsp) revealed polarization defects in odontoblasts, indicative of a role for Bmp2 in odontoblast organization. Surprisingly, pSmad1/5/8, an indicator of Bmp signaling, was predominantly reduced in ameloblasts, with reduced expression of amelogenin ( Amlx), ameloblastin ( Ambn), and matrix metalloproteinase ( Mmp20). Quantitative real-time polymerase chain reaction (RT-qPCR) analysis and immunohistochemistry showed that loss of Bmp2 resulted in increased expression of the Wnt antagonists dickkopf 1 ( Dkk1) in the epithelium and sclerostin ( Sost) in mesenchyme and epithelium. Odontoblasts showed reduced Wnt signaling, which is important for odontoblast differentiation, and a strong reduction in dentin sialophosphoprotein ( Dspp) but not collagen 1 a1 ( Col1a1) expression. Mature Bmp2-deficient teeth, which were obtained by transplanting tooth germs from Bmp2-deficient embryos under a kidney capsule, showed a dentinogenesis imperfecta type II-like appearance. Micro-computed tomography and scanning electron microscopy revealed reduced dentin and enamel thickness, indistinguishable primary and secondary dentin, and deposition of ectopic osteodentin. This establishes that Bmp2 provides an early temporal, nonredundant signal for directed and organized tooth mineralization.
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Affiliation(s)
- Z Malik
- 1 School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - M Alexiou
- 1 School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - B Hallgrimsson
- 2 Department of Cell Biology and Anatomy, Faculty of Medicine, University of Calgary, AB, Canada
| | | | - H U Luder
- 4 Institute of Oral Biology, Centre for Dental Medicine, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - D Graf
- 1 School of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,5 Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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Brusevold IJ, Bie TMG, Baumgartner CS, Das R, Espelid I. Molar incisor malformation in six cases: description and diagnostic protocol. Oral Surg Oral Med Oral Pathol Oral Radiol 2017; 124:52-61. [DOI: 10.1016/j.oooo.2017.03.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 03/20/2017] [Accepted: 03/26/2017] [Indexed: 10/19/2022]
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Zschocke J, Schossig A, Bosshardt DD, Karall D, Glueckert R, Kapferer-Seebacher I. Variable expressivity of TCTEX1D2 mutations and a possible pathogenic link of molar-incisor malformation to ciliary dysfunction. Arch Oral Biol 2017; 80:222-228. [PMID: 28475963 DOI: 10.1016/j.archoralbio.2017.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/12/2017] [Accepted: 04/17/2017] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Clarification of the molecular basis of a ciliopathy associated with molar-incisor malformation in a consanguineous Turkish family. DESIGN Full dental and clinical examinations, histologic analysis, comprehensive genetic analyses including exome sequencing, ciliary function tests and transmission electron microscopy of ciliary biopsies in the surviving patient. RESULTS Two siblings had situs inversus and complex heart defects suggestive of ciliary dysfunction. The affected girl who died in utero showed severe chest abnormalities compatible with Jeune syndrome which were not present in the affected boy. Dental investigations in the boy showed typical signs of molar-incisor-malformation. Exome sequencing identified a homozygous intragenic deletion in TCTEX1D2 which is predicted to completely remove protein function. Ciliary function tests and electron microscopy showed mild irregularities of motile cilia such as compound cilia and loss of membranes. CONCLUSIONS Our findings support the suggestion that TCTEX1D2 mutations have variable expressivity and may be associated with disturbances of embryonic development caused by both, ciliary signaling and motile dysfunction. The presence of molar-incisor-malformation in the living patient raises the possibility of a pathogenetic link of this rare dental anomaly to ciliary dysfunction during tooth development at least in some individuals.
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Affiliation(s)
- Johannes Zschocke
- Division of Human Genetics, Medical University Innsbruck, Peter-Mayr-Strasse 1, 6020 Innsbruck, Austria.
| | - Anna Schossig
- Division of Human Genetics, Medical University Innsbruck, Peter-Mayr-Strasse 1, 6020 Innsbruck, Austria.
| | - Dieter D Bosshardt
- Robert K. Schenk Laboratory of Oral Histology, University of Bern, Freiburgstrasse 7, 3010 Bern, Switzerland.
| | - Daniela Karall
- Clinic for Pediatrics I, Inherited Metabolic Disorders, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria.
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria.
| | - Ines Kapferer-Seebacher
- Department of Operative and Restorative Dentistry, Medical University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria.
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15
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Yue W, Kim E. Nonsurgical Endodontic Management of a Molar-Incisor Malformation-affected Mandibular First Molar: A Case Report. J Endod 2016; 42:664-8. [DOI: 10.1016/j.joen.2015.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 10/27/2015] [Accepted: 11/02/2015] [Indexed: 11/28/2022]
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16
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Abstract
The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS) which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus, even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on root formation.
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Affiliation(s)
- Hans U Luder
- Center of Dental Medicine, Institute of Oral Biology, University of Zurich Zurich, Switzerland
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17
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Wright JT, Curran A, Kim KJ, Yang YM, Nam SH, Shin TJ, Hyun HK, Kim YJ, Lee SH, Kim JW. Molar root-incisor malformation: considerations of diverse developmental and etiologic factors. Oral Surg Oral Med Oral Pathol Oral Radiol 2015; 121:164-72. [PMID: 26682518 DOI: 10.1016/j.oooo.2015.08.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/04/2015] [Accepted: 08/07/2015] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The objective of this study was to evaluate the variation in the condition referred to as molar root-incisor malformation (MRIM) and elucidate the distribution of affected teeth. This study further aimed to identify associated environmental stressors. STUDY DESIGN Individuals were identified through retrospective review of dental radiographs and through referral to the investigators. Histologic evaluation included examination of mineralized and decalcified sections of affected first permanent molar teeth. RESULTS Thirty cases of MRIM were identified, with all having affected first permanent molars with dysplastic root formation. The primary second molars were affected in 57% of the cases, with permanent anterior teeth being involved in 40% of the cases. A variety of medical conditions were associated with MRIM, the most common being neurologic. Several affected individuals reported no significant past medical history or environmental stressors. CONCLUSIONS The etiology of MRIM remains unclear, and this unique developmental defect of the first permanent molar roots appears to occur in populations throughout the world. Clinicians identifying the MRIM phenotype should carefully evaluate the permanent incisors for associated developmental defects that could result in pulpal necrosis.
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Affiliation(s)
- John Timothy Wright
- Department of Pediatric Dentistry School of Dentistry, University of North Carolina, NC, USA
| | - Alice Curran
- Department of Diagnostic Sciences, School of Dentistry, University of North Carolina, NC, USA
| | - Kyoung-Jin Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Yeon-Mi Yang
- Department of Pediatric Dentistry, School of Dentistry, Chonbuk National University, Jeonju-si, Jeollabuk-do, Korea
| | - Soon-Hyeun Nam
- Department of Pediatric Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Teo Jeon Shin
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Hong-Keun Hyun
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Young-Jae Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Sang-Hoon Lee
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Jung-Wook Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea; Department of Molecular Genetics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
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