Numerical aberrations of permanent dentition and dystopic tooth eruption are part of the phenotype of the tumor predisposition syndrome neurofibromatosis type 1 (NF1). In these cases, surplus tooth ...germs usually develop in the alveolar processes of the jaw. This report attests to the dystopic development of a dysplastic supernumerary tooth in NF1 arising outside the jaw.
The 8-year-old male patient developed a microdont outside the bone and above the occlusal plane of the retained maxillary right second molar. The supernumerary tooth was completely embedded in oral soft tissue. Hyperplastic oral soft tissue in the molar region and microdont were excised. Specimen of the mucosa surrounding the teeth was interspersed with diffuse and plexiform neurofibroma. The retained upper right first molar emerged spontaneously within a few months after surgery. The upper right second molar did not change position.
Odontogenesis can take place within tumorous oral mucosa in NF1. Surgical removal of the tumorous mucous membrane facilitates tooth eruption in some cases.
Abstract Objective The aim of this study is to characterize the morphological and histological features of NCCLs in a group of extracted teeth using a focus variation optical microscopic technique ...that is capable of detecting minute variation in surface topography. Methods Twenty three extracted teeth containing NCCLs were collected. Histological features of the surface and longitudinal cross sections were examined using a focus variation microscope (FVM). Results The sample included 8 teeth with wedge-shaped lesions; the remaining 15 contained saucer-shaped lesions. Wedge-shaped lesions showed obliterated dentinal tubules, parallel furrows and micro-fractures in the surface; longitudinal cross sections revealed subsurface micro-fractures extending toward the pulp chamber. The surfaces of typical saucer-shaped lesions were smooth and relatively featureless. Conclusions FVM imaging shows microstructures that are consistent with simultaneous erosion and toothbrush abrasion. Saucer shaped lesions have a smooth featureless surface as well as craters and dimples that could be attributed to uneven acid attack. In wedge-shaped lesions, the presence of scratches and furrows could be attributed to mechanical forces such as tooth brush abrasion. The furrows and in-surface micro-factures of wedge shaped lesions suggest a possible role of tensile stresses but require further investigation. Clinical significance NCCLs present in two morphologies, either saucer-shaped or wedge-shaped. Erosion and toothbrush abrasion are important in both types of lesions. Tensile stresses due to occlusal loading may be important in some wedge-shaped lesions. Knowing the etiology of cervical lesions is the key for their prevention.
Dental enamel is the hardest and most mineralized tissue in extinct and extant vertebrate species and provides maximum durability that allows teeth to function as weapons and/or tools as well as for ...food processing. Enamel development and mineralization is an intricate process tightly regulated by cells of the enamel organ called ameloblasts. These heavily polarized cells form a monolayer around the developing enamel tissue and move as a single forming front in specified directions as they lay down a proteinaceous matrix that serves as a template for crystal growth. Ameloblasts maintain intercellular connections creating a semi-permeable barrier that at one end (basal/proximal) receives nutrients and ions from blood vessels, and at the opposite end (secretory/apical/distal) forms extracellular crystals within specified pH conditions. In this unique environment, ameloblasts orchestrate crystal growth via multiple cellular activities including modulating the transport of minerals and ions, pH regulation, proteolysis, and endocytosis. In many vertebrates, the bulk of the enamel tissue volume is first formed and subsequently mineralized by these same cells as they retransform their morphology and function. Cell death by apoptosis and regression are the fates of many ameloblasts following enamel maturation, and what cells remain of the enamel organ are shed during tooth eruption, or are incorporated into the tooth's epithelial attachment to the oral gingiva. In this review, we examine key aspects of dental enamel formation, from its developmental genesis to the ever-increasing wealth of data on the mechanisms mediating ionic transport, as well as the clinical outcomes resulting from abnormal ameloblast function.
Tooth wear is a commonly reported finding globally; however, many patients are unaware of having tooth wear. Identifying early signs of erosion, abrasion or attrition and determining the risk factors ...contributing to a patient's tooth wear may help to prevent further loss of enamel and dentine in the future. Appropriate prevention should be instigated, or appropriate referral made to other health professionals, when conditions such as gastroesophageal reflux or eating disorders are suspected. This paper presents the epidemiology and aetiological factors for tooth wear, as well as identifying the common clinical presentations of tooth wear. Patient perspectives on tooth wear and preventive techniques that can be utilised are also discussed.
The tooth root is an integral, functionally important part of our dentition. The formation of a functional root depends on epithelial-mesenchymal interactions and integration of the root with the jaw ...bone, blood supply and nerve innervations. The root development process therefore offers an attractive model for investigating organogenesis. Understanding how roots develop and how they can be bioengineered is also of great interest in the field of regenerative medicine. Here, we discuss recent advances in understanding the cellular and molecular mechanisms underlying tooth root formation. We review the function of cellular structure and components such as Hertwig's epithelial root sheath, cranial neural crest cells and stem cells residing in developing and adult teeth. We also highlight how complex signaling networks together with multiple transcription factors mediate tissue-tissue interactions that guide root development. Finally, we discuss the possible role of stem cells in establishing the crown-to-root transition, and provide an overview of root malformations and diseases in humans.
Each year, millions of children are injured and live with the consequences of those injuries. Through infancy and childhood, orofacial trauma caused by falls or being struck by or against objects ...occurs in children. The long‐term implications on the developing permanent teeth are little known, even when the oral region is the second most frequently injured body area in children under 6 years of age. During this period, the developing permanent teeth may be directly involved after trauma, causing mild to severe hypoplasia, displacement, damage to the tooth germ, or an extended range of morphofunctional disturbances. In some cases, the effects of oral and dental injuries caused by trauma appear later with the eruption of the permanent incisors when ectopic eruption, malalignments, and other developmental disturbances become visible. Therefore, long‐term follow up of the patient in order to diagnose and treat associated complications becomes essential. Critical points for facing the consequences of orofacial trauma on the developing dentition are to recognize the impact of orofacial trauma in young children and the dentist's role in providing anticipatory guidance to parents and health care professionals, differentiate between mild and severe disturbances affecting the developing permanent teeth after oral injuries in early childhood, recognize the importance of follow‐up controls, and recognize the importance of early referral to a pediatric dentist and orthodontist for diagnosis and treatment planning.
Under the patterning cascade model (PCM) of cusp development inspired by developmental genetic studies, it is predicted that the location and the size of later-forming cusps are more variable than ...those of earlier-forming ones. Here we assessed whether differences in the variability among cusps in total and each particular crown component (enamel-dentin junction EDJ, outer enamel surface OES, and cement-enamel junction CEJ) could be explained by the PCM, using human maxillary permanent first molars (UM1) and second deciduous molars (um2). Specimens were µCT-scanned, and 3D models of EDJ and OES were reconstructed. Based on these models, landmark-based 3D geometric morphometric analyses were conducted. Size variability in both tooth types was generally consistent with the above prediction, and the differences in size variation among cusps were smaller for the crown components completed in later stages of odontogenesis. With a few exceptions, however, the prediction was unsupported regarding shape variability, and UM1 and um2 showed different patterns. Our findings suggested that the pattern of size variability would be caused by temporal factors such as the order of cusp initiation and the duration from the beginning of mineralization to the completion of crown formation, whereas shape variability may be affected by both topographic and temporal factors.
Abstract Objectives The main purpose of this systematic review was to estimate the prevalence of dental erosion in permanent teeth of children and adolescents. Methods An electronic search was ...performed up to and including March 2014. Eligibility criteria included population-based studies in permanent teeth of children and adolescents aged 8–19-year-old reporting the prevalence or data that allowed the calculation of prevalence rates of tooth erosion. Data collection assessed information regarding geographic location, type of index used for clinical examination, sample size, year of publication, age, examined teeth and tissue exposure. The estimated prevalence of erosive wear was determined, followed by a meta-regression analysis. Results Twenty-two papers were included in the systematic review. The overall estimated prevalence of tooth erosion was 30.4% (95%IC 23.8–37.0). In the multivariate meta-regression model use of the Tooth Wear Index for clinical examination, studies with sample smaller than 1000 subjects and those conducted in the Middle East and Africa remained associated with higher dental erosion prevalence rates. Conclusions Our results demonstrated that the estimated prevalence of erosive wear in permanent teeth of children and adolescents is 30.4% with high heterogeneity between studies. Additionally, the correct choice of a clinical index for dental erosion detection and the geographic location play an important role for the large variability of erosive tooth wear in permanent teeth of children and adolescents. Clinical significance The prevalence of tooth erosion observed in permanent teeth of children and adolescents was considerable high. Our results demonstrated that prevalence rate of erosive wear was influenced by methodological and diagnosis factors. When tooth erosion is assessed, the clinical index should be considered.
Summary
Tooth wear is a multifactorial condition, leading to the loss of dental hard tissues, viz. enamel and dentine. Tooth wear can be divided into the subtypes mechanical wear (attrition and ...abrasion) and chemical wear (erosion). Because of its multifactorial aetiology, tooth wear can manifest itself in many different representations, and therefore, it can be difficult to diagnose and manage the condition. A systematic approach is a sine qua non. In the below‐described tooth wear evaluation system (TWES), all necessary tools for a clinical guideline are present in different modules. This allows the dental clinician, in a general practitioner setting as well as in a referral practice setting, to perform a state‐of‐the‐art diagnostic process. To avoid the risk of a too cumbersome usage, the dental clinician can select only those modules that are appropriate for a given setting. The modules match with each other, which is indispensable and essential when different modules of the TWES are compared. With the TWES, it is possible to recognise the problem (qualifying), to grade its severity (quantifying), to diagnose the likely causes and to monitor (the progress of) the condition. In addition, a proposal for the classification of tooth wear is made. Further, it is possible to determine when to start a treatment, to make the decision which kind of treatment to apply and to estimate the level of difficulty of a restorative treatment.
– Traumatic dental injuries (TDIs) of permanent teeth occur frequently in children and young adults. Crown fractures and luxations are the most commonly occurring of all dental injuries. Proper ...diagnosis, treatment planning and followup are important for improving a favorable outcome. Guidelines should assist dentists and patients in decision making and for providing the best care effectively and efficiently. The International Association of Dental Traumatology (IADT) has developed a consensus statement after a review of the dental literature and group discussions. Experienced researchers and clinicians from various specialties were included in the group. In cases where the data did not appear conclusive, recommendations were based on the consensus opinion of the IADT board members. The guidelines represent the best current evidence based on literature search and professional opinion. The primary goal of these guidelines is to delineate an approach for the immediate or urgent care of TDIs. In this first article, the IADT Guidelines for management of fractures and luxations of permanent teeth will be presented.
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