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Structural diseases in childhood Abnormalities of tooth structure Defective enamel (dentin) formation may be caused by genetic or environmental factors 2015.11.18. 2 Dental enamel • Dental enamel is a highly mineralized tissue with over 95% of its volume occupied by unusually large, highly organized, hydroxyapatite crystals. Enamel • Dental enamel, the most highly mineralized structure in the human body, is formed within a unique, extracellular matrix derived through the synthesis and secretion of proteins by the ameloblast cells. Enamel • Proteins in the enamel: ameloblastin, enamelin, tuftelin, amelogenin etc.. • AMELX, ENAM, MMP20, KLK-4 etc genes provide instructions for making protein that are essential for the normal development. 2015.11.18. 5 Enamel formation Dental enamel formation is divided into: • pre-secretory, • secretory, • transition, • maturation stages Enamel • The main structural proteins in forming enamel are amelogenin, ameloblastin, and enamelin. • During the secretory stage, enamel proteins are being secreted along with proteases, creating a complex mixture of enamel matrix constituents. • During the transition stage there is an increase in proteolytic activity, and in maturation stage the accumulated enamel proteins nearly disappear from the matrix. • Amelogenin: more than 90% of total enamel protein • Ameloblastin: 5% • Enamelin: 2% of total protein Amelogenin • Amelogenin is thought to form a scaffold for enamel crystallites and to control their growth, but its exact functions are not fully known. • At least 15 mutations Ameloblastin (Amelin) • Ameloblastin, also known as amelin, is expressed by the enamelproducing ameloblast cells • the ameloblastin gene is located in chromosome 4 • ameloblastin is a key adhesion molecule for enamel formation and suggest that ameloblastin plays an important role by binding to, and maintaining the differentiated phenotype of secretory ameloblasts. Enamelin • Enamelin, the largest enamel extracellular matrix protein, • It is produced by ameloblasts, initially during the secretory stage. • At least 7 mutations Metalloproteinase MMP20 PROTEINASES • Different proteinases, serving different functions. These proteinases are believed to regulate the enamel matrix protein processing that ultimately defines the structure and composition of enamel. The predominant proteinases are matrix metalloproteinase-20 in secretory enamel matrix • At least 2 mutations 3 level: • Hypoplasia • Hypocalcification • hypomaturation Amelogenesis imp. Can have different inheritance pattern depending on the gene that is altered. ENAM – autosom. Dom (AD) ENAM and MMP20 – autosom. Rec (AR) AMELIX – X linked 2015.11.18. 14 Classification (Witkop) Amelogenesis imperfecta • Represents a classic example of heritable enamel defect • All teeth involved • There are 14 subgroup classifications • The prevalence varies from 1:700 to 1:14,000, according to the populations studied - Hypoplastic type- insufficient quantity of enamel is formed - Hypocalcification type- quantity normal but the matrix is poorly calcified - Hypomaturation type- low value of radiodensity and mineral content 2015.11.18. 16 Amelogenesis imp. • Amelogenesis imp. Classification based on the mode of inheritance : autosomal dominant, autosomal recessive, X-linked or apparently sporadic • A. dominant – male and female are equally affected, both dentition involved amelogenin gene on the chromosome 4 has been shown to be mutated • A. recessive in isolated communities when the parents are close relatives, first cousins.. 2015.11.18. 17 Diagnosis based on the phenotype (appearance), and the mode of inheritance TYPE I: HYPOPLASTIC AI • All of the hypoplastic AI subtypes are characterized by the primary feature of deficient amount of enamel formed. The decreased amount of enamel varies in the different subtypes and can be characterized by enamel that is pitted, has grooves or furrows, has large areas of missing or very thin enamel surrounded by more normal enamel, or enamel that is very thin over the entire tooth crown • Crowns size varies from small to normal, small teeth may lack proximal contacts, color varies from normal to opaque white – yellow brown AI type I, hypoplastic X-linked • Heterozygous females can pass on the mutant gene to children of either sex with the risk of this being 50%. The condition affects males and females in different ways. • Males may have teeth which have only a thin layer of enamel of normal color and translucency, or the enamel may be of normal thickness but poorly mineralized with loss of translucency and/ or a yellow-brown discoloration AI type I, hypoplastic X-linked • Females may have teeth with vertical ridges and grooves as a result of hypoplasia of the enamel or have vertical bands of alternating normal and discolored enamel. Amelogenesis imperfecta AD • Autosomal dominant AI typically affects one or more individuals in each generation of a family • The phenotype in AI - AD may be predominantly or exclusively hypoplastic, manifested by thin enamel and spacing between the teeth, roughness, irregular or randomly pitted enamel. Autosomal recessive AI • This may more often occurs in certain ethnic and cultural groups where intermarriage within the family is more common. • Enamel pitting with an anterior open bite Type II. hypomaturation AI • Commonly associated with an open bite and creamy to yellow-brown roughly surfaced teeth that may be tender and sore. • The enamel is generally normal in thickness but is unusually brittle. • Can be autosomal dominant, autosomal recessive, or X-linked. Type III. hypocalcified AI • Open bite and creamy to yellow-brown rough enamel-surfaced teeth that may be tender and sore. • The enamel is soft and may be lost soon after eruption leaving the crown composed only of dentin. The enamel has a cheesy consistency and can be scraped from the dentin • Large masses of supragingival calculus become deposited on the teeth AI – IV Type • A variant with taurodontism. • The sheath of Hertwig, that maps the shape of the roots of teeth, is a derivative of the enamel organ and is also responsible for differentiation of the inner dental epithelial cells to ameloblasts producing enamel proteins • smaller than normal teeth, the color of which may range from white to yellow-brown, and teeth that appear to be mottled or spotted. The enamel is thinner than normal with areas that are clearly less dense (hypomineralized) and pitted. Genetically these characteristics are transmitted as autosomal dominant traits. Environmental enamel hypoplasia Environmentaly induced enamel hypoplasia can result from systemic or local causes. Factors: (mother side) nutrition defiences fever producing disorders severe infections (rubeole, syphilis) asthma endocrine disturbances drugs radiation 2015.11.18. 27 Environmental enamel hypoplasia Factors: (child side) neorologic defects (cerebral palsy) asthma irradiation drugs (chemotherpy, steroid, antibiotics, endocrine diseases imundefficiency systemic diseases LOCAL: trauma, caries, 2015.11.18. tetracyclin, fluorid etc. 28 Chronological line 2015.11.18. 29 Defective enamel formation • Will exhibit either hypoplasia or hypocalcification and hypomaturation. • The neonatal line is manifest in all teeth, but unless there is severe hypoxia or fetal distress the disturbance will not be clinically evident 2015.11.18. 30 Linea neonatalis We must decide whether it is • Caries incipiens – macula cretosa (White spot) or a structural disease What helps: • • • • anamnesis Oral hygiene Family anamnesis Dietary information 2015.11.18. 33 Hypoplasia or early childhood caries? Turner tooth Structural disease follows chronology 2015.11.18. 36 Chrological line 2015.11.18. 37 hypolasia Fewer induced hypoplasia Chemotherapy induced hypoplasia and short roots Fluorosis • Depends on the age. It is critical in 2-3 years , when the fluoride is more than 1 ppm (part per million ) • Be careful! Tooth paste, drinks, tea etc • Dose dependent Fluorosis Tetracycline • Since their introduction in 1947, tetracyclines have been used in the treatment of various infections • Doxycycline is a semi-synthetic, lipophilic and potent tetracycline congener • causing enamel hypoplasia and irreversible staining of decidious teeth, staining of the permanent adult dentition • results from the formation of insoluble tetracycline-calcium orthophosphate complexes which are deposited in dentine and enamel and darken upon exposure to light • Calcification of permanent teeth begins around 4-6 months of life and is largely complete by 5-6 years. But do not give it before 8-9 years of life! • Vital bleaching with H2O2 and composite/porcelain veneers/crowns remain as the best possible therapeutic approaches Congetital syphilis Moon’s (mulberry) molars Hutchinson’s incisors Celiac disease(gluten intolerance) The enamel pitted, grooved or missing Late eruption and frequent aphtosis, ulcerations Vitamin D deficiency Non-Hodgkin lymphoma Molar hypoplasia or hypomineralization (MH) • Only the molars are involved MIH –molar incisal hypomineralization or hypoplasia • Not only the first molars but! the incisors as well • Different severity, opacity or loss of the whole enamel • FDI 1992 Modified defect of dental enamel (DDE) depends on the severity: mild enamel < 30% affected moderate – 31-50% severe – 50% or more signs • Discoloration, opacity, enamel loss • hypersensitivity • Inability to anesthetize • Rapid caries progression Causes: • Pre- and postnatal diseases Low birth weight • Antibiotics –Amoxicillin! • Prolonged breast feeding(dioxin) • Otitis media, pneumonia • Asthma • Urinary tract infections • Measles Az amoxicillin and fluoride!! According to Van Amerongen • The MIH severer than MH • The primary etiological factors of MH : 48% delivery problems, 67% respiratory infections • MIH : antibiotics, and/or other medicaments, otitis, long lasting fewer, early childhood infective diseases Weerheijm classification: • Opacity – • PEB - post eruptive enamel breakdown • Atypical restorations • Extractions due to MIH Treatment • Risk assessment • Early diagnosis • Remineralization (MI Paste) • Prevention (fissure sealing, fluoride, sensitive toothpaste) • Restoration (GIC???) • Crowns Dentin hypoplasia The condition causes the teeth to be discolored ( blue-gray, yellowbrown color) The teeth are also weaker, prone to rapid wear, breakage and loss Type I is in connection with osteogenesis imperfecta-bone are brittle and easily broken Type II and III with or without other inherited disorders Type II – hearing loss Type III – Brandywine type 2015.11.18. 57 Dentinogenesis imperfecta • Mutation of the DSPP gene can cause type II and III. Type I occurs as part of the osteogenesis imperfecta, which caused by mutation several other genes. 2015.11.18. 58 Dentinogenesis imperfecta • • • • Both in primary and permanent In primary severe inherited Same as in amelogenesis imperfecta: • hypoplasia • hypocalcification • hypomaturation 2015.11.18. 59 • Teeth are weaker than normal, making them prone to rapid wear, breakage, and loss • Radiographically, the teeth have bulbous crowns with constricted short roots. Initially, pulp chambers may be abnormally wide and resemble “shell teeth • The presence of an atubular area in the dentin with reduced mineralization and a reduced number of odontoblasts are consistent findings. • Pulpal inclusions and much interglobular dentin are also frequent. • Attrition may cause pulpal involvement with dental abscesses, • The short, constricted roots might break under load, thus necessitating extraction. • The severe attrition may result in a rapid decrease in the occlusal height. • 1. Maintain dental health and preserve vitality, form, and size of the dentition. • 2. Provide the patient with an esthetic appearance at an early age, in order to prevent psychological problems. • 3. Provide the patient with a functional dentition. • 4. Prevent loss of vertical dimension. • 5. Maintain arch length. • 6. Avoid interfering with the eruption of the remaining permanent teeth. • 7. Allow normal growth of the facial bones and temporomandibular joint (TMJ). • 8. Establish a rapport with the patient and the patient’s family early in the treatment • In the early primary dentition, soon after eruption it is generally necessary to protect the primary molars with stainless steel crowns. • In the restorative treatment of pediatric patients, glass ionomer with fluoride-releasing and chemically attaching materials are recommended for occlussally non-stressed areas • Polycarbonate crowns may offer an alternative for the restoration of the anterior primary teeth. • An acrylic overlay denture, resting over the remnants of crowns and roots of the primary dentition, also has been used successfully. • Dentinogenesis imperfecta estimated prevalence 1: 6,000 - 8,000. 2015.11.18. 65 Dentinogenesis Imperfecta Osteogenesis imperfecta Dentin Dysplasia • Dentin Dysplasia (DD), a rare anomaly is an autosomal dominant hereditary disturbance in dentin formation affecting either the primary or both the dentitions in approximately one patient in every 100,000 Dentin Dysplasia • Type I DD is characterized by crowns appearing normal or might be slightly amber colored with no or only rudimentary root development, aberrant growth of dentin in the pulp chamber leading to reduced pulp space in permanent teeth and incomplete or total obliteration of the pulp chambers, and periapical radiolucent areas or cysts which might result in premature loss of tooth Dentin Dysplasia • DD type II is characterized by yellow, brown, grey amber, translucent primary teeth with complete pulpal obliteration. The permanent teeth have a normal appearance or might be slightly amber colored. Roots are normal in size and shape with a ‘thistle tube’ shaped pulp chamber with pulp stones. Obliteration of pulp chamber does not occur before eruption Regional odontodysplasia • rare, severe developmental anomaly affecting the formation of the teeth. • affects the structures derived from epithelial and mesenchymal components of the teeth, which include enamel, dentin, pulp, and the dental follicle. • The roots are short with open apices and the pulp appears much larger than normal with little definition or contrast within the tooth structures.