Читать книгу Color Atlas of Oral Diseases in Children and Adolescents - George Laskaris - Страница 10
Оглавление1 Dental Defects
Nick A. Lygidakis Consultant Paediatric Dentist DDS, MScD, MScM, DrOdont
Marina G. Laskari Orthodontist, DDS, MSc Boston University, USA
Defects in Size
These defects result from various etiological factors acting during the stage of dental morphodifferentiation.
Microdontia
Definition
• Refers to teeth that appear smaller in size compared to normal. Pseudomicrodontia refers to all teeth of an individual appearing smaller than normal, as a result of enlarged jaw dimensions. True microdontia refers to teeth of smaller size in a jaw of normal size (Figs. 1.1, 1.2).
Etiology
• Multifactorial. Generalized microdontia is rare, and may be associated with congenital hypopituitarism or exposure to radiation or chemotherapy during dental development. In contrast, localized microdontia is more common, and is frequently followed by hypodontia; it has therefore been suggested that these two defects are controlled by different mutations in the same genes.
• Syndromes in which microdontia may be seen include the trisomy 21 syndrome, the ectodermal dysplasia syndromes, and the Marshall I, Rieger, focal dermal hypoplasia, Silver-Russell, Williams, Gorlin-Chaudhry-Moss, Coffin-Siris, Salamon, trichorhinophalangeal, odontotrichomelic, neuroectodermal, and dermo-odontodysplasia syndromes.
• Also a frequent finding in cases of cleft lip and palate.
Occurrence in children
• Rare (less than 1%) in primary teeth.
• More common (2.5%) in permanent teeth.
• Females more frequently affected than males.
Localization
• Upper laterals.
• Upper third molars.
Clinical features
• Usual crown shape or sometimes with tapering (peg or conical) crown, but smaller in size than the range of normal variation.
Treatment
• Aesthetic restoration with composites, crowns in severe cases, orthodontic treatment for closure of spaces, if needed.
Macrodontia
Definition
• Refers to teeth that appear larger than the normal size. Some or all teeth may be affected (Fig. 1.3).
Etiology
• Multifactorial. Generalized macrodontia is observed in cases of pituitary gigantism, and in individuals with small jaws. Localized macrodontia is observed in cases of unilateral facial hyperplasia, resulting from over-development of tooth buds.
• Macrodontia may also be associated with congenital hemifacial hypertrophy and some genetic syndromes such as craniofacial dysostosis, otodental svndrome, and Sturge–Weber syndrome.
Occurrence in children
• Rare (1.1%) in permanent dentition.
Localization
• Lower third molars and second premolars.
• Upper central incisors.
• Frequent bilateral symmetry.
Clinical features
• Usual tooth morphology with rounded edges, exceeding in size the range of normal variation.
Complications
• Clinically, macrodontia may lead to crowding and potential abnormal teeth eruption as a result of reduced available space in the dental arch.
Treatment
• Aesthetic restoration and orthodontic treatment of the potential crowding.
Fig. 1.1 Microdontia of the upper lateral incisors
Fig. 1.2 Microdontia of a lower permolar
Fig. 1.3 Macrodontia of the upper and lower incisors in a patient with otodental syndrome
Conical Teeth
Definition
• Refers to teeth that have a conical shape with a pointed edge.
Etiology
• Frequently followed by hypodontia, and for this reason it has been suggested that these two anomalies are controlled by different mutations in the same genes (Fig. 1.4).
• In the majority of the cases, conical teeth are found in patients with genetic disorders such as ectodermal dysplasia, Rieger, dento-onychodermal and incontinentia pigmenti syndromes.
Occurrence in children
• Rare in both permanent and primary teeth (0.2%).
Localization
• Upper incisors.
Clinical features
• Characteristic conical shape with sharp, pointed edge.
Treatment
• Aesthetic restoration with composites, crowns.
Defects in Shape
These defects manifest as a result of various etiological factors acting during the initiation/proliferation and the morphodifferentiation stages of dental development.
Gemination
Definition
• Refers to incomplete division of the tooth bud, resulting in the formation of two partially or completely independent crowns with a shared root (Fig. 1.5). If the division is complete, the anomaly is termed twinning, and results in the formation of a supernumerary tooth, which appears as a minor image of its normal partner.
Etiology
• This defect can be found in both the primary and permanent dentitions, and results from various degrees of invagination of the developing dental organ caused by local, systemic, and genetic factors.
• The genetic factors involved are probably similar to those affecting the dental lamina in cases of hyperdontia.
Occurrence in children
• Including fusion, rare in both primary (0.5–1.6%) and in permanent 0.1–0.2% teeth.
• Males and females equally affected.
• 30–50% of the primary cases are followed by defects in the permanent successors.
Localization
• Upper and lower incisors.
Clinical features
• Variable, from a minor notch in the incisal edge of a wide crown to almost two separate crowns. Similarly, the pulp chamber and the root canal may be common to both elements, or separate for each one.
Complications
• Potential crowding of the dental arch. Difficulty in the differential diagnosis between gemination and fusion of a normal and supernumerary tooth.
Treatment
• Aesthetic restoration with composites, or surgical removal of the supernumerary in cases of twinning. Orthodontic treatment of the potential crowding.
Fig. 1.4 Conical teeth in a patient with hypohidrotic ectodermal dysplasia
Fig. 1.5 Gemination of an upper lateral incisor
Fusion
Definition
• Refers to the union of two discrete tooth buds, resulting in the formation of a tooth with an anomalous shape.
Etiology
• The defect is a result of interdental lamina persistence during dental organ development, caused by local factors.
• Genetic factors have also been implicated, such as autosomal dominant inheritance with reduced penetrance.
Occurrence in children
• Including gemination, it is rare in both primary (0.5–1.6%) and permanent (0.1–0.2%) teeth.
• Ethnic variations result in a higher incidence in some populations.
• 30–50% of the primary cases are followed by defects in the permanent successors.
Localization
• Anterior teeth.
Clinical features
• If fusion occurs early during the tooth development, the defect affects the total length of the tooth, resulting in a single tooth of almost normal size.
• If fusion occurs later, the defect only affects the root (Fig. 1.6), resulting in shared dentine and cementum, and one large tooth or a tooth with bifid crown.
Complications
• Fusion most often leads to a reduced number of teeth in the dental arch, although occasionally a normal and a supernumerary tooth may be fused. In the latter case, there is difficulty in the differential diagnosis between this defect and gemination. Fusion in the primary dentition may be followed by aplasia of the permanent successor.
Treatment
• Aesthetic restoration with composites, or surgical separation and removal of the fused supernumerary tooth. Orthodontic treatment of the potential crowding.
Concrescence
Definition
• Refers to a type of fusion in which the formed teeth are joined only along the line of cementum.
Etiology
• This defect can happen before or after the teeth erupt, and is most probably a result of local trauma, dental crowding, and dislocation of tooth germs during root formation.
Occurrence in children
• Rare.
Localization
• Upper second and third molars.
Clinical features
• Diagnosis of the alteration can be definite only with radiographs.
Complications
• The defect does not have any clinical significance except in cases in which extractions are needed and appropriate surgical manipulations should be followed.
Treatment
• No treatment is required, since the affected teeth are asymptomatic.
Dilaceration
Definition
• Refers to an extensive bend in the root on the cervical area of the affected teeth.
Etiology
• The defect results from disruption of the Hertwig epithelial root sheath due to eccentric dislocation of the already formed crown in relation to the developing adjacent soft tissues (Figs. 1.7, 7.8).
• Dilaceration has been associated with trauma of the predecessor primary teeth during the developmental period of the permanent tooth, or with therapeutic irradiation of the area.
Occurrence in children
• Rare.
• 3% of the successors in cases of traumatized primary teeth.
Localization
• Anterior teeth.
Clinical features
• Malformed crown, frequently hypoplastic, and severe deviation of the long axis of the crown or root segment of the tooth.
Complications
• Clinical problems caused by the defect include difficulties in case of extraction, and the frequent impaction of these teeth.
Treatment
• In case of normal eruption, aesthetic or prosthetic restoration. In case of impaction, combined surgical and orthodontic treatment in order to align the tooth in the dental arch, followed by aesthetic restoration.
Fig. 1.6 Fusion of lower primary lateral incisors and canines
Fig. 1.7 Dilaceration, mesial-distal, of an upper central incisor due to trauma in the predecessor primary tooth
Fig. 1.8 Dilaceration, buccal-palatal, of an upper central incisor due to trauma in the predecessor primary tooth
Dens Invaginatus (Dens in Dente)
Definition
• Refers to a defect characterized by a prominent lingual cusp and a centrally located pit (Fig. 1.9).
Etiology
• The defect results from early invagination of the enamel epithelium into the dental papilla of the underlying tooth germ. Local and genetic factors have been implicated.
Occurrence in children
• Rare in primary teeth.
• More common in permanent teeth (1–5%).
Localization
• Upper permanent lateral incisors, usually bilateral.
Clinical features
• The defect may not be clinically apparent, and does not frequently cause problems. If present, the labial surface of the tooth is normal, whereas the defect in the lingual surface may vary from a deep cingulum pit to a tooth with grossly distorted crown and root.
• Three types of the defect are recognized, depending on the extension of the cavity into the root.
Complications
• Increased frequency of caries in the lingual pits of the affected teeth due to the thin and incomplete layer of enamel, followed occasionally by pulp inflammation and necrosis, as a result of improper brushing and cleaning of the involved area.
Treatment
• Preventive filling of the pit. In case of odontogenic infection, endodontic treatment of the tooth.
Dens Evaginatus
Definition
• Refers to a defect characterized by an elevated, tuberculated appearance of the occlusal surface of the affected teeth. Evaginations contain enamel, dentine, and pulp (Fig. 1.10).
Etiology
• The defect results from focal hyperplasia of the ectomesenchyme of the primitive dental papilla. Genetic factors acting during the developmental period of the teeth have been implicated.
Occurrence in children
• Rare (less than 1%).
• Frequent finding in individuals of Mongolian origin (1–4%).
Localization
• Premolars and molars, usually bilaterally.
Clinical features
• The affected teeth have a conical, tuberculated projection from the central fissure of the occlusal surface.
Complications
• Pulp may extend into the tubercula, resulting in an increased risk of pulp exposure after mild mechanical trauma to the occlusal surface.
Treatment
• Reduction of the occlusal tubercula (cusp) in order to induce formation of secondary dentine, or reduction of the opposing tooth in order to eliminate possible traumatic occlusion.
Taurodontism
Definition
• Refers to a dental defect usually found in multirooted teeth. It is characterized by a prolonged crown and more apically located root furcation, resulting in the creation of enlarged pulpal chambers with increased occlusal-apical length (Fig. 1.11). Three types of the defect have been recognized, termed hypotaurodontism, mesotaurodontism, and hypertaurodontism according to the extension of the pulp chamber into the root.
• The defect has also been classified among pulp dysplasias.
Etiology
• Polygenic, with additional implication of local factors. The defect has been attributed to the failure of the Hertwig’s epithelial root sheath to invaginate below the crown at the proper time during dental development.
• Taurodontism is frequently found in patients with trisomy 21 and Klinefelter syndromes, as well as other chromosomal anomalies involving an abnormal number of X chromosomes.
• It is also found in cases of type IV amelogenesis imperfecta, trichodento-osseous syndrome types I, II, III, Down’s syndrome, ectodermal dysplasia, and some other syndromes.
Occurrence in children
• Rare in primary teeth.
• More common in permanent molars (6–10%).
Localization
• First and second molars.
• Frequently a bilateral finding.
Clinical features
• Definite diagnosis only with radiographs revealing vertical enlargement of the coronal pulp chamber extending below the cervical area of the tooth. The bifurcation or the trifurcation of the root is displaced apically.
Complications
• Needs special care in case of endodontic treatment.
Treatment
• No treatment is required, since the affected teeth are asymptomatic.
Fig. 1.9 Dens in dente (dens invaginatus) of an upper central incisor, resulting in pulpal necrosis
Fig. 1.10 Dens evaginatus in an upper molar
Fig. 1.11 Radiological features of taurodontism in a lower second molar
Enamel Pearls
Definition
• Refers to ectopic nodular deposits of enamel observed at the roots of the involved teeth (Figs. 1.12, 1.13). Two types have been recognized: extradental and intradental.
Etiology
• Unknown. These defects arise from local activity of the Hertwig’s epithelial root sheath remnants.
Occurrence in children
• Rare.
• Higher incidence in Mongoloid and Eskimo populations.
Localization
• Upper molars.
Clinical features
• Diagnosis of the defect is only possible with radiographs.
• They are usually found near the root furcations of single or multirooted teeth, and their size varies from a pinhead to a cusp. Occasionally, they contain dentine as well as enamel, and the pulp usually extends into them.
Treatment
• No treatment is required, since the affected teeth are asymptomatic.
Odontomas
Definition
• Refers to odontogenic hamartomatous "tumors" containing dental calcified tissues.
Etiology
• Unknown. These structures are malformations rather than tumors, originating from the dental tissues or their formative elements.
Occurrence in children
• Rare (0.15 per thousand).
• These are the most frequent odontogenic "tumors" (67%).
Localization
• Compound and mixed odontomas more frequently in the anterior maxilla.
• Complex odontomas more frequently in the premolar/molar region of both jaws.
• Primary dentition is rarely involved (2% of the cases).
Clinical features
• Odontomas are asymptomatic and frequently diagnosed radiographically (Fig. 1.14).
• They are classified in two major types. Compound odontomas are masses composed of multiple, discrete, small, tooth-like formations with well-recognized dental hard tissues, whereas complex odontomas are a more homogeneous mass of disorganized different anomalous dental tissues. Sometimes both types exist simultaneously, and the defect is termed mixed odontoma.
Complications
• Frequently (30–50%), they cause disturbance or total failure of eruption of the adjacent permanent teeth.
Treatment
• Surgical removal of the odontoma and, in case of eruption disturbances of the adjacent permanent teeth, orthodontic treatment.
Fig. 1.12 Enamel pearl in the cervical furcation of an upper first molar
Fig. 1.13 Radiological features of enamel pearl in the root of an upper first molar
Fig. 1.14 Radiological features of odontomas in the upper anterior region resulting in eruption failure of the adjacent tooth
Defects in Location
These defects result from etiological factors acting during the initiation and proliferation stages of dental development.
Ectopic Localization, Eruption
Definition
• Refers to a defect characterized by the eruption of a normal tooth into another location in the dental arch.
Etiology
• The defect results from ectopic placement of the tooth bud, or an irregular eruption path (Fig. 1.15). This is either caused by congenital migration of the tooth bud at the start of embryogenesis, related to genetic and environmental factors, or by displacement of the tooth during eruption, related to local factors.
• Local factors implicated are tooth-dental arch size discrepancy, prolonged primary tooth retention, presence of clefts, ankylosis, cystic or neo-plastic formations, trauma. Generalized factors implicated are endocrine deficiency, febrile disease and irradiation.
Occurrence in children
• Ectopic location, rare.
• Ectopic eruption, 0.9–2.0%.
• Females more frequently affected than males (2:1).
Localization
• Canines and incisors.
• First permanent molars.
• Maxillary teeth more frequently affected than mandibular (3:1).
Clinical features
• A radiographically normal tooth located or erupting at an abnormal site.
Complications
• Frequently, ectopic localization/eruption is followed by impaction of the tooth concerned. Resorption of the adjacent teeth can also be found in some cases, particularly in the case of permanent molars.
Treatment
• Orthodontic treatment. Combined surgical-orthodontic approach in case of impaction.
Defects in Number
These defects result from the action of various etiological factors during the initiation and proliferation stages of the dental development.
Anodontia, Hypodontia
Definition
• Refers to a defect characterized by congenital absence from the dental arch of some teeth (hypodontia) or all of them (anodontia) (Figs. 1.16, 1.17). Severe hypodontia is also termed oligodontia.
• Anodontia and hypodontia may affect both the primary and permanent dentition. Pseudohypodontia is characterized by the absence of teeth from the dental arch due to impaction, delay of eruption, or early exfoliation.
Etiology
• The defect results from dental lamina obstruction or disruption during the early stages of embryogenesis, caused by abnormal activity of local, systemic, and genetic factors. Genetic factors, usually multigenic, have been strongly implicated.
• Hypodontia and anodontia are frequently associated with more than 70 genetic disorders and syndromes, primarily with those characterized by ectodermal involvement, such as the ectodermal dysplasias and the following syndromes: Rieger’s, incontinentia pigmenti, Robinson’s, Seckel’s, orofaciodigital, focal dermal hypoplasia, Hallermann-Streiff, oculoden-todigital, Russell-Silver, chondroectodermal dysplasia, frontometaphyseal dysplasia, craniofacial dysplasia, and others. It is also a frequent finding in patients with cleft lip and cleft palate.
Occurrence in children
• Anodontia: rare.
• Hypodontia of primary teeth: 0.1–0.7%.
• Hypodontia of permanent teeth, excluding third molars: 3.0–7.5%.
• In hypodontia, two or more teeth are involved in 50% of the cases.
• Considerable ethnic variation.
Localization
• Third molars, upper lateral incisors, second premolars.
Clinical features
• Missing teeth, spacing, and occasionally abnormal location in the remaining teeth.
Complications
• Aesthetic and mastication problems.
Treatment
• Orthodontic and prosthetic treatment, implants.
Fig. 1.15 Ectopic location and eruption of a lower lateral incisor
Fig. 1.16 Anodontia in a patient with hypohidrotic ectodermal dysplasia
Fig. 1.17 Hypodontia in a patient with hypohidrotic ectodermal dysplasia
Supernumerary Teeth
Definition
• Refers to a condition characterized by the presence of supernumerary teeth in the dental arch. These teeth may be either of normal morphology (supplemental) or, more frequently, are anomalous, with irregular size and shape (accessory).
Etiology
• The defect results from continuing abnormal activity of the dental lamina, which leads to the formation of supernumerary tooth buds. The etiology of the defect is multifactorial, although there is a strong genetic background under the control of several different loci.
• Frequent finding in patients with Gardner’s syndrome, cleidocranial dysplasia, Hallermann-Streiff syndrome, and orofaciodigital syndrome type I.
Occurrence in children
• Primary dentition 0.3–0.6%, permanent dentition 1.0–3.5%.
• More frequently observed in the maxilla, by a ratio of 9:1.
• Supernumeraries in the primary dentition may be followed by supernumeraries in the permanent dentition in 30–50% of cases.
• Males more frequently affected than females (2:1).
• Ethnic variation.
Localization
• Near the middle line in the incisal region of the maxilla (mesiodens).
• Beyond the third molar (distomolars) or in the molar area (paramolars).
Clinical features
• Supplemental or conical, tuberculate, and odontoma-like shape (Figs. 1.18, 1.19).
• 75% of these teeth remain impacted in the bone, and are diagnosed only radiographically.
Complications
• In the case of impacted supernumerary teeth, there is an increased possibility of inhibited or delayed eruption of adjacent teeth. If the supernumeraries erupt in the dental arch, they usually cause functional and aesthetic problems.
Treatment
• Removal of the supernumerary teeth and orthodontic treatment of the affected area.
Defects of Eruption and Exfoliation
These defects result from the action of various etiological factors during the eruption stage of the dental development.
Eruption Defects
Early eruption
Definition
• This refers to accelerated eruption of either the primary or permanent teeth. In addition, the term "natal teeth" refers to primary teeth that have already erupted at birth (Fig. 1.20), whereas neonatal teeth are teeth erupting within one month after birth. These two defects usually represent regular primary teeth with imperfect roots, although sometimes they are supernumerary.
Etiology
• Multifactorial, implicating local, systemic, and strong genetic factors. Early eruption of primary and permanent teeth can be found in the following syndromes: pycnodysostosis, hemihypertrophy, holoprosencephaly, Sotos, Klippel–Trenaunay–Weber, Sturge–Weber.
• Excluding cases of isolated random occurrence of natal teeth, this defect may be associated with certain genetic disorders, such as the following syndromes: Ellis–van Creveld, Hallermann–Streiff, Saldino–Noonan, odonto-onychodysplasia, pachonychia congenita, X-linked ectodermal dysplasia.
Complications
• Frequently, natal teeth cause great difficulties in breast feeding, since they are usually lower central incisors.
Treatment
• In case of early eruption, no treatment is required. In case of natal teeth, extraction because of feeding problems is indicated.
Fig. 1.18 Erupted supernumerary teeth (mesiodens) in the upper anterior area
Fig. 1.19 Radiological features of upper anterior supernumerary teeth, resulting in eruption delay of the adjacent central incisors
Fig. 1.20 Natal teeth in a newborn baby
Delayed eruption
Definition
• This refers to delay of eruption by more than six months for primary teeth, or more than 6–10 months for permanent teeth (Figs. 1.21, 1.22).
Etiology
• Delayed eruption can be caused by either local or systemic factors and genetic disorders.
Local factors
• Space loss and dental crowding
• Trauma, radiation
• Supernumerary teeth, odontomas
• Delay of primary teeth exfoliation
• Early primary teeth exfoliation
• Dentigerous cyst, eruption cyst
• Dilaceration
• Pathological local defects of bone or soft tissues
Genetic/systemic disorders
• Vitamin D–resistant rickets
• Hypothyroidism
• Fibrous dysplasia
• Pycnodysostosis
• Cleidocranial dysplasia
• Down’s syndrome
• Incontinentia pigmenti
• Gardner’s syndrome
• Focal dermal hypoplasia (Goltz syndrome)
• Osteopetrosis
• Pseudohypoparathyroidism (Albright hereditary osteodystrophy)
• Apert syndrome
• Growth retardation, alopecia, pseudo-anodontia, and optic atrophy (GAPO) syndrome
• Mucopolysaccharidosis I, II, VI
• Mucolipidosis II
• Faciogenital dysplasia (Aarskog’s syndrome)
• Cornelia de Lange syndrome
• Schinzel–Giedion syndrome
• Prader–Willi syndrome
• Otodental syndrome
• Robinson’s syndrome
• Amelo–onychohypohidrotic dysplasia
Complications
• Usually, severe dental crowding in the affected area.
Treatment
• In case of delayed tooth eruption caused by local etiological factors, removal of the factor and orthodontic evaluation followed by surgical or orthodontic treatment, or both, when needed.
Ankylosis
Definition
• Ankylosis appears clinically as an eruption defect, frequently followed by irregular occlusion. It is characterized by occlusal surface retention of the affected teeth, at a level at least 1 mm or more cervical to the adjacent teeth (Fig. 1.23).
Etiology
• The defect is caused by local traumatic and metabolic factors, whereas genetic factors have also been implicated. It is the result of continuing eruption of the adjacent teeth in contrast to the immobilization of the affected teeth.
Occurrence in children
• Primary teeth 1.3–9.9%.
• Coexistence of missing successors 11–20%.
• Permanent teeth, rare compared to primary (1:10).
Localization
• Primary and permanent molars.
• More frequently in the mandible.
• Frequently a bilateral finding.
Clinical features
• Occlusal surface at least 1 mm cervically compared to adjacent teeth.
• Sharp, clear sound on percussion.
• Absence of regular mobility.
• Three clinical forms: mild, moderate, severe.
Radiological features
• Break of periodontal membrane continuity.
• Absence of findings in ankylosed buccal and lingual surfaces.
• Findings in 30% of the cases with ankylosed proximal surfaces (Figs. 1.24, 1.25).
Complications
• In moderate and severe cases, the defect usually causes orthodontic disturbances in the involved area, resulting from malalignment of the adjacent and opponent teeth.
Treatment
• Depending on the severity of the ankylosis, a) follow-up of the resorption rate of the ankylosed tooth and possible build-up; b) mechanical luxation;c) extraction and orthodontic treatment.
Fig. 1.21 Eruption delay of upper central incisors due to impacted odontomas and supernumerary teeth
Fig. 1.22 Eruption delay of upper and lower anterior teeth due to impacted supernumerary teeth in a patient with cleidocranial dysplasia
Fig. 1.23 Radiological features of moderate ankylosis of a lower second primary molar
Early Exfoliation
Definition
• Refers to early loss of either primary or permanent teeth.
Etiology
• The condition results frequently from trauma, periodontal disease, and extraction due to caries. However, some genetic and systemic disorders may cause early loss of teeth as a result of damage to either soft periodontal tissue or bone (Fig. 1.26).
Genetic/systemic disorders
• Prepubertal periodontitis
• HIV periodontitis
• Hypophosphatasia
• Acatalasia
• Papillon–Lefevre syndrome
• Gingival fibromatosis and hypertrichosis
• Oculodentodigital syndrome, type I
• Ehlers–Danlos syndrome, type VIII
• Progeria
• Vitamin D–resistant rickets
• Diabetes mellitus
• Glycogen storage disease, Type Ib
• Langerhans cell histiocytosis
• Cyclic neutropenia
• Leukemia
• Inherited immunodeficiencies
• Acrodynia
• Neoplasms
• Hajdu–Cheney syndrome
• Chediak–Higashi syndrome
• Ellis–van Creveld syndrome
Enamel Defects
These defects result from the action of various etiological factors during the apposition and mineralization stages of dental development.
Fig. 1.24 Radiological features of severe ankylosis of a lower first permanent molar
Fig. 1.25 Radiological features of mild and moderate ankylosis of the upper and lower primary molars
Fig. 1.26 Early exfoliation of an upper primary molar due to periodontitis in a patient with cyclic neutropenia
Definition
• The range of enamel defects covers a group of defects clinically recognizedas enamel hypoplasia, hypocalcification, hypomaturation (demarcatedand diffuse enamel opacities), or a combination of the former, dependingon the phase of amelogenesis that the etiological factor acts on.
Etiology
• Defective formation of the enamel matrix results in hypoplasia; defective calcification of an otherwise normal quantity of organic matrix results in hypocalcification; and defective formation of the crystallites in various areas of the enamel rods and sheaths results in hypomaturation (opacities).
• The whole range of enamel defects may be attributed to local, systemic, and genetic etiological factors. The clinical features are similar, although in defects of local etiology, single teeth are involved, whereas in those of systemic etiology all the teeth developing during the time of action of the etiological factor are affected (chronological defect). The genetic defects represent a separate nosological entity, usually affecting all the teeth, primary and permanent, and they are further divided into isolated enamel defects, termed amelogenesis imperfecta, and enamel defects associated with genetic disorders or syndromes.
Local factors
• Trauma, chronic infection, local surgery, cleft lip and palate, radiation, burns, osteomyelitis, jaw fracture.
Systemic etiological factors
Prenatal (defects in primary teeth)
• Various maternal diseases such as Vitamin A and D deficiency, diabetes mellitus, infections such as syphilis, rubella, cytomegaloviral infection, maternal alcoholism, toxemia, hypertension, malnutrition, hypoparathyroidism, cardiac, renal and pulmonary diseases, anemia, prolonged taking of medicines.
Perinatal and neonatal (defects in primary and permanent teeth)
• Neonatal hypocalcemia, severe perinatal and neonatal hypoxic injury, prolonged delivery, prematurity, low birth weight, twins, cerebral injury, neurological disorders, hyperbilirubinemia, prolonged neonatal diarrhea and vomiting, severe neonatal infections, high fever.
Postnatal (defects in permanent teeth)
• Nutritional and gastrointestinal disturbances resulting in hypocalcemia and vitamin D deficiency, bacterial and viral infections (particularly those with high fever), exanthematous diseases, juvenile hypothyroidism, hypoparathyroidism, hypogonadism, phenylketonuria, alcaptonuria, renal disorders, congenital heart disease, congenital allergy, oxalosis, mercury poisoning (acrodynia), fluorosis, prolonged use of medicines, prolonged diarrhea and vomiting, radiation and cytotoxic therapy.
Occurrence in children
• Frequent in primary dentition (33%).
• Frequent in cases of local etiology; 12–23% in permanent teeth following trauma or chronic inflammation in the predecessor primary teeth.
• Frequent in cases of systemic etiology; 71 % in children with a history of prenatal insult.
• Approximately 70 genetic disorders are associated with enamel defects.
Localization
• In cases of local etiology, mainly in permanent incisors and premolars.
• In cases of systemic etiology, mainly in the primary molars and permanent incisors and molars, but also in all the teeth developing during the period of action of the etiological factor.
• In cases of genetic etiology, all teeth in both primary and permanent dentitions may be involved.
Clinical features
• Hypoplasia, pits, grooves, and lines in the whole enamel surface or in certain areas. Possible reduction of the enamel thickness (Figs. 1.27–1.29).
• Hypocalcification, soft enamel of yellow-brownish color, easily removed by probing in isolated areas of the enamel, enamel attrition, sensitivity in thermal stimuli (Figs. 1.30, 1.31).
• Hypomaturation (opacities), dull enamel with mottled, white, opaque appearance and regular thickness, reduced hardness and possible microfractures (Fig. 1.32).
Complications
• Occasional occlusal distortion, aesthetic problems, sensitivity.
Treatment
• Conservative aesthetic restorations, prosthetic rehabilitation.
Fig. 1.27 Enamel hypoplasia and hypomineralization of all the primary teeth (chronological) resulting relaxing medicines during pregnancy
Fig. 1.28 Enamel hypoplasia and hypomineralization of an upper central incisor due to mechanical trauma of the predecessor primary tooth
Fig. 1.29 Enamel hypoplasia of all the permanent teeth (chronological), resulting from prolonged use of medicines for chronic nephritic syndrome
Amelogenesis Imperfecta
Definition
• The term "amelogenesis imperfecta" characterizes isolated defects of the enamel resulting exclusively from genetic factors and not associated with generalized genetic disorders and syndromes. This proposed terminology has been questioned recently, since other local abnormalities associated with amelogenesis imperfecta have been found, such as skeletal anterior open bite. In addition, the assumption of an isolated enamel defect in amelogenesis imperfecta may not be correct, since it depends on the clinician’s ability to diagnose other abnormalities else-where in the body.
Etiology
• The defect results from genetic factors acting during embryogenesis, particularly in the phases of enamel formation.
• Recently, it has been suggested that the anomaly results from a defect in the enamel matrix proteins amelogenin and enamelin. The amelogenin gene has been located in the p22.1–22.3 region of the X chromosome and in the pericentromeric region of the Y chromosome. The X-linked types of amelogenesis imperfecta are therefore strongly associated with a molecular defect in this locus.
• They are classified into many types, according to their clinical features and mode of inheritance.
Classification
Type I, hypoplastic
• la: pitted hypoplastic, autosomal dominant (Fig. 1.33)
• lb: local hypoplastic, autosomal dominant (Fig. 1.34)
• Ic: local hypoplastic, autosomal recessive
• Id: smooth hypoplastic, autosomal dominant (Fig. 1.35)
• Ie: smooth hypoplastic, X-linked dominant
• If: rough hypoplastic, autosomal dominant (Fig. 1.36)
• Ig: rough hypoplastic (enamel agenesis), autosomal recessive
Type II, hypomature
• Ila: hypomature pigmented enamel, autosomal recessive
• lib: hypomature enamel, X-linked recessive (Fig. 1.37)
• lie: snow-capped enamel, autosomal dominant
Type III, hypocalcified
• Ilia: hypocalcified enamel, autosomal dominant (Fig. 1.38)
• Illb: hypocalcified enamel, autosomal recessive (Fig. 1.39)
Type IV, hypomature-hypoplastic with taurodontism
• IVa: hypomaturation-hypoplasia with taurodontism, autosomal dominant
• IVb: hypoplasia-hypomaturation with taurodontism, autosomal dominant
Occurrence in children
• One per 4000–8000, all types
• 60–73% of the total hypoplastic types, 20–40% hypomaturation types, 7% hypocalcified types
Localization
• All teeth, primary and permanent
Clinical features
Hypoplasia
• Normal or reduced enamel thickness throughout the whole surface, or in isolated areas.
• Enamel pits, grooves, fissures and linear depressions randomly distributed over the entire enamel surface.
• Hard enamel with a normal or slightly yellow-brown color.
• Frequent microfractures of the enamel, and possible attrition.
• Types Id, Ie, and If appear clinically as teeth to have been prepared for jacket crowns.
Hypocalcification
• Regular enamel thickness at the time of tooth eruption.
• Soft enamel easily removed.
• Gradual reduction of the thickness resulting from easy attrition.
• Only dentine remains in severe forms of the defect.
• Increased sensitivity in thermal stimuli.
• Yellow-brownish color of the enamel, with pigment deposition.
• Associated occasionally with anterior skeletal open-bite.
Hypomaturation
• Opaque mottled enamel of normal thickness.
• Enamel approaches the radiodensity of dentine.
• Relatively soft enamel with frequent microfractures.
• Mottled brownish-yellow to white appearance.
Complications
• Occasional occlusal distortion, aesthetic problems, sensitivity.
Treatment
• Conservative aesthetic restorations; in severe cases, prosthetic rehabilitation.
Fig. 1.30 Enamel hypoplasia and hypomineralization of an upper central incisor, resulting from surgical intervention in the area when the patient was aged two
Fig. 1.31 Enamel hypomineralization and hypomaturation of an upper premolar, resulting from chronic pulpal infection of the predecessor primary molar
Fig. 1.32 Hypomineralization and hypomaturation (opacities) of the permanent incisors and molars, resulting from prolonged use of antibiotics for chronic infection in the neonate
Fig. 1.33 Hypoplastic pitted amelogenesis imperfecta (type Ia)
Fig. 1.34 Hypoplastic amelogenesis imperfecta with local hypoplasias (type Ib)
Fig. 1.35 Hypoplastic amelogenesis imperfecta with smooth enamel (type Id)
Fig. 1.36 Hypoplastic amelogenesis imperfecta with rough enamel (type If)
Fig. 1.37 Hypomature amelogenesis imperfecta (type IIb)
Fig. 1.38 Hypomineralized amelogenesis imperfecta. Autosomal fominant (type IIa)
Enamel Defects Associated with Genetic Disorders
Definition
• Many genetic disorders or syndromes may be associated, with variable incidences, with a wide variety of enamel defects. In these cases, the defect is not termed "amelogenesis imperfecta" but "enamel hypoplasia," "enamel hypocalcification," or "enamel hypomaturation," depending on the clinical features of the defects (Figs. 1.40, 1.41).
Genetic disorders
• Tricho-odonto-onychial dysplasia
• Oculodentodigital syndrome, types I and II
• Orofaciodigital syndrome (type I)
• Amelo-onychohypohidrotic dysplasia
• Ectodermal dysplasia with syndactyly
• Amelocerebrohypohidrotic syndrome
• Acrorenal ectodermal dysplasia, lipoatrophic diabetes
• Enamel renal syndrome
• Epidermolysis bullosa, dystrophic
• Focal dermal hypoplasia (Goltz syndrome)
• Hypomelanosis of Ito
• Corneodermato-osseous syndrome
• Naegeli–Franceschetti–Jadassohn syndrome
• Trichodento-osseous syndrome (types I, II, III)
• Seckel’s syndrome
• Arthrogryposis and ectodermal dysplasia
• Prader–Willi syndrome
• Singleton–Merton syndrome
• Congenital insensitivity to pain with anhydrosis
• Faciogenital dysplasia (Aarskog’s syndrome)
• Mucopolysaccharidosis IV A, B (Morquio–Ullrich syndrome)
• Lipoid proteinosis
• Mucolipidosis II (Leroy I syndrome)
• Vitamin D–dependent rickets
• Pseudohypoparathyroidism (Albright hereditary osteodystrophy)
• Tuberous sclerosis
• Pycnodysostosis
Fig. 1.39 Hypomineralized amelogenesis imperfecta. Autosomal recessive (Type IIb)
Fig. 1.40 Enamel hypoplasia in a patient with Goltz syndrome
Fig. 1.41 Enamel hypoplasia in a patient with tuberous sclerosis
Dentine Defects
Dentinogenesis Imperfecta
Definition
• Dentinogenesis imperfecta is a genetic disorder affecting dentine collagenduring embryogenesis, and particularly in the phases of tissue differentiation and organic matrix formation.
Etiology
• Dentinogenesis imperfecta can be found either isolated, characterized as type II, or as type I simultaneously with other features of osteogenesis imperfecta, a group of genetic collagen disorders characterized by anomaliesin bones, joints, eyes and teeth.
• The gene responsible for type II has been found on the 4q chromosome, whereas in type I (osteogenesis imperfecta), mutant genes have been found in chromosomes 7q and 17q.
Occurrence in children
• Type I, one per 2500–5000 (osteogenesis imperfecta).
• Type II, one per 8000.
Localization
• All teeth, primary and permanent.
Clinical features
• Striking amber translucent and discolored teeth (Fig. 1.42).
• Enamel suffering from non-accidental fractures, resulting not only from dentine defect, but also from the presence of defect in the enamel–dentine junction.
• Fragile roots and loose teeth.
• Gradual attrition or non-accidental fractures of the entire crown (Figs. 1.43, 1.44), resulting in decreased occlusal height.
• Type I may present a wide range of clinical features in the same patient, varying from easily detectable defects in all teeth, primary and permanent, to only mild pigmentation of few teeth.
• Type II shows greater uniformity, with more severe clinical features.
Radiological features
• Characteristic short roots.
• Obliteration of pulp chambers and root canals (Fig. 1.45).
• Reduced cervical diameter and radiographic contrast of dentine.
• Frequent periapical radiolucencies.
Complications
• Occlusal distortion, fragile teeth, abscesses.
Treatment
• Prosthetic rehabilitation, overdentures.
Fig. 1.42 Isolated dentinogenesis imperfecta of the primary and permanent teeth (type II)
Fig. 1.43 Dentinogenesis imperfecta (type I) of the primary teeth, revealing severe attrition in a patient with osteogenesis imperfecta type I
Fig. 1.44 Dentinogenesis imperfecta (type I) of the primary teeth, revealing less severe attrition in a patient with osteogenesis imperfecta type I (the brother of the patient in Fig. 1.43)
Fig. 1.45 Radiological features of primary and permanent molars in dentinogenesis imperfecta (type I) in a patient with osteogenesis imperfecta type I
Dentine Dysplasia
Definition
• Dentine dysplasia is usually divided into two distinct types: type I, or radicular dysplasia, and type II, or coronal dysplasia.
Etiology
• The defect results from epithelial invagination of the dental organ cells into the dental papilla, producing ectopic formation of dentine.
• The condition is transmitted an as autosomal dominant trait.
Occurrence in children
• One per 100 000.
Localization
• In both types, all teeth, primary and permanent.
Clinical features
• Type I, teeth with normal crowns of regular or slightly amber translucency. Tendency toward complete obliteration of pulp cavities. Abnormal spaces between the teeth, malalignment, malposition, and severe mobility as a result of poor root formation (Fig. 1.46).
• Type II, semi-transparent opalescent primary teeth, similar to those in dentinogenesis imperfecta, and normal clinical appearance in the permanent teeth. Incomplete obliteration of pulp cavities, particularly in the primary teeth, and frequently pulp stones (Fig. 1.47).
Radiological features
Type I
• Extremely short roots.
• Obliterated pulp chambers and root canals before eruption.
• Frequently periapical radiolucencies around the defective roots.
Type II
• Complete obliteration of pulp chambers and root canals after eruption.
• Frequently, pulp stones.
• Absence of periapical radiolucencies.
Complications
• Occlusal distortion, abscesses.
Treatment
• Prosthetic rehabilitation, overdentures.
Dentine Defects Associated with Genetic Disorders or Syndromes
Definition
• Some genetic disorders or syndromes may be associated, with variable incidences, with dentine defects. In these cases, the defect is not termed "dentinogenesis imperfecta."
Genetic disorders, syndromes
• Hypophosphatasia
• Osteogenesis imperfecta types I, III, IV (dentinogenesis imperfecta type I)
• Unger–Trott syndrome
• Vitamin D–resistant rickets
• De Toni–Debré–Fanconi syndrome
• Albright hereditary osteodystrophy (pseudohypoparathyroidism)
• Mucopolysaccharidosis III (Sanfilippo syndrome)
• Tumoral calcinosis
• Ehlers–Danlos syndrome
• Epidermal nevus syndrome
• Brachioskeletogenital (BSG)syndrome
• Dentine–osseous dysplasia
Fig. 1.46 Radiological features of radicular dentine dysplasia (type I)
Fig. 1.47 Radiological features of coronal dentine dysplasia (type II)
Defects Involving the Whole Tooth Structure
Odontodysplasia
Definition
• The term refers to a severe dental defect involving all dental tissues of both ectodermal and mesodermal origin.
Etiology
• The etiology is still unknown, although local, systemic, and genetic factors have been implicated. Recently, reports have suggested that the defect is caused by local vascular deficiency, resulting from a local developmental anatomic defect, such as a vascular nevus.
• The alteration has occasionally been associated with the epidermal nevus syndrome.
Occurrence in children
• Rare, but underreported.
• More common in females.
Localization
• Both primary and permanent dentitions are affected.
• Maxilla more frequently affected than mandible (2:1).
• The whole or part of a quadrant is involved. The defect crosses the midline in only 16% of the cases, affecting also anterior teeth.
Clinical features
• Tooth eruption is delayed and painful. Occasionally, teeth fail to erupt (Fig. 1.48).
• Frequent abscesses.
• Gingival enlargement and inflammation.
• Discolored yellow teeth with rough and small crowns and gross hypoplastic and hypocalcified enamel and dentine.
Radiological features
• Ghost-like appearance of the teeth with periapical radiolucencies (Fig. 1.49).
• Short roots with very wide pulp canals and open apices.
Complications
• Occlusal distortion, painful teeth, abscesses.
Treatment
• In cases of less affected teeth, prosthetic restoration. In severe cases, removal of the affected teeth and prosthetic rehabilitation of the involved area.
Tooth Discoloration
Definition
• Refers to color changes in the teeth.
Etiology
• The defects result from the deposition of various pigmented elements either on the enamel surface (extrinsic pigmentation) or in the inner layers of the dentine and pulp (intrinsic pigmentation).
• These defects are associated either with systemic factors and involve all the teeth, or with local factors, mainly trauma, involving certain teeth (Fig. 1.50).
Occurrence in children
• Rare.
Clinical features
Extrinsic pigments may involve all or some of the teeth, and result from an excess of various chemical elements in the saliva, which may or may not be metals, including the following (Fig. 1.51):
• Iron, magnesium, silver: black pigmentation.
• Mercury: gray or green-black pigmentation.
• Lead: gray pigmentation.
• Copper: brown or green pigmentation.
• Bromides: brown pigmentation.
• Nickel, antimony: green pigmentation.
• Cadmium: yellow pigmentation.
• Potassium: violet pigmentation.
• Enamel hypoplasia/hypocalcification: yellow-brown pigmentation.
Intrinsic pigments. This group includes the following, apart from local discoloration due to trauma:
• Erythroblastosis fetalis (incorporation of bilirubin into the developing dentition): yellow-green and blue-green color of teeth, gradually reducing with age; particularly noticeable in the anterior teeth.
• Tetracyclines (incorporation of tetracycline into the hydroxyapatite of the calcified areas of the dentine and in smaller amounts in the enamel): initially light yellow, and later a darker gray-brown color in the teeth, with horizontal bands.
• Erythropoietic porphyria, congenital (incorporation of porphyrin in developing dentition): reddish-brown or pinkish discoloration of the teeth.
• Alcaptonuria (deposition of homogentisic acid in the developing dentition): brown color of the teeth.
• Oxalosis (incorporation of oxalate crystals into the developing dentition): slate-gray discoloration of the teeth.
• Fluorosis (defective mineralization of the enamel organic matrix, resulting from defective ameloblasts during enamel maturation, due to highlevels of fluoride): chalky and opaque white or gray stains and patches (Fig. 1.52).
• Cystic fibrosis (discoloration of the teeth results from the disease alone ormedication, particularly tetracyclines): dark teeth, ranging from yellowish-grey to dark brown.
• Dentinogenesis imperfecta (genetic abnormality of the dentine collagen during the phase of histodifferentiation and organic matrix formation):brownish, semi-transparent opalescent teeth.
Treatment
• Vital and non-vital bleaching techniques.
• Conservative aesthetic restorations, prosthetic rehabilitation.
Fig. 1.48 Clinical features of regional odontodysplasia
Fig. 1.49 Radiological features of regional odontodysplasia
Fig. 1.50 Intrinsic brown pigmentation, resulting from pulpal necrosis of the primary incisor due to trauma
Fig. 1.51 Extrinsic black pigmentation, resulting from increased levels of iron in the saliva
Fig. 1.52 Intrinsic pigmentation of the permanent teeth, resulting from fluorosis
