Anomalies of Teeth PDF

# Anomalies of Teeth ## Alterations in Size ### Microdontia - **Generalized Microdontia:** - All teeth appear smaller than normal such as in pituitary dwarfism. - May appear small in relation to large mandible and maxilla. - **Localized Microdontia:** - A single tooth is smaller tha...

# Anomalies of Teeth ## Alterations in Size ### Microdontia - **Generalized Microdontia:** - All teeth appear smaller than normal such as in pituitary dwarfism. - May appear small in relation to large mandible and maxilla. - **Localized Microdontia:** - A single tooth is smaller than normal. - Shape is also altered along with size eg. Peg lateral and maxillary third molar and supernumerary teeth. A picture of a child's opened mouth revealing its teeth is included. The child suffers from microdontia. All teeth appear smaller. A picture of a person's side profile showing the inside of their mouth, as well as their left lower canine and incisor teeth, is included. The left central incisor appears smaller and more pointed than the rest of the teeth. ### Macrodontia - **Generalized Macrodontia:** - Appearance of enlarged teeth eg. In pituitary gigantism. - Also teeth may appear to look enlarged due to small maxilla and mandible. This could lead to overcrowding and abnormal eruption pattern due to insufficient space. - **Localized Macrodontia:** - Abnormality to a tooth where it appears abnormally large. Usually seen with third molars. A picture of a person’s opened mouth with teeth showing is included. The left central incisor appears larger than the rest of the teeth. One picture below shows the person's smile in a close-up, and the other picture is a black and white x-ray of their teeth. ## Alterations in Shape ### Gemination - Fusion of two teeth from a single enamel organ. - Two crowns sharing the same root canal with partial cleavage. - Complete cleavage results in two teeth from one tooth germ ### Fusion - Joining of two developing tooth germs, resulting in a single large tooth structure. - Fusion process may involve the entire length of the teeth or may involve the roots only, in which cementum and dentin are shared. - Root canals may be separate or shared. Two tooth shapes are drawn, one representing gemination and the other representing fusion. Both are side profiles. A picture of a tooth is included. The tooth is held by a gloved hand, and in black and white. An x-ray of a similar tooth is included alongside the picture. ### Concrescence - Form of fusion in which adjacent teeth are joined by cementum, resulting in one singular tooth. - Commonly seen with maxillary second and third molars Two pictures of teeth are included; both are side profiles. The top one shows the teeth joined by cementum. ### Dilaceration - Extraordinary curving or angulation of tooth roots. - Extractions and RCT are challenging. A picture of a tooth is included; it's a side profile view, showing the roots. It's curved at the top and then straight with another curve at the bottom. ### Dens Invaginatus - Also known as dens in dente or tooth within a tooth. - Uncommon. - Represented as an exaggerated lingual pit. - Can affect only the crown and also crown and root. - Maxillary lateral incisors are commonly involved. - Involvement bilaterally is often seen. Two pictures are shown, both containing close-ups of the inside of a person's mouth, highlighting the teeth on the left side. One picture is an x-ray, taken from the outside of the mouth. Two x-rays are shown. One is a side-profile view of the left end of a person's mouth. The other is a close-up view of the same area. ### Dens Evaginatus - Common condition. - Frequently bilateral. - Anomalous tubercle or cusp located in the center of the occlusal surface. A picture of a person's opened mouth revealing its teeth is included. The lower left molar has a small bump in the middle of the tooth. ## Taurodontism - **Definition:** Taurodontism is morphoanatomical change in the shape of a tooth, which usually occurs in multirooted teeth. It is characterized by an enlarged body and pulp chamber as well as apical displacement of the pulpal floor. - The term means “bull like” teeth. On dental radiograph, the involved tooth looks rectangular in shape without apical taper. The pulp chamber is extremely large and the furcation may be only a few millimeters long at times. Two pictures of x-rays of teeth are included. One is of a person’s upper teeth, and the second one is a close-up of two bottom teeth, showing the pulp chamber. ## Supernumerary Teeth - Extra teeth in the dentition. - Commonly results from continued proliferation of the dental lamina to form a third tooth germ. - More in permanent than in primary dentition. - Anterior midline is the most common site (mesiodens). - Maxillary molar area (fourth molar) is the second most common site. - Appearing at the time of birth (natal teeth). ## Supernumerary - Most commonly seen in canines, premolars and molars (esp 3rd). - Clinically important when doing extractions and RCT. A picture of a person’s open mouth, with all teeth visible, is included. Each tooth appears to be in its appropriate place. ## Enamel Pearls - Ectopic enamel found on the roots of the teeth. - Most commonly occur at the furcation area. - Supported by dentine but pulp does not extend into it. - Important in periodontal aspect. - Maxillary molars are more commonly affected than mandibular. Two pictures of teeth are included. Both are side profile views. The left one shows the root of the tooth, with one enamel pearl on the root of the tooth, and the other shows two enamel pearls on the root of the tooth. ## Attrition, Abrasion and Erosion - **Attrition:** Physiologic wearing of teeth resulting from mastication. - **Abrasion:** Pathologic wearing of teeth as a result of an abnormal habit or abnormal use of abrasive substances. - **Erosion:** Loss of tooth structure from a nonbacterial process. - Acids are often involved in the dissolution process. External sources include work environment, or diet. Internal sources are from gastrointestinal reflux or vomitting (bulimia and anorexia). **Difference between dental attrition, abfraction, erosion and abrasion** - **Attrition:** Teeth appear worn down. - **Abfraction:** Teeth appear chipped at the gum line. - **Erosion:** Teeth appear worn down and translucent. - **Abrasion:** Teeth appear worn down and rough. ## Non carious Loss of the Tooth Structure due to Attrition, Abrasion, Abfraction and Erosion - **Attrition:** Mechanical wear between opposing teeth commonly due to excessive masticatory forces. - **Abrasion:** Loss of tooth material by mechanical means other than by opposing teeth. - **Erosion:** Loss of dental hard tissue as a result of a chemical process not involving bacteria. - **Abfraction:** Abfractions are the microfractures which appear in the enamel and possibly the dentine caused by flexion of the cervical area of the tooth under heavy loads. Abfraction lesions usually appear as wedge-shaped defects with sharp line angles. ## Alterations in Number ### Anodontia - Absence of teeth. - Classified as: - **Complete anodontia:** When all teeth are missing - **Partial anodontia:** When one or few teeth are missing. - **Pseudoanodontia:** When teeth are clinically absent due to impaction or delayed eruption of teeth. - **False anodontia:** Teeth have exfoliated or been extracted. - Partial anodontia is common with third molars, followed by second premolars and maxillary laterals (congenitally missing). - Complete anodontia is associated with ectodermal dysplasia. A picture of a child's opened mouth revealing its teeth is included. The child suffers from a missing two front teeth. ## Impaction - Common especially to third molars and maxillary canines. - Due to overcrowding or some other physical barrier. - Unusual orientation of the tooth germ. - Fusion of bone around tooth (ankylosis). A graphic with a diagram of a tooth is included. The tooth is embedded in the jaw. ## Defects of Enamel ### Environmental Defects of Enamel - During enamel formation ameloblasts are susceptible to various external factors. - Quantitavely defective enamel when of normal hardness (Enamel hypoplasia). - Qualitatively defective enamel where normal amount is produced but is hypomineralized (Enamel hypocalcification). A picture of a person's opened mouth revealing its teeth is included. The photo is taken from a side view and shows the lower molars of this person. Two arrows point at areas of enamel hypoplasia. - **What causes enamel hypoplasia?** - Intensity of etiologic factor. - Duration of factor’s presence. - Time at which the factor occurs during crown development. - Local trauma or abscess formation can adversely affect ameloblasts. - Affected teeth may have areas of discoloration or may have actual irregularities. - Results in Turner’s tooth. - **Turner’s Hypoplasia:** Enamel defects seen in permanent teeth is caused by periapical inflammatory disease of the overlying deciduous tooth. The altered tooth is called a Turner’s tooth. A picture of a person's opened mouth revealing its teeth is included. The photo is taken from a side view and shows the left lower molar. An arrow points at the area of affected enamel. A black and white x-ray of the same tooth is included. - **Anterior teeth are involved less frequently because crown formation is usually complete before the development of any apical inflammatory disease.** - **Extensive enamel hypoplasia of mandibular first bicuspid secondary to previous inflammatory process associated with overlying first deciduous molar.** - **In order for systemic factors to have an effect on developing teeth, they must generally occur after birth and before the age of six.** - **Systemically induced enamel defects are seen to be of an attribution from childhood infectious disease.** - **Other cited causes of enamel hypoplasia and hypocalcification include nutritional defects such as rickets, congenital syphilis, birth trauma, fluoride and idiopathic factors.** - **In congenital syphilis, utero infection by Trepenoma pallidium affects incisors and molars.** - **Hutchinson’s incisors:** Tapered incisally, notched centrally on the incisal edge. - **Mulberry molars:** Lobulated or crenated occlusal surface. - **Fluorosis (hypocalcification):** Caused by drinking water greater levels of fluoride than normal during the time crowns are being formed. - **Ranges from mild to severe whereby it may appear as mild as white spots, and severe as pitted, irregular and discolored enamel.** - **Amelogenesis Imperfecta:** Group of similar appearing hereditary disorders of enamel formation in both dentitions. - Either hypoplastic or hypocalcified or hypermaturation. - **Hypoplastic teeth:** Insufficient amounts of enamel ranging from pits and grooves to complete absence. - **Hypocalcified teeth:** Quantity of enamel is normal but it is soft and friable. Color ranges from each tooth and patient from white opaque to yellow to brown. A picture of a person's opened mouth revealing its teeth is included. The photo is taken from a side view and shows the lower incisors of this person. ## Defects of Dentine ### Dentinogenesis Imperfecta - Autosomal dominant trait. - Affects dentine of primary and permanent dentitions. - Also known as opalescent dentine. - **Three types:** - **Type 1:** Dentin abnormality occurs with osteogenesis imperfecta. Primary teeth are more affected. - **Type II:** No bone disease. - **Type III:** Similar to type II but with some clinical and radiographic variations. - Share some common features such as: - Exhibit an unusual translucent, opalescent, with color varying from yellow to gray. - Entire crown looks discolored. - Enamel fractures easily. - Excessive constriction at the CEJ giving crowns a tulip or bell shape. - Radiographically, types I and II exhibit identical changes with opacification of pulp, short roots, bell shaped crowns. - **Type III:** Dentine appears thin and pulp and root canal large giving the appearance as shell teeth. - There are few but larger dentinal tubules in dentinogenesis imperfecta. Also there is irregular dentine deposition which replaces the pulpal space and there is no scalloped junction. ### Dentine Dysplasia - Rare autosomal dominant trait that affects dentine. - **Type I:** Radicular type. - **Type II.** Coronal type. - Difference of the above two being that type II color of the primary dentition is opalescent and permanent is normal, coronal pulps are quite large and filled with globules of dentine and hardly any periapical lesions where as in type i both dentitions are, the color is normal and there are periapical lesions. - **Clinically in type I, crowns appear to be normal. Premature loss may occur as there are short roots or PA lesions.** - **Radiographically, type I roots are short with obliterated pulps.** - **In type II, pulp chambers exhibit to be enlarged.** - **Microscopically deeper layer of dentine show atypical tubular patterns with amorphous, and irregular organization.** ## Defects of Enamel and Dentine ### Regional Odontodysplasia - Dental abnormality that involves the hard tissues that are derived from both epithelial and mesenchymal components affecting enamel, dentine and cementum. - Affected to the extent that they exhibit short roots, open apical foramina and enlarged pulp chambers. - Thinnest and poor mineralization quality of the enamel and dentine gives rise to ghost teeth. - Permanent teeth are more affected than primary. - Maxillary anterior teeth more affected. - Eruption is delayed. ## Abnormalities of Dental Pulp ### Pulp Calcification - Common with increasing age. - May be microscopic in size or large enough to be detected radiographically. - Calcifications maybe linear or nodular (pulp stones). - When composed of dentine - true denticles. - Represent foci of dystrophic calcification - false denticles. - Subdivided into attached and free types. ## Internal Resorption - Resorption of dentine of the pulpal walls as a reaction to pulpal injury or no trigger. - Occurs as a result of activation of osteoclasts or dentinoclasts on internal surfaces of the root or crown. - Resorption lacunae are seen. - Reversal lines may also be seen in the adjacent hard tissue indicating attempts at repair. - Perforation can occur. - Teeth may appear pink. ## External Resorption - Several causes such as: - Chronic inflammatory lesion. - Cysts. - Benign tumors. - Malignant neoplasms. - Trauma. - Reimplantation. - Impactions. - Seen to be due to release of chemical mediators, increased vascularity and pressure. - Occurs immediately apical to the CEJ. - Lesions occurring on the root surface below the gingival epithelial attachment. - Starts at the tooth apex and progresses occlusally. ## Alterations in Color ### Exogenous Stains - Stains that can be removed with abrasives. - Caused from diet or by products from bacteria. ### Endogenous Stains - Deposits of systemically circulating substances during tooth development gives rise to endogenous staining. - Systemic ingestion of tetracycline during tooth development. Yellow in colour. - With it changes from yellow to gray to brown. - **Rh incompatibility:** Caused by red cell haemolysis. Blood breakdown products are deposited in developing primary teeth. - **Appear green to brown.** - **Congenital porphyria deposition:** Teeth may appear red to brown due to deposition of porphyrin in the developing teeth. - **Liver disease, biliary atresia and neonatal hepatitis.**