Noncarious Diseases of Teeth Hard Tissues The Classification of Noncarious Diseases of Teeth Depending on their origination period the noncarious diseases of teeth hard tissues are divided into two basic groups (V.Patrikeev, 1986): 1. Diseases of teeth hard tissues, which are originated during a tooth development or before the tooth eruption a) Enamel hypoplasia b) Enamel hyperplasia c) Dental fluorosis d) Hereditary disturbances of the tooth development 2. Diseases of teeth hard tissues, which are originated after the tooth eruption a) Tooth discoloration and dental plaques b) Tooth wear, attrition, abrasion c) Abfraction d) Dental erosion e) Dental necrosis f) Tooth traumas f) Dental sensitivity Classification of Noncarious Diseases of Teeth Hard Tissues accepted by WHO in 1997 I Disorders of Tooth Development and Eruption 1. Anomalies of the tooth dimensions and shape- teeth coalescence, fused teeth, splited teeth, enamel drop (nodule, pearl), tooth in tooth. 2. Stained teeth- dental fluorosis 3. Teeth forming disorders- enamel hypoplasia (prenatal and neonatal, Terner’s teeth). 4. Hereditary disorders of teeth structures - indefinite amelo- and dentinogenesis, teeth changes because of indefinite osteogenesis. 5. Congenital syphilitic symptoms: screwdriver molars, Hutchinson’s teeth. 6. Other disorders of tooth development: color changes which are caused by Rh-conflict, congenital anomalies of the biliary system, porphyria and tetracycline usage in big quantities. II Other Diseases of Teeth Hard Tissues 1. Tooth wear 2. Abrasion ( loss by wear of dental tissue, caused by abrasion by foreign substance e.g., toothbrush with tooth powder; abfraction because of bad habits, harmful professional materials and habits influences) 3. Dental erosion: professional, idiopathic, are conditioned by diet, medicaments and vomiting. 4. Dental calculi: colored plaque (dark, green, orange and plaque which is conditioned by smoking and betel chewing) generalized soft plaque, white deposit (materia alba), supra- and subgingival calculi. 5. Teeth hard tissues’ discoloration after eruption, caused by metals, presence of metal combinations, pulp bleeding, any habits which may be contributing to the condition, including tobacco use. 6. Other Specified Diseases of Teeth Hard Tissues: hypersensitive dentin, enamel changes, which are caused by the irradiation III Destructions, poisonings and other after-effects, caused by the influence of external factors 1. Tooth fracture 1.1. Tooth enamel fracture 1.2. Crown fracture without a pulp trauma 1.3. Crown fracture with exposed pulp 1.4. Root fracture 1.5. Crown and root fracture 1.6. Multiple fractures of tooth 2. Tooth dislocation: luxation, extrusion or intrusion, exarticulation 1 Enamel Hypoplasia Enamel hypoplasia (EH) is a tooth enamel defect that results in lessening of the quantity of enamel. The defect can be a small pit or dent on the tooth, or can be so widespread that the entire tooth is small and/or misshaped. A critical manifestation of the hypoplasia is the aplasia, i.e. a congenital absence of the enamel or the tooth. Etiology and pathogenesis: Hypoplasia is caused by metabolic processes disturbances in the teeth embryos. This can be occurred under the influence of mineral and albuminous exchange disturbances in embryos or child organism, or local reasons, influencing on the teeth embryos. When enameloblasts development is affected only, enamel hypoplasia is occurred, but when odontoblasts metabolism is also affected, the enamel hypoplasia is accompanied by dentin formation disturbances. Some scientists think that hypoplasia is caused, because of the enameloblasts formation disturbance (A. Abrikosov, 1914). According to the point of view of another group of scientists (I. Lukomsky, 1953, S. Vays, 1965), hypoplasia is a defect of the tooth tissues mineralization, in case of their proper forming. Z. Sharaevskaja (1954), I. Novikov (1961), A. Ribakov 1961) point out, that these two processes are interconnected. They think that teeth hard tissues’ hypoplasia is caused by both: disturbance of the enamel formation by ameloblasts and the suppression of the mineralization of the enamel prisms. Hypoplasia origination causes: a) Local harmful affect on the tooth embryo b) Metabolic disturbances in an embryo’s or a child’s organism during rachitis, infectious diseases, dyspepsia, functional disorders of the endocrine glands, etc. During hypoplasia the enamel changes are irreversible. Hypoplasia of primary teeth is mainly connected with the disorders in pregnant woman’s organism (toxicosis, etc). Hypoplasia of primary teeth is found rarely than hypoplasia of permanent teeth, which is connected with metabolic disorders in children’s organism. Hypoplasia of permanent teeth is caused by different diseases children have during the teeth formation and mineralization: rachitis, acute infectious diseases, diseases of gastroenteric path, toxic dyspepsia, alimentary dystrophy, disorders of endocrine system, congenital syphilis, cerebral disorders, etc. The location of the hypoplasia on the tooth crown and the extension of damage depend on the age of the child, when he/she undergone mentioned diseases. For example, in case of the diseases during first months after birth the incisal edges of the incisors and the cusps of the molars are affected. The size of the affected area indicates the long duration of the disease. Classification: According to the etiological factors there are systemic and local hypoplasias. Systemic hypoplasia is noted at teeth, which are formed at the same period. The hypoplasia of one tooth is called local. Systemic hypoplasia: Clinically 3 types of systemic hypoplasia are distinguished: - change of the enamel color - enamel underdevelopment - enamel absence Clinical symptoms The enamel color change is displayed as white or yellow spots, which have precise verges and the same size. The spots are usually found out on the vestibular surface of the teeth and aren’t accompanied by hypersensitivity. During the lifetime the size, the form and the color of the spot isn’t changed. Enamel underdevelopment is the maximal severe form of the systemic hypoplasia. It can appear with wavy (rough), spotted (pitted) or grooved surface. Wavy enamel is appeared after drying the crown surface with cylinders shape. There is unchanged enamel between cylinders in looks of the pits. The spotted changes of enamel are located on the both oral and vestibular tooth surfaces and have natural color after tooth eruption. These spots change the color later, though the enamel is still strong and smooth. This is the most widespread type of the hypoplasia. The grooved surface gives evidence of the isolated or multiple grooves on the tooth surface. If the whole crown has a lot of grooves it is called a “stepped”. In all the above stated examples the wholeness of the enamel isn’t broken. 2 The absence of enamel or aplasia is the most severe type of the hypoplasia and it is rarely met. In this case apart from the aesthetic defects the feeling of the pain can be present because of the irritant affect. The pain is eliminated after the stimuli removing. The Hutchinson’s, Furner’s and Pfluger’s teeth are the variety of the systemic hypoplasia. Hutchinson’s teeth (screw-driver, notched teeth): the teeth of congenital syphilis in which the incisal edge is notched and narrower than the cervical area. Furner’s teeth are the same with Hutchinson’s teeth without half-moon notches. They occur because of the congenital syphilis and smallpox. Pfluger’s teeth are the first molars, with the conic crown shape (the cervical area is wider than occlusal surface) and have under developmental cusps. “Tetracycline” teeth: This is a type of the systemic hypoplasia. Tetracycline is an antibiotic. It's a fairly powerful antibiotic that kills a broad spectrum of bacteria. However, when it is taken while teeth are forming, it deposits in the dentin and enamel of the teeth and creates a permanent gray or brown stain. It can be a uniform discoloration of the entire tooth or can occur in the form of horizontal bands of stain of varying intensity. They can range from mild to very dark. As a result, tetracycline is forbidden for pregnant women, because it can penetrate through the placenta. A tetracycline tooth stain is irreversible. That’s why tetracycline should be appointed for children and pregnant women only if it is necessary for life. Local hypoplasia is the defective or incomplete development of the enamel. Local hypoplasia of permanent teeth can be a result of injury or inflammation of the precedent primary tooth. Clinical symptoms It is characterized by pits and chalky spots (of color from white to brown) on the entire tooth surface. Sometimes it happens that all enamel or a part of it is missing. These teeth are called Turner’s teeth. More often the local hypoplasia is met on the premolars, which embryos are located between primary teeth (between primary incisors and canines, which are affected by caries and periodontitis very often). Pathological anatomy During histological investigations the decreasing of the enamel width, widen interprismal spaces, a smoothing prisms’ borders, a widening of the calcification lines of Retzius etc. are found. On the spotted type the changes of the dentin occur as well. In this case the interglobular spaces are increasing, the intensive producing of the secondary dentin in the pulp is formed and the quantity of the cells is being reduced. Differential diagnosis Enamel hypoplasia should be differentiated from