Abnormalities of the Teeth

1. Abnormalities of the Teeth

2. Environmental Effects on Tooth Structure Development

3. Environmental Effects on Tooth Structure Development • Visible environmental enamel defects can be classified into one of three patterns: • Enamel hypoplasia – pits, grooves, or larger areas of missing enamel • Diffuse opacities of enamel – variations in translucency or normal thickness; increased white opacity with no clear boundary with adjacent normal enamel • Demarcated opacities of enamel show areas of decreased translucence, increased opacity, and a sharp boundary with adjacent enamel; normal thickness

4. Environmental Effects on Tooth Structure Development • Common pattern occurs as result of systemic influences (such as exanthematous fevers) which occur during the first two years of life; horizontal rows of pits or diminished enamel on anterior teeth and first molars; enamel loss is bilateral • Similar pattern in cuspids, bicuspids, and second molars when the inciting event occurs at age 4-5

5. Enamel Hypoplasia associated with exanthematous fevers

6. Turner’s Hypoplasia(1) • Secondary to periapical inflammatory disease of the overlying deciduous tooth • Enamel defects vary from focal areas of white, yellow or brown to extensive hypoplasia involving the entire crown. • Most frequently affects permanent bicuspids • Traumatic injury to deciduous teeth also causes Turner’s teeth (45% of children sustain injuries to primary teeth)

7. Turner’s Hypoplasia(2) • Trauma can displace the already formed hard tooth substance in relationship to the remaining soft tissue for root formation causing dilaceration (a bend in the tooth root) • Severe trauma early in tooth development can cause disorganization of the bud resembling a complex odontoma. Severe trauma later on can lead to partial or total arrest of root formation.

8. Turner’s Hypoplasia → →

9. Turner’s Hypoplasia

10. Hypoplasia Caused by Antineoplastic Therapy • Degree and severity related to age, form of therapy (chemotherapy/radiotherapy) and dose • Defects include hypodontia, microdontia, radicular hypoplasia, enamel hypoplasia and discolorations • Radiotherapy effects more severe than chemotherapy alone but sometimes used together • Dose of radiation as low as 0.72 Gy can cause mild defects in enamel/dentin • Mandibular hypoplasia due to direct radiation, alveolar deficiency or pituitary effects.

11. Hypoplasia Caused by Antineoplastic Therapy

12. Dental Fluorosis • Critical period is age 2-3, if fluoride levels greater than 1 part per million are ingested • Fluoride comes from several sources besides water: adult-strength fluoride toothpastes, fluoride supplements, infant foods, soft drinks, and fruit juices • Severity is dose dependent (higher intakes during critical periods associated with more severe fluorosis)

13. Dental Fluorosis

14. Dental fluorosis

15. Syphilitic Hypoplasia • Mulberry molars– constricted occlusal tables with disorganized surface anatomy resembling surface of a mulberry • Anterior teeth called Hutchinson’s incisors, have crowns shaped like straight-edge screwdrivers; incisal taper & notch • Treatment - Most are cosmetic problems; treatment includes acid-etched composite resin restorations, labial veneers, and full crowns

16. Hutchinson’s triad

17. Syphilitic Hypoplasia Moon’s (mulberry) molars Hutchinson’s incisors

18. Postdevelopmental Loss of Tooth Structure: Attrition • Loss of tooth structure caused by tooth-to-tooth contact during occlusion and mastication. • Pathologic when it affects appearance and function. • Process can be accelerated by poor quality or absent enamel, premature edge-to-edge occlusion, intraoral abrasives, erosion, and grinding habits.

19. Attrition • Can occur in deciduous and permanent dentitions • Most frequently, incisal and occlusal surfaces involved • Large flat wear facets found in relationship corresponding to pattern of occlusion • Interproximal contact points also affected • Over time, interproximal loss can result in shortening of arch length

20. Postdevelopmental Loss of Tooth Structure: Attrition

21. Postdevelopmental Loss of Tooth Structure: Abrasion • Pathologic loss of tooth structure secondary to the action of external agent • Most common source is tooth brushing with abrasive toothpaste and horizontal strokes. • Also pencils, toothpicks, pipe stems, bobby pins, chewing tobacco, biting thread, inappropriate use of dental floss

22. Abrasion • Variety of patterns, depending on the cause • Toothbrush abrasion presents as horizontal cervical notches on buccal surface of exposed radicular cementum and dentin; degree of loss greatest on prominent teeth • Thread-biting, pipe stem, bobby pins etc., produce rounded or V-shaped notches in incisal edges of anterior teeth • Dental floss, toothpicks result in loss of interproximal radicular cementum and dentin

23. Abrasion

24. Abrasion Abrasion from partial clasp Abrasion from improper flossing

25. Postdevelopmental Loss of Tooth Structure: Erosion • Loss of tooth structure by chemical reaction, not that associated with bacteria (caries) • Secondary to presence of acid or chelating agent • Source can be dietary (e.g., vinegar, lemons), internal (gastric secretions – perimolysis), or external (e.g., acids, industrial, atmosphere) • “If it is not abrasion or attrition, it must be erosion”

26. Erosion • Commonly affects facial surface of maxillary anteriors and appears as shallow spoon-shaped depressions in cervical portion of the crown • Posterior teeth exhibit loss of occlusal surface, where dentin is destroyed more rapidly than enamel, resulting in concave depression of dentin surrounded by elevated rim of enamel • Erosion limited to facial surfaces of maxillary anterior dentition is usually associated with dietary acid.

27. Erosion • Tooth loss confined to incisal portions of anterior dentition of both arches indicates environmental source. • Erosion on palatal surfaces of maxillary anterior teeth and occlusal surfaces of posterior teeth of both dentitions probably caused by regurgitation of gastric secretions.

28. Erosion • Fizzy Drinks Are Major Cause of Teen Tooth Erosion Thu Mar 11, 7:06 PM ET LONDON (Reuters) - Fizzy drinks are the major cause of tooth erosion in British teenagers but many parents are not aware of the problem, researchers said on Friday. • The sodas and pop drunk by up to 92 percent of UK 14-year-olds wear away the enamel protective coating on teeth. Dental erosion weakens teeth and can cause thinning or chipping of the tooth edges. • "This research identifies fizzy drink as by far the biggest factor in causing dental erosion among teenagers," said Dr Peter Rock, of Birmingham University. • "Drinking fizzy drinks only once a day was found to significantly increase a child's chances of suffering dental erosion," he added. • Drinking four or more glasses of fizzy drinks a day raises a 12-year-old's chances of suffering from tooth erosion by 252 percent. Heavy consumption in 14-year-olds increased the risk to 513 percent, according to research published in The British Dental Journal. • Unlike tooth decay, which results from high levels of sugar, erosion is caused by acidic substances in the drinks. Even diet versions are harmful. • Drinking milk and water, instead, reduces the risk. • "Erosion is a growing problem among British teenagers, yet many parents don't understand the difference between decay and erosion," said Professor Liz Kay of the British Dental Association. • "Parents need to understand...it is the acidity of certain products that cause erosion," she added in a statement.

29. Erosion

30. Postdevelopmental Loss of Tooth Structure: Abfraction • Loss of tooth structure resulting from repeated tooth (enamel & dentin) flexure produced by occlusal stresses • Disruption of chemical bonds at cervical fulcrum leads to cracked enamel that can be vulnerable to abrasion and erosion

31. Abfraction • Wedge-shaped defects limited to cervical area • Deep, narrow, V-shaped • Sometimes single tooth or subgingival • More common in mandibular dentition and among those with bruxism

32. Abfraction

33. Treatment of Postdevelopmental Loss of Tooth Structure • Early diagnosis and intervention to restrict severity of tooth loss • Patient education • Mouth guards • Limit (redirect) tooth brushing & flossing • Replacement of lost posterior teeth and avoidance of edge-to-edge occlusion • Composite resins, veneers, onlays, full crowns

34. Internal & External Resorption • Internal resorption is caused by cells located in dental pulp. Rare, usually follows injury to pulpal tissues. • External resorption is caused by cells in the periodontal ligament. Most patients are likely to have root resorption on one or more teeth.

35. Internal Resorption • Internal resorption presents as a uniform, well-circumscribed symmetrical radiolucent enlargement of pulp chamber. When it affects the coronal pulp, crown can display pink discoloration (pink tooth of Mummery)

36. External resorption • External resorption presents with a “moth-eaten” loss of root structure in which radiolucency is less well-defined and demonstrates variations in density. Most cases of external resorption involve apical or mid-portions of root

37. Internal & External Resorption • Cervical pattern of external resorption is often rapid (invasive resorption) • Multiple idiopathic root resorption – involves several teeth, underlying cause not obvious • Treatment involves the removal of all soft tissue from sites of dental destruction. For external resorption, determine if an accelerating factor is present, and eliminate it.

38. Internal & External Resorption External Resorption → → Internal resorption Internal resorption External resorption-- embedded tooth

39. Environmental Discoloration of Teeth

40. Environmental Discoloration of Teeth: Extrinsic • Arise from surface accumulation of exogenous pigment • Bacterial stains – occur most frequently in children • Excessive use of tobacco, tea, coffee • Foods that contain abundant chlorophyll • Restorative materials, especially amalgam • Medications • Stannous fluoride and chlorhexidine • Extrinsic stains can be removed by polishing with fine pumice, (sometimes with added 3% hydrogen peroxide); recurrence is likely unless the associated cause is altered

41. Environmental Discoloration of Teeth: Extrinsic Amalgam stain Tobacco stain

42. Environmental Discoloration of Teeth: Intrinsic • Secondary to endogenous factors that discolor underlying dentin • Congenital erythropoietic porphyria (Günther’s disease) is an AR disorder of metabolism that results in increased synthesis and excretion of porphyrins • Hyperbilirubinemia due to jaundice, erythroblastosis fetalis (hemolytic anemia of newborns secondary to blood incompatibility, usually Rh factor), biliary atresia (sclerosing process of the biliary tree), and chlorodontia (green discoloration).

43. Environmental Discoloration of Teeth: Intrinsic • Localized red blood cell destruction (pink discoloration arising from hemoglobin breakdown within necrotic pulp tissue when blood has accumulated in the head) • Lepromatous leprosy (pink discoloration secondary to infection-related necrosis and the rupture of numerous small blood vessels within the pulp • Medications (tetracycline) • Intrinsic stains are difficult to treat. Possible treatments include full crowns, external bleaching of vital teeth, internal bleaching of nonvital teeth, bonded restorations, composite build-ups, and laminate veneer crowns.

44. Intrinsic Coloration of Teeth Porphyria Hyperbilirubinemia Tetracycline Stain

45. Localized Disturbances in Eruption

46. Localized Disturbances in Eruption • Eruption – the continuous process of movement of a tooth from developmental location to functional location • Impacted – teeth that cease to erupt due to physical obstruction • Embedded – teeth that cease to erupt due to lack of eruptive force • Ankylosis – teeth that cease to erupt due to anatomic fusion of tooth with alveolar bone

47. Localized Disturbances in Eruption • Primary impaction of deciduous teeth is extremely rare. Most commonly involves second molars often due to ankylosis. • Primary impaction of permanent teeth most frequently affects third molars. Lack of eruption is most often related to crowding and insufficient maxillofacial development. • Impacted teeth are frequently diverted or angulated, eventually losing their potential to erupt; mesioangular, distoangular, vertical, horizontal and inverted

48. Localized Disturbances in Eruption • Treatment includes long-term observation, orthodontic-assisted eruption, transplantation, or surgical removal • Risks associated with both intervention and nonintervention • Surgical removal of impacted teeth is the procedure most frequently performed by OMFS

49. Localized Disturbances in Eruption • Ankylosis – cessation of eruption after emergence • Usually develops between ages 7-18; peak 8-9; prevalence est. 1.3-8.9% • Fails to respond to orthodontic therapy • Failure to treat can result in tilting, carious destruction, and periodontal disease • When successor tooth present, best treated with extraction and space maintenance

50. Localized Disturbances in Eruption Primary tooth impaction Mesioangular impaction Ankylosis