Physical And Chemical Injuries Of Oral Tissues Question And Answers

Physical And Chemical Injuries Of Oral Tissues Pathology Question And Answers

Question 1. Name the common non-traumatic causes of tooth fracture.
Answer.

• Caries
• Tooth weakened by a large restoration
• Non-vital tooth
• Internal resorptions.

Question 2. What is class I fracture of tooth?
Answer. Class I tooth fracture is the simple fracture of crown of tooth that involves enamel with little or no dentin involvement.

Question 3. What is class II fracture of tooth?
Answer. It is the fracture of tooth which involves the enamel and dentin but not the pulp.

Question 4. In the classifiation of tooth fracture, what does class III fracture means?
Answer. Class III tooth fracture means extensive fracture involving considerable dentin with exposure of pulp.

Question 5. What is class IV fracture of tooth?
Answer. When the fracture causes loss of vitality of the affected tooth it is called class IV fracture.

Question 5a. What color a non-vital tooth often has?
Answer. Gray color.

Question 5b. What produces the gray color in a non-vital tooth?
Answer. In a non-vital tooth, necrosis of blood releases biliverdin and as the later molecules diffuse into the dentinal tubules the tooth looks gray.

Question 6. What is class V fracture of tooth?
Answer. It is the fracture which causes complete loss of the affected tooth.

Question 7. What type of fracture it is, if a tooth fracture involves the root with or without the crown?
Answer. It is a class VI fracture.

Question 8. What is class VII fracture of tooth?
Answer. Class VII fracture presents displacement of the affected tooth without any fracture of the crown or the root.

Question 9. What is class VIII fracture of tooth?
Answer. Class VIII is the fracture of the tooth crown en mass and its replacement.

Question 10. Describe class IX fracture of tooth.
Answer. When the fracture involves the deciduous teeth it is called class IX fracture.

Question 11. Which type of malocclusion is associated with higher rates of tooth fracture?
Answer. Class II malocclusion.

Read And Learn More: Oral Pathology Short Notes Question And Answers

Question 12. What is the commonest cause of root fracture of tooth?
Answer. Trauma.

Question 13. What is the common age of root fracture of tooth?
Answer. Between the ages of 10 and 20 years.

Question 14. What is the most common type of root fracture of tooth?
Answer. Most of the root fractures are horizontal in nature and are located in the middle third of the root.

Question 15. What is cemental tear?
Answer. Cemental tear refers to small fracture with subsequent detachment of cementum on the root surface of tooth, which results in presence of isolated tiny mass of cemental tissue within the periodontal ligament.

Question 16. What is the usual cause of cemental tear?
Answer. It usually occurs as a result of sudden rotational forces in the tooth.

Question 17. How the tooth clinically behaves in case of cemental tear?
Answer. The tooth clinically remains asymptomatic.

Question 18. What is cracked-tooth syndrome?
Answer. Sometimes, in cases of vertical tooth fracture, patients often complain of a sharp pain especially during chewing hard foods but the fracture is not detected by radiographs and this condition is often known as the cracked-tooth syndrome.

Question 19. What is the treatment of cracked-tooth syndrome?
Answer. Extraction of the affected tooth.

Question 20. Name the common diseases associated with premature tooth loss.
Answer.

• Trauma
• Dental caries
• Radiotherapy
• Aggressive juvenile periodontitis
• Diabetes mellitus
• Histiocytosis X
• Hypophosphatasia
• Vitamin C defiiency
• HIV/AIDS
• Chemotherapy.

Question 20a. What does Battle’s sign mean?
Answer. Ecchymosis of the mastoid region.

Question 20b. What is the most important protective response of pulp to sublethal injures?
Answer. Formation of reparative dentin.

Question 21. What is bruxism?
Answer. Bruxism can be defied as the habitual, unintentional grinding or clenching of teeth, which the patient does periodically either during sleep in the night or during daytime.

Question 22. What is the most embarrassing thing about bruxism?
Answer. The person who has the habit of bruxism does grinding or clenching of teeth at inappropriate moments along with repeated tapping.

Question 23. Name the various causes of bruxism.
Answer.

• Local cause
• Systemic cause
• Psychological cause
• Occupational cause
• Habitual cause.

Question 23a. What is the most important and probable cause of bruxism among all?
Answer. Psychological cause.

Question 24. What is the local cause of bruxism?
Answer. Occlusal disturbances.

Question 25. Name the systemic causes of bruxism.
Answer.

• Chronic GI upset
• Sleep disorder
• Heredity
• Physical disability
• Endocrine disorder.

Question 26. Name the psychological states often associated with bruxism.
Answer.

• Emotional upsets due to fear, pain, anger, rejection, nervousness or frustrations
• Persons with aggressive, hurried or overly competitive behavior.

Question 27. Name the types of bruxism.
Answer. There are two types of bruxism—Nocturnal and daytime habit (Nocturnal means–happening or done by night).

Question 28. What are the clinical features of bruxism?
Answer.

• Severe attrition and loosening of teeth with gingival recession
• Tapping noise during grinding of teeth
• Tooth sensitivity
• Trismus
• Facial pain with headache
• A popping or clicking sound in the TM Joint
• Intraoral erosion of buccal mucosa.

Question 29. What is concussion of tooth?
Answer. Concussion occurs following minor injury to the tooth, which is not strong enough to cause any serious visible damage; the only feeling patient can have in the tooth is increased sensitivity to percussion from any direction.

Question 30. What is subluxation of tooth?
Answer. It refers to abnormal loosening of tooth without displacement due to sudden trauma.

Question 31. What are the clinical features of subluxation of tooth?
Answer.

• Tooth mobility
• Sensitivity to percussion
• Bleeding from the gingival crevice.

Question 32. What is the common fate of the affected tooth in subluxation?
Answer. The tooth gradually losses its vitality due to severance of apical nutrient vessel.

Bilirubin

Question 33. What is ankylosis of tooth?
Answer. Tooth ankylosis is a pathological condition in which the root of the tooth becomes completely fused with the bony socket.

Question 34. How ankylosis of tooth occurs?
Answer. In case of ankylosis, the soft tissue separation between root of tooth and the alveolar bone (periodontal ligament) is lost and as a result the tooth becomes united with the jawbone. The process starts due to partial resorption of the root due to some reason, which is later on repaired by deposition of cementum or alveolar bone eventually resulting in obliteration of periodontal ligament space with bony fusion of root.

Question 34a. Name the most important pre-condition for tooth ankylosis.
Answer. Resorption of tooth root

Question 35. Name causes of ankylosis of tooth.
Answer.

• Heredity
• Occlusal trauma
• Chronic periodontal or periapical inflmmation
• Sports injury or accident of teeth
• Problems with mineral metabolism or bone growth
• Reimplantation or transplantation of teeth
• Idiopathic.

Question 35a. What are the consequences of ankylosis of tooth?
Answer. Many of these teeth fail to erupt in the oral cavity, moreover, teeth which erupt are diffiult to extract because of the bony union.

Question 36. Which dentition is affected in case of ankylosis?
Answer. Ankylosis can occur in both deciduous as well as in permanent dentitions.

Bilirubin

Question 37. Does ankylosis produce any clinical symptoms?
Answer. The ankylosed teeth usually do not exhibit any clinical manifestations; however, they often produce a dull, high pitched, muffld sound on percussion, instead of a sharp normal sound.

Question 38. What is the signifiance of ankylosis in a deciduous tooth?
Answer. Ankylosed deciduous tooth doesn’t exfoliate spontaneously and it often blocks the path of eruption of permanent tooth.

Question 39. Name the complications which might arise due to ankylosis of tooth.
Answer.

• Malocclusion of teeth especially infraocclusion
• Abnormal tooth eruption pattern in the jaw
• Periodontal problems
• Dental caries
• Facial skeletal deformity.

Question 40. Describe the radiological features of tooth ankylosis.
Answer. Radiographically ankylosed tooth often exhibits obliteration of periodontal ligament space around the root.

Question 41. What are the treatment options possible for an ankylosed tooth?
Answer.

• Orthodontic treatment to help the tooth to erupt
• Surgical repositioning of the affected tooth
• If required the tooth should be extracted by surgical method only.

Question 42. What is a submerged tooth?
Answer. It is a disorder of eruption, in which a tooth has failed to erupt to the point of making contact with the tooth of opposing arch.

Question 42a. Which tooth is generally affected by the phenomenon of submerged tooth?
Answer. Submerged teeth are mostly ankylosed deciduous teeth, usually located in the mandibular posterior region.

Question 43. Name the causes of development of submerged tooth.
Answer.

• Genetic cause
• Congenital developmental gap in the periodontal ligament
• Trauma
• Excessive mechanical force
• Disturbed local metabolism
• Congenital absence of permanent successor.

Question 44. What is toothbrush injury?
Answer. Toothbrush injuries are caused by chronic physical irritation from the toothbrush bristles to the marginal and the attached gingiva.

Question 45. Which part of the oral cavity is more often affected by toothbrush injury?
Answer. These injuries occur more often in the maxillary gingiva over the premolar and canine region (since these are the locations where maximum pressure is exerted during brushing).

Question 46. Describe the clinical appearance of toothbrush injury in the mouth.
Answer. The lesions commonly appear as painful superfiial linear erosions in an erythematous background; some lesions may appear as white, red or ulcerated areas or even deep clefts in the gingiva.

Question 47. Describe the effects of tooth-prick injury in tooth and related structures.
Answer.

• Development of a depression in the buccal and lingual aspects of gingiva
• Gingival recession
• Increased interproximal space between teeth with food impaction
• Damage of cementum, cervical enamel and dentin.

Question 48. What is traumatic atrophic glossitis?
Answer. These are focal sensitive erythematous areas of the tongue caused by physical (traumatic) injury or irritation.

Question 49. Name the causes of chronic ulcerations in the tongue.
Answer.

• Trauma
• Psychologic stress
• Functional abnormality of tongue
• Medications e.g. lansoprazole and mouth washes
• Malnutrition
• Systemic diseases e.g. diabetes, parkinsonism and malignancy
• Hematological factor e.g. iron defiiency or aplastic anemia, and agranulocytosis
• Oral habits e.g tobacco
• Infections e.g. tuberculosis, HIV infection and candidiasis
• Immunologic abnormality e.g. aphthous ulcer
• Factitious injury.

Question 49a. In which part of the oral cavity inflmmatory papillary hyperplasia often occurs?
Answer. Palate.

Question 50. What are factitious injuries?
Answer. Factitious injuries are self-inflcted injuries caused by the patient himself or herself and these are either habitual or inadvertent.

Question 51. Why patients create factitious injuries to themselves?
Answer. These injuries are commonly seen in persons with disturbed mental state and who purposefully create these injuries for seeking attention.

Question 52. Give common types of factitious injuries in the orofacial region.
Answer.

• Cheek and lip biting
• Self extraction of tooth
• Fingernail injuries
• Nasal ulcerations and facial emphysema
• Periorbital ecchymoses
• Persistent oral mucosal and gingival ulcerations
• Mandibular sublaxation.

Question 53. What are the distinct characteristics of a factitious injury?
Answer.

• Presence of a wound in absence of any recognizable disease or any justifid reason
• Bizarre shape or outline of the wound not corroborating to the history as given by patient
• Wounds found in the mouth of an otherwise healthy individual
• Wounds present in areas of mouth easily accessible to patient
• Clinical appearance of the wound is often inconsistent with the history given by the patient.

Question 54. Name the common denture related injuries in the mouth.
Answer.

• Traumatic ulcer
• Denture hyperplasia
• Denture stomatitis or sore mouth
• Angular stomatitis (due to improper vertical height in dentures)
• Papillary palatal hyperplasia
• Frictional keratosis
• Pain due to pressure on a buried tooth in the gums.

Question 54a. What is epulis fisuratum?
Answer. It is a type of denture hyperplasia which occurs due to chronic mechanical irritation caused by the flnge or border of an ill-fiting denture.

Question 54b. What are the other names of epulis fisuratum?
Answer. Denture-induced firous inflmmatory hyperplasia, denture epulis or granuloma fisuratum, etc.

Question 54c. What is palatal papillomatosis?
Answer. It is a denture hyperplasia characterized by multiple closely arranged papules on the palatal mucosa underlying an ill-fiting denture.

Question 55. What is linea alba?
Answer. Linea alba or white line is a common alteration of the buccal mucosa which is probably caused by pressure, friction or sucking trauma from the facial surfaces of teeth.

Question 56. What is the clinical appearance of linea alba?
Answer. It appears as bilateral white line on the buccal mucosa at the level of the occlusal plane of the adjacent teeth.

Question 57. What is morsicatio buccarum?
Answer. Morsicatio buccarum is the scientifi term for chronic cheek biting or chewing.

Question 58. Describe the clinical appearance of the lesion caused by chronic cheek biting.
Answer. It produces bilateral, thick, shredded, white areas on the anterior buccal mucosa with ragged surface.

Question 59. What is the clinical appearance of a traumatic ulcer of mouth?
Answer. It presents an erythematous area surrounding a central movable, yellow firinopurulent membrane.

Question 60. How the borders of a traumatic ulcer appear?
Answer. Traumatic ulcers often have a rolled white border of hyperkeratosis.

Question 61. What is the most important characteristic of a traumatic ulcer?
Answer. In most of the cases, there is presence of a source of irritation or injury, immediately adjacent to the ulcer.

Question 62. Which lesion traumatic ulcer often clinically resembles to?
Answer. Early ulcerative squamous cell carcinoma.

Question 63. What is Riga-Fede disease?
Answer. It is the traumatic ulcer of mouth in newborns produced generally by irritation from natal or neonatal tooth mostly during breastfeeding.

Question 64. What is the usual age of occurrence of Riga-Fede disease?
Answer. The condition develops between 1 week and 1 year of age.

Question 65. Which part of the mouth is often affected in Riga-Fede disease?
Answer. Tongue is mostly affected either in the ventral or in the dorsal surface; ulcers on the ventral surface are caused by irritation from lower anterior teeth, while ulcers on the dorsal surface are caused by upper anterior teeth.

Question 66. What is electrical burn?
Answer. It is the deep thermal burn in the mouth caused by contact with a live electrical wire.

Question 67. How electrical burns in the mouth occur?
Answer.

• Due to biting on the plugged cord of an electrical appliance by the child
• Sucking on the receptacle end of an extension cord.

Question 68. What are the types of electrical burn?
Answer. Electrical burns can be of two types—contact burn and arc burn.

Question 69. What is contact electrical burn?
Answer. Contact electrical burn occurs when electrical current passes through the body from a point of contact into the ground.

Question 70. What is arc electrical burn?
Answer. Arc electrical burn occurs when an electrical arc flws between the electrical source and the mouth, in which saliva acts as a conducting medium.

Question 71. Which type of electrical burn is more prevalent in the oral cavity?
Answer. Electrical burns in the oral cavity are mostly arc type.

Question 72. Why severe tissue damage occurs in electrical burns?
Answer. Because extreme heat (up to 3000° C) is generated during electrical burns which causes deep local tissue destruction.

Question 73. At what age electrical burns are common?
Answer. Most electrical burns occur in children younger than 4 years of age.

Question 74. Which areas of the oral cavity are often affected by electrical burns?
Answer. Electrical burns mostly affect the lips followed by the commissure; occasional involvement of tongue and gingiva may be seen.

Question 75. Describe the clinical appearance of electrical burn in the mouth.
Answer.

• Initially deep craters or charred yellow areas develop in the affected tissue, with no pain or bleeding
• Severe edema develops within few hours and the normal appearing surrounding tissue becomes ischemic and often produces a peculiar cold sensation.
• From fourth day the affected area becomes necrotic and slough out, leaving a large disfiuring defect; bleeding may start during this period due to exposure of large underlying vessels.

Question 76. Name the complications of electrical burn in orofacial tissues.
Answer.

• Contracture of mouth
• Late hemorrhage due to exposure of large vessels
• Microstomia, deformities of lip and face and facial palsy
• Anodontia and tooth malformation
• Loss of tooth vitality.

Question 77. Name the treatment outlines in case of electrical burns.
Answer.

• Tetanus immunization
• Antibiotic administration
• Use of tissue supported or tooth supported appliances to prevent development of microstomia
• Cosmetic reconstruction of face and mouth.

Question 78. Name the common causes of thermal burn in the mouth.
Answer. Thermal burns of the oral tissues occur mostly due to following causes:

• Contact with hot foods and beverages
• Accidental contact by hot dental instrument with oral soft tissues during dental procedures.

Question 78a. What is the fist response of the body to high environmental temperature?
Answer. Vasodilatation.

Question 79. Name the types of thermal burn of the mouth.
Answer. Thermal burns of the mouth are generally divided into three types—mild, moderate and severe.

Question 80. Which areas of the mouth are commonly affected by mild-thermal burn?
Answer. It often affects tip of the tongue and anterior part of the palate (since these anatomical structures come in contact with foods fist).

Question 81. Describe the clinical appearance of mild-thermal burn of the mouth.
Answer. In cases of mild thermal burn, the area shows slight erythema which resolves spontaneously in few hours time.

Question 82. How moderate thermal burns occur in the mouth?
Answer. This type of burn often occurs when hot sticky foods become adhered to the palate (especially hot cheese, etc) while eating.

Question 83. How the lesions clinically appear in moderate thermal burns?
Answer. The area becomes erythematous with sloughing of the epithelium; causing pain and burning sensation for many days.

Question 84. What are the causes of severe thermal burns in the mouth?
Answer. Severe burns occur mostly during dental procedures, when an overheated instrument or material comes in direct contact with the oral soft tissues. It particularly occurs during taking impression with an overheated hydrocolloid impression material.

Question 85. How the lesions clinically appear in case of severe thermal burn?
Answer. The gingival tissue is often damaged and it shows mucosal erythema and sloughing with intense pain.

Question 86. What are radiation injuries?
Answer. Radiation injuries occur due to the ionizing effects of electromagnetic waves or energized particles on living cells.

Question 87. Why the living cells or tissues get damaged due to exposure to radiation?
Answer. As radiations (which are tremendously powerful rays of energy) pass through any living cell, they cause damage to the cells or the tissue in the following manner:

• By direct effect: Radiation disintegrates or destroys the chemicals that constitute the cell and as a result the cell loses its ability to function or it may die.
• By indirect effect: Some toxic compounds (free radicals) are produced within the cells by ionizing radiation when the energy is absorbed; these free radicals combine to form toxic substances such as H2 O2, which damage the cells.

Question 87a. What is ionization in radiation injury?
Answer. It is the most destructive effect of radiation on the living cells; which often affects the DNA and causes damage to DNA leading to cellular death, mutations or genetic transformation, etc.

Question 88. From which sources radiation injuries can occur?
Answer. Radiation injuries may occur from the following sources:

• Sun (UV rays)
• X-ray machines
• Radioactive elements
• Atomic explosions by accident or during war.

Question 88a. What is radiotherapy?
Answer. Radiotherapy is the process of controlled elimination of diseased cells by deliberate use of radiation.

Question 89. Why adverse side effects occur in radiotherapy?
Answer. When radioactive rays are applied for therapeutic reason in the body to kill abnormal cells, it also causes damage to some normal cells in and around the fild of radiation.

Question 90. What are the types of therapeutic radiations?
Answer. Therapeutic radiations are of two types:

• Low energy radiation (less than 1000 KeV or ortho-voltage)
• High energy radiation (4 million to 25 million KeV or super voltage).

Question 91. For what purpose low energy radiations are used?
Answer. The low-energy waves are used for the treatment of superfiial skin or mucosal lesions; especially cancers, because the energy absorption in such cases mostly occur at the point of initial contact with the tissue.

Question 92. In which cases, high energy radiations are used?
Answer. When high-energy electromagnetic waves are used, the energy absorption mostly takes place in the deeper tissues and as a result the surface tissue like skin or epithelium, etc. is spared. High-energy electromagnetic waves are useful in the treatment of deep tissue neoplasms or metastatic lesions.

Question 93. What is rad (radiation absorbed dose)?
Answer. During radiotherapy treatment, the amount of cell damage depends upon the amount of energy the tissue absorbs. Generally this amount of energy is measured as rad.

Question 94. Name the factors determining the effectiveness of radiotherapy.
Answer.

• Stage of the cell cycle
• Mitotic index
• Nature of tissue.

Question 95. How the stage of cell cycle matters in the effectiveness of radiotherapy?
Answer. Immature or developing cells are more effectively destroyed during radiotherapy; because these cells e.g. cancer cells, bone marrow cells or cells of the fetus, etc arevery sensitive to radiation as compared to those of the more mature stages.

Question 96. Why mitotic index is important in the effectiveness of radiotherapy?
Answer. Lesions with high index of mitotic activity are more responsive to radiotherapy than the lesions with little or no mitotic activity.

Question 97. Name the cells which are extremely sensitive to radiations.
Answer.

• Cancer cells
• Thyroid gland
• Lymphoblasts
• Bone marrow cells
• Germ cells of ovaries and testes
• Lining epithelial cells of the intestine.

Question 98. Name the cells which are relatively non-sensitive (resistant) to radiations.
Answer.

• Nerve tissue
• Muscles tissue
• Brain tissue
• Endocrine glands
• Bone tissue
• Mature cartilage.

Question 99. Name the category of people who can be more susceptible to radiation injuries.
Answer.

• People working with radioactive materials
• People working at nuclear fision reactors
• People receiving therapeutic radiations
• People living in the city where a major nuclear disaster had struck e.g. explosion in the nuclear reactor or atom bomb explosion, etc.

Question 100. What is unit gray (Gy) used to measure?
Answer. Gray (Gy) is the SI unit of absorbed radiation dose of ionizing radiation and it measures the amount of radiation that different tissues can tolerate without being damaged.

Question 101. List different tissues and mention the amount of radiation they can tolerate without being damaged.
Answer.

• Fetus—2 Gy
• Bone marrow—2 Gy
• Ovaries—2 to 3 Gy
• Lens of the eye—5 Gy
• A child’s bone—20 Gy
• Adult’s bone—60 Gy
• A child’s muscle—20–30 Gy
• Adult’s muscle—100 Gy or more.

Question 102. Mention the possible consequences of radiation exposure in a living human cell.
Answer.

• Cell may be undamaged
• Cell may be damaged but remain functionally viable
• Cell may be damaged and function abnormally
• Cell may undergo complete necrosis.

Question 103. What is the earliest sign of radiation over-exposure in the body?
Answer. Skin erythema.

Question 103a. What are the effects of moderate doses radiation on skin?
Answer.

• Development of erythema
• Destruction of hair follicles, sweat and sebaceous glands
• Scarring, dryness and pigmentations
• Skin becomes less resistant to injury.

Question 104. Mention the effects of high-dose of radiation on skin.
Answer. Very high doses of radiation cause edema, swelling and desquamation of the skin with ulcerations.

Question 105. Describe the effects of radiation on oral mucosa.
Answer.

• Dryness, erythema and atrophy of oral mucosa
• Development of mucositis with necrosis, denudation and sloughing
• Ulceration occurs frequently causing pain and discomfort during meals
• Mucositis can cause dysphasia, cough, hoarseness of voice and loss of taste sensations
• Development of secondary infections following dental procedures
• Delayed wound healing and diffiulty in wearing prosthesis.

Question 106. Name the effects of radiation on salivary glands.
Answer.

• Development of xerostomia or dryness of mouth
• Saliva appears thick and its flw gets stagnant
• Sore mouth with diffiulty in food intake
• Pain and discomfort in mouth along with altered taste sensations
• Development of candidiasis and increased caries susceptibility.

Question 106a. At what dose of radiation salivary flw is completely stopped?
Answer. 6000 rads.

Question 107. What are the most common effects of radiation on temporomandibular joint?
Answer. Degenerative changes in the joint with subsequent firous ankylosis and trismus.

Question 108. Describe the common effects of radiation on vascular tissue.
Answer.

Increased thickening and distortion of walls of narrow vessels cause diminished blood supply. The ability of the vascular tissue to tolerate injury or trauma is greatly diminished; which results in increased susceptibility to infection and delayed wound healing Vascular insuffiiency due to radiation may result in some serious complication like bone necrosis.

Question 109. What are the effects of radiation on developing tooth?
Answer.

• High doses of radiation during the formative stage may cause complete degeneration of the tooth buds with no tooth formation in the future
• In other cases, there may be incomplete root formation and delayed eruption of teeth.

Question 110.Describe the various effects of radiation on erupted tooth.
Answer.

• There may be development of white, chalky or opaque areas on the tooth due to demineralization
• Softening with loss of translucency of enamel of teeth, this gets easily detached from tooth surface
• The erupted teeth often become non-vital and brittle with increased risk of fracture
• Development of radiation caries
• Serious destruction of the periodontal tissue may result in weakness in the teeth
• Xerostomia and osteoradionecrosis may contribute greatly to the premature loss of teeth.

Question 111. What is radiation caries?
Answer. A peculiar form of tooth destruction occurs in the cervical areas of several teeth following radiation, which resembles dental caries and hence known as radiation caries. It can cause severe destruction of tooth structure near the cement to enamel junction, which may lead to fracture of the affected teeth.

Question 112. Why bone tissue often gets non-vital following exposure to radiation?
Answer. It occurs mostly secondary to the damages that occur in the nutrient vessels supplying the particular bone.

Question 113. Name the common effects of radiation on bone tissue.
Answer.

• Retardation of growth in the developing bone due to damage to the metaphyseal growth cartilage
• Partial or complete loss of vitality of bone with increased risk of fracture
• Increased incidence of osteoporosis and delayed healing of bony wounds or fractures
• Frequent development of osteomyelitis and osteoradionecrosis.

Question 114. What is osteoradionecrosis of bone?
Answer. Osteoradionecrosis is an acute form of osteomyelitis with formation of sequestrum due to refractory infection and necrosis of the bone following radiotherapy.

Question 115. Why osteoradionecrosis of bone actually occurs?
Answer. The condition occurs secondary to radiation-induced damage of the intra-osseous blood vessels.

Question 115a. Mention the sequence of events taking place in the development of osteoradionecrosis.
Answer. Radiation-induced damage to bone followed by trauma and then secondary infection.

Question 115b. Why tooth extraction is contraindicated in the jaw where radiotherapy has been done previously?
Answer. Due to the risk of development of osteoradionecrosis.

Question 116. Describe the brief pathogenesis of osteoradionecrosis.
Answer. Radiotherapy causes intra-osseous vascular damages resulting in decreased blood supply to the bone tissue; as a result, the bone becomes partially non-vital. The inflmmatory defense capacity of such bone to the onslaught of secondary infections is often severely compromised. Trauma to such affected bone (e.g. during tooth extraction) often causes secondary infections eventually leading to the development of osteoradionecrosis.

Question 117. Which jaw bone has more risk of development of osteoradionecrosis?
Answer. Mandible is more often affected by osteoradionecrosis, since normally this bone has minimum vascularity.

Question 118. How secondary bacterial infections develop in the affected bone in case of osteoradionecrosis?
Answer. Bacterial infections enter the non-vital bone via the portals created by extractions of teeth, periodontal pockets, periapical lesions, traumatic injuries in the tissue due to surgery or wearing of prosthesis, etc.

Question 119. Describe the clinical features of osteoradionecrosis.
Answer.

• Ulceration, severe pain, swelling and formation of draining sinuses or fitulas on the alveolar ridge
• Exudation of pus from the area and presence of severe foul smell
• Malocclusion is common with development of trismus
• Sequestration of large fragments of necrotic bone from the affected area
• Possibilities of pathological fracture and permanent deformity in the bone.

Question 120. What is the radiological appearance of the affected bone in osteoradionecrosis?
Answer. Large areas of moth-eaten radiolucency are seen in the affected area of bone with presence of opaque sequestra.

Question 121. Describe the common treatment modalities in osteoradionecrosis.
Answer.

• Debridenent of necrotic tissues with removal of the sequestrum
• Administration of intravenous antibiotics and hyperbaric oxygen
• Maintenance of strict oral hygiene.

Question 122. Describe the different grades of osteoradionecrosis
Answer. In terms of severity and responsiveness to therapy, osteoradionecrosis are divided into three grades: Grade I, grade II and grade III.

Question 123. What is grade I osteoradionecrosis?
Answer. Grade I represents osteoradionecrosis of the jaw with exposure of the alveolar bone.

Question 124. What is grade II osteoradionecrosis?
Answer. When osteoradionecrosis not responding to hyperbaric oxygen therapy and requires sequestrectomy or saucerization it is called grade II type.

Question 125. What is grade III osteoradionecrosis?
Answer. It is osteoradionecrosis with full thickness involvement of bone and/or pathological fracture.

Question 126. What is the full form of LASER?
Answer. Light amplifiation by stimulated emission of radiation (LASER).

Question 127. Describe the common LASER-induced injuries of the orofacial tissues.
Answer.

• A chalky spot or a crater or a hole formation on the enamel surface
• Charring of the dentin with coagulation necrosis of the odontoblast cells
• Hemorrhagic necrosis of the pulp tissue with acute or chronic inflmmatory cell infitrations
• Nonspecifi ulceration on the oral epithelium with purulent inflmmation.

Question 128. What is congenital porphyria?
Answer. Congenital porphyria is a hereditary disease characterized by defective metabolism of hematoporphyrin, which results in the accumulation of excessive porphyrins in the blood or urine.

Question 129. What is the most common oral manifestation of congenital porphyria?
Answer. Discoloration of teeth is the commonest manifestation which occurs due to the deposition of circulatory porphyrins in the teeth at the time of mineralization. Clinically the teeth exhibit a pinkish-brown discoloration and bright-red florescence under ultraviolet light (erythrodontia).

Question 129a. Describe the other clinical features of congenital porphyria.
Answer.

• The skin appears light brown and is extremely sensitive to sunlight
• Blistering and erosions in the facial skin with severe scarring of the face
• Hemolytic anemia develops frequently with splenomegaly
• Bones are fragile with increased incidence of pathological fractures
• Vesiculo-bullous lesions often develop on the exposed skin surfaces, which heal with scarring
• Ocular damage can lead to development of blindness.

Question 130. What is biliary atresia?
Answer. Biliary atresia is an uncommon congenital disease of newborn infants characterized by narrowing or absence of the ductal elements of the biliary system of liver (the common bile duct between liver and small intestine is either blocked or it is absent). The condition results in elevated bilirubin levels in blood.

Bilirubin

Question 131. What is the common oral manifestation of biliary atresia?
Answer. Discoloration of teeth is the commonest oral manifestation of this disease, which mainly affects the deciduous teeth; the affected teeth appear dark or greenish in color; with roots of the teeth more intensely stained than the crowns.

Question 132. What is erythroblastosis fetalis?
Answer. Erythroblastosis fetalis is a hemolytic anemia of the newborn which develops during intrauterine life and results from incompatible factors in the blood of the mother and the fetus.

Question 133. Describe the brief pathogenesis of erythroblastosis fetalis.
Answer. During pregnancy, an Rh-negative mother normally develops antibodies against the erythrocytes of an Rh-positive fetus. Severe hemolysis with subsequent production of biliverdin and bilirubin (blood pigments) occurs if the maternal antibodies cross the placental barrier and attack and destroy the fetal erythrocytes.

Question 134. What are the oral manifestations of erythroblastosis fetalis?
Answer.

• Green or bluish-green or yellowish-gray discoloration of deciduous teeth due to excessive deposition of bilirubin
• There may be occasional development of enamel hypoplasia of teeth.

Question 135. What are the sources of arsenic poisoning?
Answer. Mostly drinking water, but also can be from food and air.

Question 135a. What are the clinical signs of arsenic poisoning?
Answer. Weakness, headache, burning eyes, abdominal pain,hemoptysis, dyspnea and paresthesia.

Question 135b. What is typical dermal and mucosal pigmentation seen in arsenic poisoning known as?
Answer. Rain drop pigmentation.

Question 135c. Which body parts can be useful as samples in detection of chronic arsenic poisoning?
Answer. Nail clippings, hair and bone, etc.

Question 135d. What are the oral manifestations of arsenic poisoning?
Answer.

• Gingivitis and stomatitis with painful mucosal ulcerations,
• Hyperpigmentations and hyperkeratosis of oral mucosa
• Excessive salivation, vomiting, diarrhea and neurological disturbances.

Bilirubin

Question 136. Describe the oral manifestations of lead poisoning.
Answer.

• Excessive salivations and swelling of the salivary glands
• Metallic taste in the oral cavity and development of a dark lead line along the gingival margin.

Question 136a. What is the term used to designate lead poisoning?
Answer. Plumbism.

Question 136b. What is the common clinical sign in arsenic, lead and mercury poisoning?
Answer. Excessive salivation.

Question 137. What is a lead-line?
Answer. In cases of lead poisoning, a dark stippled blue line forms along the gingival margin, which occurs due to perivascular depositions of lead-sulfie in the submucosa and basement membrane zone.

Question 137a. What is the other name of lead line?
Answer. Burtonian line.

Question 137b. What is the gingival manifestation of mercury poisoning?
Answer. It produces a black line on the gingiva that follows the contour of marginal gingiva.

Question 138. Describe the oral manifestations of bismuth poisoning.
Answer.

• Burning sensations in the oral mucosa with metallic taste in mouth
• A blue-black bismuth line seen on the marginal gingiva
• Blue-black pigmentations are also seen on the lips, buccal mucosa, vestibule and undersurface of the tongue, etc.

Question 139. Name the major clinical and oral manifestations in mercury poisoning.
Answer.

• CNS disturbances in the form of tremors, headache, depression and insomnia, etc.
• Depressed immunity as this metal is immunotoxic
• Extreme exhaustion, fever and weight loss, etc.
• Excessive salivation with salivary gland swelling, loosening of teeth
• Stomatitis, glossitis and development of a dark black line on the free gingival margin.

Question 139a. What is the other name of mercury poisoning?
Answer. Acrodynia or pink disease.

Question 140. What are the oral manifestations of silver poisoning?
Answer.

• An ashen–gray discoloration of the skin and oral mucosa
• Microscopy reveals a fie black, granular, deposition of silver salts in the sub mucosa.

Question 140a. What is the other name of silver poisoning?
Answer. Argyria.

Question 141. What are the oral manifestations of cytotoxic drug therapy?
Answer.

• Anodontia, hypoplastic crowns of teeth with short roots and enamel defects
• Gingival hyperplasia, dry mouth and mucosal pigmentation.

Question 142. Name the common systemic reactions in cytotoxic drug therapy.
Answer.

• Bone marrow depression
• Depressed cell mediated immunity
• Lichenoid reactions
• Stevens-Johnson’s syndrome
• Fixed drug rash
• Toxic epidermal necrolysis.

Question 143. What is tetracycline staining of teeth?
Answer. Tetracycline drug has got selective affiity for the calcium ions of the tooth surfaces and bone. It causes staining of teeth possibly by forming a complex substance with the calcium ions of the hydroxyapatite crystals of enamel of tooth or bone (calcium chelation), which becomes deposited on the tooth or bone surfaces during mineralization of their organic matrix.

Question 144. When tetracycline drug should not be administered to avoid staining of teeth?
Answer. To avoid tetracycline staining the drug should not be administered during the second and third trimester of pregnancy and to the infants (up to the age of seven years)

Question 144a. By which process, tetracycline causes intrinsic staining of teeth?
Answer. Calcium chelation.

Question 145. How teeth appear in tetracycline staining?
Answer.

• The affected teeth exhibit a yellowish or brownish-gray discoloration (internal staining)
• Microscopic section of the affected tooth often produces bright yellow florescence under ultraviolet light.

Question 146. Mention the various staining produced by different types of tetracyclines.
Answer.

• Chlortetracycline: Brownish-gray discoloration of teeth
• Oxytetracycline: Yellowish discoloration of teeth.

Question 147. What is angioneurotic edema?
Answer. Angioneurotic edema is a kind of allergic reaction which frequently produces rapidly developing, smooth, diffuse, edematous swelling in the face, lips, eyes, tongue and extremities.

Question 148. Name the risk factors which might trigger angioneurotic edema.
Answer. The disease occurs due to allergic reactions because of the following:

• Insect bites and contact with pollen and scales of shed animal skin
• Drug allergy and exposure to water or sunlight
• Eating foods, e.g. berries, fih, meat, eggs and milk, etc.

Question 149. What may be the most fatal consequence in angioneurotic edema?
Answer. The edema develops very rapidly and it also subsides rapidly after lasting for about 24 to 36 hours. However on rare occasions, angioneurotic edema may cause edema glottis that result in suffocation or even death.

Question 150. What is aspirin burn?
Answer. When acetylsalicylic acid is put directly inside mouth to relieve pain (particularly toothache),it slowly gets dissolved in the saliva and liberates a strong acidic solution, which often causes necrosis of the mucosa. This type of oral injury is called aspirin burn.

Question 151. Describe the clinical appearance of aspirin burn.
Answer.

• Aspirin burn produces a localized, white, friable area on the mucosa with pain
• In severe cases, removal of the superfiial white layer of the epithelium reveals a raw, erosive surface with bleeding tendency
• Patients often complain of burning pain in the mouth.

Question 152. List different chemicals, which might cause chemical burns in the mouth and mention their respective uses.
Answer.

• Phenol: Used as disinfectant
• Silver nitrate: Used as cauterizing agent
• Trichloro acetic acid (TCA): Used as chemical cauterizing and gingival retracting agent.
• H2 O2: Used as root canal medicaments
• Bleaching agents: Used for tooth whitening.

Question 152a. Name the effects of overuse of chlorhexidene mouthwashes?
Answer.

• Staining of teeth
• Transient loss or alteration of taste sensations.

Question 152b. What should be the ideal concentration of chlorhexidene in a mouthwash?
Answer. It should be 0.2 percent.

Question 153. What is the drug of choice in acute allergy with bronchospasm and hypotension?
Answer. Epinephrine.

Question 154. Which nerve is damaged due to prolonged administration of streptomycin?
Answer. Auditory nerve.

Question 155. What is stomatitis medicamentosa?
Answer. Allergic reactions to oral mucosa following systemic administration of a drug.

Questionuestion 156. What is stomatitis venenata?
Answer. An inflmmation of the oral mucosa as the result of contact allergy.