physical and chemical injuries commonly encountered during dental procedures

3. CONTENTS
• INTRODUCTION
• INJURY
• INJURIES OF TEETH ASSOCIATED WITH TOOTH PREPARATION
• EFFECT OF HEAT
• EFFECT OF RESTORATIVE MATERIALS
• PHYSICAL INJURIES OF TEETH
• PHYSICAL INJURIES OF BONE

4. • EFFECT OF ORTHODONTIC TOOTH MOVEMENT
• PHYSICAL INJURIES OF SOFT TISSUES
• RADIATION INJURIES
• CHEMICAL INJURIES OF ORAL CAVITY
• OCCUPATIONAL INJURIES OF THE ORAL CAVITY
• OCCLUSAL TRAUMA
• CONCLUSION
• REFERENCES

5. INTRODUCTION
• Oral lesions associated with trauma are a relatively common finding in dental
practice. A diverse array of oral mucosal disorders caused by acute and chronic
trauma exists.
• They manifest in the oral mucosa as acute or chronic ulcers, white or red lesions,
mucositis, and reactive hyperplasia or even as bone exposures with
sequestration.
• Such lesions may also impair oral functions to a significant extent and also pose
some difficulties in arriving at a diagnosis especially the chronic lesions.

6. • Similarly chemical injury could result from undue or careless handling of
chemicals and dental instruments during dental treatment procedures.
• A wide array of chemicals and drugs come into contact with oral mucosa and
some of them may cause direct mucosal trauma due to their caustic nature.
• Some people tend to apply certain chemicals as a remedy for their oral
problems such as application of aspirin to ease toothache.
• Health care practitioners are also responsible in applying certain chemicals in
the mouth for treatment or investigative procedures.
Chemical burns

7. INJURY
• It is defined as harm or hurt; usually applied to damage inflicted on the body by
an external force, called as trauma or wound

8. Injuries of the Teeth Associated with Restorative Procedures
Effect of Tooth Preparation:
• The effect of preparation of teeth on dentin and pulp alone is difficult to asses
except in sound teeth since the carious lesion itself produces demonstrable
changes in both these structures.
• Rotary instruments with stainless steel burs, tungsten carbide and diamond burs
of different sizes and shapes are routinely employed to prepare cavities and
crowns.

9. Reactions to Rotary Instrument
• Hence preparation of tooth without adequate cooling or excessive drying of the
dentin after cavity preparation results in excessive heat and evaporation of
tubular contents.
• This leads to displacement of odontoblast nuclei into the dentinal tubules and a
marked disorganization in the organelles of the odontoblasts and in the adjacent
cells, which might include intracellular disorganization, rupture of the nuclear
membrane and lysis of cellular elements.

10. • Effect of air abrasive techniques:
• Aluminum oxide under high pressure is use. It does not allow the stereognostic
ability of the controller. Working time is the most important to determine the
depth of preparation.
• Effect of Ultrasonic Technique:
• It has been advocated as it involves less heat, noise and vibration in contrast to
rotary instruments.

11. • Studies have shown that there is no remarkable differences in the reaction of
dental pulp to steel burs, diamond burs or ultrasonics.
• Lasers
• Carbon and Nd:YAG are most commonly used.
• On tooth it produces a glass like fusion of the enamel and definitive charred
crater on dentin.
• On pulp it shows severe pathologic changes including hemorrhagic changes
with acute & chronic inflammatory cell infiltrations.

12. Effect of Heat
• Thermal changes are influenced by
1. The size, shape & composition of bur or stone
2. The speed of bur or stone
3. The amount & direction of pressure applied.
4. The amount of moisture in the field of operation.
5. The length of time that the bur or stone is in contact with the tooth
6. The type of tissue being cut, enamel or dentin

13. SMEAR LAYER
 The cut surface of enamel and dentin, when examined after preparation with
hand instruments or burs reveals the presence of covering layer of cutting
debris from mineralized tissues referred as the “smear layer” which is less than
2μ.

14. Effect of Restorative Materials
• Remaining Dentin Thickness(RDT):
–It is the most important deciding factor before placing the restorative materials.
–2μ or more is sufficient for proper insulation by the dentin itself.
–If its less than 2μ additional agents such as cements or bases are required before
placing the restoration.
Zinc Oxide & Eugenol:
• Eugenol of the cement fixes cells, depresses the cell respiration and reduces the
neural transmission in vitro.
• It is considered as the least injurious of all filling materials to the dental pulp.
Zinc Phosphate cement:
• Majority of investigators have reported significant deleterious effects on the pulp
when the material is placed, the actual injurious agent is supposedly being the
phosphoric acid.

15. Silver Amalgam:
• It is used as filling material which is generally innocuous material, particularly in
shallow cavities.
• However Manley found that there is decrease in odontoblasts number with mild
inflammation of pulp.
• New studies have found that the pulp response is due to the leakage around the
restoration rather than the material by itself. There is slight inflammation of
gingiva when contacted due to the corrosive products & plaque.

16. Glass Ionomer:
• Its is considered as biocompatible and is widely used as filling, lining and luting
agent.
• It has the advantage of chemically bonding to the mineralized tissue and release
of fluorides.
• Pulpal pain may be present for a short period after the filling material due to the
increased dentin permeability after acid etching.

17. • Self Polymerizing Acrylic Resin:
• Extensively used as restorative materials, particularly in anterior teeth.
• Results indicated that these resins provoked odontoblastic damage and pulpal
inflammation which is more severe in deeper restorations.
• Pulpal reaction is mainly due to the shrinkage causing leakage.
Conventional Composite Resins:
• These showed the same irritational characteristics of unfilled resins.
• Hence pulpal protection is required in such cases to prevent damage and calcium
hydroxide base is a preferred.

18. Microfilled Composite Resins:
• It is comparable to those of conventional composite resins hence pulp protection
is required under deep cavities.
Acid Etching:
• Most commonly employed chemical is phosphoric acid.
• This considerably demineralize the dentin exposing collagen. It forms an
interwoven mesh of fibers in which resin is infiltrated forming a “hybrid layer.”

19. Effect of Cement Bases, Cavity Liners, Varnishes and
Primers
• These are generally used for one or more of the following purposes:
1. To serve as bacteriostatic agent.
2. To provide thermal insulation, particularly under metallic restorations.
3. To provide electrical insulation under metallic restorations.
4. To prevent the discoloration of tooth structure adjacent to certain type of
restorative materials.
5. To prevent the deleterious constituents of restorative materials into dentin
and pulp; and
6. To improve the marginal seal of certain restorative materials by preventing
microleakage and the ingress of saliva and debris along the tooth-
restoration interface.

20. PHYSICAL INJURIES OF TEETH
• Bruxism
–It is the habitual grinding or clenching of the teeth , either during sleep
or as an unconscious habit during waking hours.
–Includes both clenching habit & also to the repeated tapping of the
teeth.
– Bruxism is one of the most common sleep disorder.
–According to Nalder and Meklas it described as
i. Local
ii. Systemic
iii. Psychological and
iv. occupational

21. Why?

22. • Local Factors : associated with some form of mild occlusal disturbances which
produces mild discomfort and chronic, even though unrecognized, tension.
• Systemic Factors: it includes gastro-intestinal disturbances, subclinical nutritional
deficiencies etc.

23. • Psychological Factors: it is the most common cause for bruxism. High levels of
anxiety, stress and emotional tension may be expressed through a number of
nervous habits, one of which may be bruxism.

24. • Occupational: certain occupations lead to this habit. Athletes engaged in
physical activities and in occupations in which the work is unusually
precise, such as that of watchmaker it is seen.

25. • Clinical Features:
–According to Glaros and Rao
a. Effects on dentition
b. Effects on periodontium
c. Effects on masticatory muscles
d. Effects on temporomandibular joint
e. Head pain and
f. Psychological and behavioral effects.
• Treatment & Prognosis:
–Underlying cause must be cured first.
–Removable splints which are worn at night to immobilize the jaws or guide the
movement so that periodontal damage may be minimal.
–Botulinum toxin (Botax) is used now a days injected in masseter muscle without
effecting chewing or facial expressions.
–If left untreated, severe periodontal and/or temporomandibular disturbances may
result.

26. • Fractures of Teeth:
–Commonest injury which may arise in variety of situations, the most
frequent of which is sudden severe trauma such as fall, blow, an
automobile accident or any of a large number of incidents in which
children especially are frequently involved.
–It mostly involves boys and anterior maxillary teeth.

27. –Most followed classification is
Ellis & Davis.
• Class 1- simple #(Fracture) of
crown, involving little or no
dentin.
• Class 2- extensive # of the
crown, involving dentin but
not dental pulp.
• Class 3- involvement of pulp
in addition to class 2

28. • Class 4- the traumatized
tooth becomes non vital with
or without loss of crown
structure
• Class 5- teeth lost as a result
of trauma

29. • Class 6- # of root with or without
loss of crown structure.
• Class 7- displacement of a tooth
without # of crown or root.
• Class 8- # of crown en masse and its
replacement
• Class 9- traumatic injuries to
deciduous tooth.
• The treatment is based on whether
there is exposure of pulp or not and
the time elapsed after the trauma.

30. • Root Fractures:
–These are uncommon in young children as
their socket is not much developed with
resilience.
–Mostly seen in between ages 10-20.
–Depending on site of fracture there may be
loss of crown or mobility of crown
structure.
–In some cases there is formation of dentin
barrier and cementum resulting in healing
of the fracture.

31. • Abrasion:
–Wearing away of tooth substance due to mechanical means is known as
abrasion.
–Commonly seen in habits like holding pins, opening bottles with teeth etc., in
some occupations such as tailoring, carpentering etc.

32. • Injuries to the supporting structures of tooth:
–Concussion:
• it is produced by injury which is not strong enough to cause serious, visible
damage to the tooth and the periodontal structures.
• Characterized by increased sensitivity of tooth to percussion in any direction.
• Treatment include selective
grinding of teeth to remove
occlusal contacts.

33. –Subluxation:
• Refers to abnormal loosening of tooth without displacement due to sudden
trauma.
• Tooth is mobile on palpation and sensitive to percussion and occlusal forces
with gingival bleeding in the crevice.
• In time it becomes non-vital due to severance of apical blood supply.

34. –Avulsion:
• Dislocation of the tooth from its socket due to traumatic injury. It can
be partial or total.
• Partial avulsion includes intrusion, extrusion, or facial, lingual, or
palatal, or lateral displacement.
• It is usually associated with fracture of socket.

35. • Partial can be treated by repositioning and splinting of teeth.
Complete avulsion can be treated by re-implantation.
• It success is dependent on time elapsed from injury to the placement
and medium in which it is carried.

36. • Tooth Ankylosis:
–Fusion between bone and tooth, termed ankyloses is an un common
phenomenon in deciduous dentition and even more rare in permanent
dentition.
–Ankylosis ensues when partial resorption of tooth has occurred and
replaced with bone or cementum uniting the tooth with bone during repair.
–Usually becomes apparent during tooth
removal, which considerable difficulty will
be encountered, sometimes necessitating
surgical removal.
–No specific treatment unless removed for
some other reason, should serve well
indefinitely.

37. PHYSICAL INJURIES OF THE BONE
• Fractures of Jaws:
–Most common physical injury involving bone.
–It occurs during accidents such motor vehicles, fall form heights, sports, fights
etc.
–It may be of simple, greenstick, compound, comminuted or impacted.

38. –Fractures of Maxilla:
• These are more serious than mandible
fractures.
• Classified by Le Fort includes
• Le Fort 1 or horizontal #, also known as
floating # is characterized by separation
of body of the maxilla from the base of
the skull, below the level of zygomatic
process.

39. • Le Fort 2 or pyramidal # is
characterized by vertical #
through the facial aspects of
the maxilla and extend
upward to the nasal and
ethmoid bones and usually
extends through the
maxillary sinus.

40. • Le Fort 3 or transverse # is a
high level of # that extends
across the orbits through the
base of the nose and ethmoid
region to the zygomatic arch.
Bony orbit is #ed and the lateral
rim is separated at the
zygomaticofrontal suture.
Zygomatic arch is #ed.

41. • Over view of all three fracture lines.

42. –Fractures of Mandible:
• Most common in road traffic
accidents and physical
violence.
• It most commonly involves the
angle of mandible, which is
followed by condyle, molar
region, mental region and
symphysis.
• Displacement depends on the
direction of the line of #,
muscle pull and the direction
of force.

43. • Features are similar to other #s such as pain, abnormal mobility,
lacerations, bleeding etc.
• Treatment includes reduction and immobilization like other #s.
• Complications are malunion, nonunion and fibrous union.

44. –Traumatic Cyst:
• It is pseudo cyst & an
uncommon lesion in bone.
• Many theories have been
proposed but the trauma-
hemorrhage theory is
widely accepted.
• According to the
hemorrhagic theory, the
clot breaks down and
leaves an empty cavity
within the bone.

45. • When cavity is opened surgically
either a small amount of
serosanguinous fluid, shreds of
necrotic blood clot, fragments of
fibrous connective tissue or
nothing.
• Radiographically it reveals a
rather smoothly outlined
radiolucent area of variable size,
some times with a thin sclerotic
border, depending on the
duration of the lesion.

46. • Focal Osteoporotic Bone-Marrow Defect of the Jaw:
–Occurs in angle of mandible, tuberosity etc.
–Unusual demand for blood production causes osteoporosis of marrow and even
thinning the cortex.
–Other theories include unusual healing of the extraction socket(mostly
associated with it).

47. • Surgical Ciliated Cyst of Maxilla:
–Develops after surgical entry into maxillary sinus(Cadwell-Luc
operation) or due to obstruction of ostium.
–Majority of patients belong to middle age group with non-specific, poorly
localized pain, tenderness or discomfort of maxilla.
–Filling defect is seen radiographically.
–Treated by enucleation

48. • Effects of Orthodontic Tooth
Movement:
–General principle in
orthodontic tooth
movement involves
resorption on pressure side
and deposition of bone on
tension side resulting in
tooth movement within the
bone.

49. • Tipping movement:
–The exact movements which a
tooth will undergo and the exact
position it will assume after the
application of orthodontic force
and the position of fulcrum
around which the force acts.
–New bone is formed on the outer
surface of labial cortex if pressure
is applied labially to maintain the
cortical thickness and prevent
perforation of the cortex during
tooth movement.

50. Other movements which follow the same pattern are torquing &
rotation

51. –Extrusive tooth movement:
• It is similar to normal eruption.
• Movement consist in deposition or
apposition of new bone spicules at the
alveolar crest and at the fundus of the
alveolus arranged in a direction
parallel to the direction of force
–Intrusive or Depressive movement:
• Tissue changes result in opposite of
extrusive tooth movement and new
bone formation is minimal.

52. • Tissue reaction during retention period:
• During this period there is gradual reformation of the normal dense pattern of
the alveolar bone by apposition of bone around the bony spicules until they
meet, fuse and gradually remodel.
• The final remodeling and the attainment of absolute bone-tooth equilibrium
following orthodontic tooth movements involve an extremely slow process
and is responsible for orthodontic failure due to relapse during retention
period.
• Studies have found that the
deciduous tooth movement is
followed by the permanent
tooth germ.

53. PHYSICAL INJURIES OF SOFT TISSUES
• Linea Alba:
• It is a white line seen on the buccal mucosa extending from the
commissures posteriorly at the level of the occlusal plane.
• Caused by physical irritation and pressure by the posterior teeth. Seen
bilaterally. Common in bruxism patient or clenching habit.

54. –Toothbrush Trauma:
• This injury occurs to the gingiva and is produced by the tooth brush.
• Appears as white, reddish or ulcerative lesions or linear superficial
erosions,
• involving marginal & attached gingiva of maxillary canine &
premolar region.

55. • Traumatic Ulcer:
–It is caused by some form of trauma.
–This may be due to biting of mucosa, denture irritation, tooth brush
injury, exposure of OMM to sharp tooth or carious lesion etc.

56. • Factitial Injuries:
–These are self-induced injuries.
These may be habitual, accidental
or may have psychogenic
background.
• Lip biting or Cheek biting:
• These injuries are habitual or
psychogenic.
• It involves holding, biting &
tearing of the epithelium of lip,
buccal mucosa or tongue, chewing
of cheek or stripping of the
epithelium using fingers or
creating negative pressure by
sucking the lips & cheeks.

57. –Intra & Perioral Piercing:
• Body piercing is the act of
puncturing or cutting a part of the
human body, creating an opening
in which jewelry may be worn.
• Eye brow, ear, ala of nose, lip,
tongue etc., are used.
• Complications include edema,
hemorrhage and infection,
mucosal or gingival trauma,
chipped or fractured teeth,
increase salivary flow, calculus
build up, gingival recession etc.

58. • Denture injuries:
–Traumatic ulcer:
• Commonly results after insertion of a new denture.
• May be result of over extension of the flanges, sequestration of spicules
of bone under the denture or a roughened or high spot on inner surface
of the denture.
• These are small, painful,
irregularly shaped lesions
usually covered by delicate
gray necrotic membrane
and surrounded by
inflammatory halo.

59. –Generalized Inflammation:
• It occurs in patients who may or may not have a new set of dentures.
• It may not be due to allergy. In some cases it is due to Candidal infections.
• The mucosa beneath the denture becomes extremely red, swollen, smooth or
granular and painful. Multiple pinpoint foci of hyperemia involving maxilla
may occur.
• The redness of the mucosa is
rather sharply outlined &
restricted to the tissue
actually in contact with
the denture.

60. –Inflammatory (Fibrous) Hyperplasia:
• One of the most common tissue reactions to a chronically ill-fitting
denture is the occurrence of hyperplasia of tissue along the denture
borders.
• Characterized by the development of elongated rolls of tissue in the
mucolabial or mucobuccal fold area into which the denture flange
continuously fits.

61. • Inflammatory Papillary Hyperplasia:
–Unusual condition involving mucosa of palate mostly associated with ill
fitting dentures. Often associated with chronic hyperplastic candidiasis
–The lesion presents itself as numerous, closely arranged, red, edematous
papillary projections, often involving nearly all of the hard palate and
imparting to it a
warty appearance.

62. • Denture Base Intolerance or Allergy:
–Plasticizers of the soft liners are cytotoxic and effect many cellular
metabolic reactions in vitro.
–It is very rare.
–This reaction may
be due to sensitivity
to the monomer,
both regular &
self curing types.

63. • Mucous Retention Cyst:
–Generally conceded to be of
traumatic origin.
–Usually results due to the obstruction
of ducts of minor or accessory
salivary glands.
–There may be chronic partial
obstruction by small pieces of dental
calculus or other products.
–These have been classified as:
1. An extravasation mucocele or
2. A retention mucocele (true
retention cyst)

64. • Ranula:
–Mucocele but larger, which specifically occurs in the floor of the mouth in
association with the ducts of the submaxillary or sublingual gland.
–It slowly enlarges painlessly on one side of the floor of the mouth.
–The mucosa may have a translucent bluish colour. It may sometimes
herniates through mylohyoid muscle causing plunging ranula.

65. • Retention Cyst of Maxillary Sinus:
–It is uncommon and because of the possibility of confusing it with a
variety of other lesions occurring in the same location
–Causative factors include sinusitis, allergy and sinus infection but these
are without firm support.

66. • Sialolithiasis:
–A stone in the salivary ducts or
glands is called sialolithiasis.
–They are formed by deposition of
calcium salts around a central nidus.
–It can be complete or partial & may
show recurrence. Many patients
involved with major salivary gland
reported with moderately severe
pain , particularly just before, during
and after meals owing to psychic
stimulation of salivary glands.

67. –Maxillary Antrolithiasis:
• Defined as a complete or partial calcific encrustation of an antral
foreign body, either endogenous or exogenous, which serve as nidus.
• Generally asymptomatic but may present with symptoms like pain,
nasal obstruction &/or foul discharge & epistaxis.

68. Condition Diagnosis Common sites of
occurrence
Management
Linea Alba
clinical Buccal mucosa Explanation and
reassurance, no specific
treatment required
Mucosal Biting Clinical Buccal mucosa, lip and
lateral border of the
tongue
Explanation and
reassurance, advice on
habitual biting
Riga-Fede disease Clinical Tip or ventral surface of
the tongue
Extraction of neonatal
teeth
Eosinophilic ulcer Biopsy Gingiva Spontaneous healing
Ulcers caused by self-mutilation or
self-injury
Clinical Gingiva Psychological
assessment and
counselling
Ulcers due to oral trauma in
patients with congenital
insensitivity to pain
Clinical Lips and tongue Symptomatic
treatment, prevent
trauma from sharp
edges of teeth
Electrical and Thermal Burns Clinical Lips and tongue Surgical excision and
reconstruction
Summary of oral mucosal traumatic lesions and their management
Condition Diagnosis Common sites of
occurrence
Management
Trauma associated with sexual
practices
clinical Soft palate, lips Symptomatic
management
Denture associated hyper keratosis Clinical Alveolar ridge Elimination of irritation
from the denture
Denture associated ulcers Clinical Buccal and lingual sulci Trim the denture to
eliminate trauma
Inflammatory papillary
hyperplasia
Clinical Palate Anti-fungal treatment,
surgical excision
Epulis fissuratum clinical Buccal sulcus Surgical excision and
vestibuloplasty

69. –Radiation Injuries:
• The general term radiation is referred to two different forms of energy
–Electro magnetic radiation and
–Particulate radiation.
• General effects of radiation
–The cellular injury has been postulated to be due to a number of
possible factors
• Toxic effect of protein breakdown products.
• Inactivation of enzyme systems.
• Coagulation or flocculation of protoplasmic colloids.
• Denaturation of nucleoproteins

70. • Effects of Radiation on Oral & Para oral tissues:
–Depend upon great number of factors such as the source, total amount,
period of time of radiation administered, type of filtration & total area of
tissue irradiated.
–There is bilateral parotitis, partial xerostomia and oral mucostitis
following total body radiation.

71. • Effects on Skin:
–Erythema is the earliest visible reaction and begins within a
few days after irradiation.
–Altered sebaceous gland activity resulting in decrease in
secretions and cause dryness & scaling of the skin.
–Superficial blood vessels become telangiectatic or occluded.

72. • Effects on Oral Mucosa:
–Same as those as in skin with erythema and mucostitis follows.
• Effects on Salivary Glands:
–Xerostomia is one of the most commonest and earliest complaints of
all.
–The loss of secretion may be a permanent condition or there may be
gradual return of salivation after several months.

73. • Effects on Teeth:
–Radiation caries is most common problem after radiation.
–Mostly due to altered changes in the salivary glands.
–Developing tooth are particularly very sensitive to X-ray radiation.
–There may be complete cessation of odontogenisis or stunting of
growth of teeth depending upon the time of radiation

74. • Effects on Bone:
–Bone itself is relatively resistant to X-ray radiation, although osteoblasts
are sensitive.
• There is lack of proper response to healing of radiation injuries in bone like
other type of injuries leading to complications like osteoradionecrosis and
longer the period between radiation and extraction less chances are there to
develop osteoradionecrosis.
• Osteoradionecrosis:
–It is an acute form of osteomyelitis caused by damage to the intraosseous
blood vessels & is characterized by a chronic, painful infection and
necrosis accompanied by late sequestrum and some permanent
deformity.
–There is lack of osteoblasts in turn lack the capacity to produce new bone.

75. • The walls of regional blood vessels are thickened by fibrous connective
tissue resulting in devitalization of bone due to lack of reparative
capacity.
• The devitalized bone is not demarcated and occurs throughout the
entire irradiated area of bone.
• Factors leading to osteoradionecrosis is
–Irradiation of an area of previous surgery before adequate healing
had taken place.
–Irradiation of lesions in close proximity to bone.
–A high dose of irradiation with or without proper fractionation
–Use of a combination of external radiation and intra oral implants
–Poor oral hygiene and continued use of irritants.

76. –Poor patient co-operation in managing irradiated tissues or fulfilling
home care programs
–Surgery in the irradiated area
–Indiscriminate use of prosthetic appliances following radiation therapy
–Failure to prevent trauma to irradiated bony areas and
–Presence of numerous physical & nutritional problems prior to therapy.

77. CHEMICAL INJURIES OF ORAL CAVITY
• One of the most commonest reaction to drugs or chemicals is the allergic
phenomenon, the two main types of that are of dental interest being
–Drug allergy or stomatitis medicamentosa and
–Contact stomatitis or stomatitis venenata.

78. • Non-allergic Reaction to Drugs and
Chemicals used Locally:
–Aspirin:
• Used by many people as local
abtundent for the relief of
toothache.
• Within a few minutes after
placement of the aspirin powder
there is burning sensation of
mucosa & the surface becomes
blanched or whitened in
appearance. Healing of painful
aspirin burn take a week or
more.

79. • Endodontic Materials:
–Sodium Hypochlorite
• It produces damage when injected beyond apex.
• On contact with vital tissue it causes hemolysis & ulceration, inhibits
neutrophil migration and damages endothelial and fibroblast cells.
• Life threatening airway obstruction has been reported secondary to
hypochlorite
extrusion.

80. –Hydrogen Peroxide:
• Similar to effects of hypochlorite.
• In addition causes irritation to the cementum & periodontal ligament
leading to cervical root resorption.

81. • Non Allergic Reactions to Drugs & Chemicals
Used Systemically:
–This reaction is often a part of a generalized
epidermal reaction, but other times it occurs
as a specific phenomenon apparently due to
anatomic peculiarity.
–Arsenic:
• Occupational hazard, widely used in
metal industry.
• Inflammation of OMM & severe gingivitis.
• Local contact produces ulceration &
systemic poisoning causes excess
salivation

82. • Bisphosphonate:
–It is a potent anti resorptive agent used in many diseases involving
resorption.
–Osteonecrosis incidence is associated with bisphosphonate.
– Osteonecrosis of jaw
probably results from
the inability of
hypodynamic &
hypovascular bone
to meet an increased
demand for repair &
remodeling.

83. • Bismuth:
–Pigmentation of oral mucosa, particularly gingiva & buccal mucosa
is common oral feature in bismuth therapy especially when
receiving preparations containing metal
–The pigmentation appears as a bismuth line, a thin blue-black line in
the marginal gingiva is sometimes confined to the gingival papilla.
The pigmented granules consists of sulphides.

84. • Dilantin Sodium:
–Extensively used in the control of epileptic seizures.
–Gingival hyperplasia is the side effect which can avoided with good oral
hygiene practices.
–First noted as painless increase in size of the gingiva, starting with
enlargement of one or two interdental papilla.
–The surface of gingiva shows an increased stippling & finally a
cauliflower, warty or pebbled surface.

85. • Lead:
–Lead poisoning(plumbism) occurs chiefly as an occupational hazard
today but occasionally as acute or chronic nature.
–Manifested as serious GIT disturbances which include nausea, vomiting,
colic and constipation.
–Peripheral neuritis may produce characteristic wrist-drop or foot-drop.

86. • Mercury:
–It may be of acute or chronic and acute form are serious.
–Chronic is characterize by gastric disturbances, diarrhea, excitability,
insomnia, headache and mental depression.
–Increased salivation and metallic taste in mouth. Salivary glands may be
swollen and tongue is also sometimes enlarged and painful. Hyperemia
and swelling of the gingiva are occasionally seen.

87. • Acrodynia:
–It is mostly due to mercury poisoning in acute cases or as an idiosyncrasy
to the metal. Source is mainly teething powder or mercury containing
ointments, lotions or disinfectants.
–In young infants below the age of two years.
–The skin particularly of the
hands, feet, nose, ears & cheeks
become red or pink and has a
cold, clammy feeling.

88. •Silver:
–Chronic exposure to silver compounds may occur as occupational hazard
or as a result of therapeutic use of silver compounds.
–Appearance of a slate-blue silver line along the gingival margins arising
due to deposition of metallic silver & silver sulphide pigments is one of
the earliest signs.
–Amalgam tattoo of OMM is a
relatively common finding in
dental practice, generally
occurring in four ways.

89. • Tetracycline:
–Discoloration of either deciduous or permanent teeth may occur as a
result of tetracycline deposition during prophylactic or therapeutic
regimes by pregnant woman or postpartum infant.
–The severity of the staining by tetracycline is determined by the stage of
tooth development at the time of drug administration.
–Teeth affected appear to
have a yellowish or
brownish-gray
discoloration which is
most pronounced at the
time of eruption of teeth.

90. OCCUPATIONAL INJURIES OF THE ORAL CAVITY
• They occur as a result of work or occupational activity.

92. OCCLUSAL TRAUMA
• Occlusal changes can cause in the alveolar bone and periodontal
connective tissue both in the presence and in the absence of
periodontitis.
• Occlusion & local irritants are two factors in the etiology & pathogenesis
of periodontal disease.

93. • Acute trauma occurs when biting hard food substance or a high filling
resulting in pain, sensitivity to percussion and slight mobility.
• When excessive forces occur in different directions results in widening of
periodontal ligament.
• Chronic occlusal trauma is relatively more common than acute forms.
• In this the PDL gradually becomes denser and the periodontal space
widens.

95. CONCLUSION
• As prosthodontist we should be able to diagnose the different
conditions which lead to the trauma and treat the underlying cause.
• All precaution should be taken to prevent injuries to the patient during
the treatment.
• It is best advised to use proper preventive barriers such as rubber dams
to prevent chemical exposure during treatment and also careful
handling of the materials during use.
• Additional care should be taken while using rotary instruments in the
oral cavity. Instrument should be started and stopped in the cavity only
to prevent injury to the adjacent soft tissues.
• Sound knowledge and prompt remedies should be known to the dentist
if any mishaps occur in the clinic.

96. REFERENCES
• Shafer’s text book of Oral Pathology-6th Edition.
• Iatrogenic injury of oral mucosa due to Chemicals: A Case
report of formocresol injury and review - Girish M S, IOSR
Journal of Dental and Medical Sciences Volume 14, Issue 4.
• Traumatic Oral Mucosal Lesions: A Mini Review and
Clinical Update- Ariyawardana Anura, OHDM - Vol. 13 -
No. 2 - June, 2014.