Management of Medically Compromised Children Contents : Introduction Definition Classification Heart disease Blood Dyscrasias Endocrine Disorders Respiratory Disease Psycho-behavioural Disease Renal Disease AIDS References

1. Dr. Arun Sharma
Professor and Head
Dept. of Pedodontics and Preventive Dentistry
Rama Dental College-Hospital & Research Centre, Kanpur

2. Index
Introduction
Definition
Classification
Heart disease
Blood Dyscrasias
Endocrine Disorders
Respiratory Disease
Psycho-behavioural Disease
Renal Disease
AIDS
References

3. Introduction
 A medically compromised condition is where the child
suffers from certain systemic conditions which puts him at
a risk when regular dental treatment is required.
 Due to this, a pedodontist has to take certain precautions
so as to enable him to go through the treatment without
any complications.
 Children with systemic conditions and special needs such
as cancer, bone marrow and other organ disorders, diabetes
or asthma are accepted in the clinic and comprehensive
dental care is provided with close cooperation with the
child’s physician.

4. Introduction
 The comprehensive care required by these children is
time consuming and many patients as well as their
families are uncooperative.
 The dentist, who extends his responsibility beyond the
treatment of the 'chief complaint' however, will find
great rewards in helping the disabled patient and his
family adjust to and deal effectively with long-term
disability.

5. Definition
 A Medically compromised child is the term used to
describe children who are suffering from any type of
medical ailment which can be of short or long
duration. The extent of the disability depends on the
severity of the disease.
 WHO defines a handicapped individual as "One who,
over an appreciable time, is prevented by physical or
mental condition from full participation in the normal
activities of his age group, including those of a social,
recreational, educational and vocational nature".

6. Classification
Nowak has divided handicapping conditions into 9
categories:
1. Physical
Cerebral palsy
2. Mental retardation
3. Congenital defects
Congenital cardiac disease
Cleft lip and palate
Down's syndrome

7. 4. Metabolic and systemic disorders
Renal diseases and liver disease
Diabetes mellitus
Hypo/hyperpituitarism
Hypo/hyperthyroidism
Hypo/hyperparathyroidism
Respiratory disorders
Immunological disorders
5. Convulsive disorders
6. Childhood Autism
7. Blindness and deafness
8. Hematological disorders
9. Neoplasias
Classification

8. Classification
 Handicapping conditions have also been divided into:
Intrinsic- "one from which the person cannot be
separated". eg medical and physical disabilities.
Extrinsic- "one from which the person can be removed". eg
social deprivation.
 Handicapping conditions can also be:
Mental handicap
Physical handicap
Medical handicap

9. Heart Disease
There are two types of heart conditions, i.e. congenital
and acquired.
 Congenital
 Acyanotic
 Cyanotic
 Acquired
 Infective endocarditis
 Rheumatic fever

10. Congenital Heart Defect (CHD)
 Congenital heart defect is usually due to an
aberrant embryonic development of a normal
structure or the failure of the structure to progress
beyond an early stage of embryonic development.
 Etiology
 Usually multifactorial and there is an apparent
interaction between genetic and environmental factors
 Maternal rubella, maternal diabetes and drugs during
pregnancy (alcohol, phenytoin)
 Children with inborn errors of metabolism and
connective tissue disorders
 Syndromes like Down's Syndrome, Williams Syndrome

11. Acyanotic CHD
In this condition there is minimum or no cyanosis.
 Two different categories
 First consisting of defects that causes left-to-right shunting of
blood within the heart (atrial septal defect and ventricular
septal defect).
 The second category consists of defects that cause obstruction
(aortic stenosis, coarctation of the aorta).
 Clinical manifestation:-
 Congestive heart failure
 Pulmonary congestion
 Heart murmur
 Laboured breathing
 Cardiomegaly

12. Cyanotic CHD
 In this condition cyanosis is seen on minimum
exertion due to right to left shunting of blood within
the heart (Teratology of Fallot, transposition of great
vessels, pulmonary stenosis, tricuspid atresia).
 Clinical Manifestations
 Cyanosis
 Hypoxic spells
 Poor physical development
 Heart murmurs
 Clubbing of fingers and toes.

13. Acquired Heart Disease
RHEUMATIC FEVER
 It can occur at any age, but is rare in infancy.
 Most commonly it appears between 6 and 15 years of age.
 The condition can be fatal in acute stage or it can lead to a
chronic rheumatic heart disease as a result of scarring of
the valves
Clinical Manifestations
 Diagnosis is made by the presence of
 One required criteria, two major criteria, and zero minor
criteria OR
 One required criteria, one major criteria, and two minor
criteria.

14. Acquired Heart Disease
REQUIRED CRITERIA
 Evidence of streptococcal infection(eg: increased titer of
anti-streptococcal antibodies; positive throat culture for
group A streptococcus; recent scarlet fever).
MAJOR DIAGNOSTIC CRITERIA:-
•Carditis
•Polyarthritis
•Erythema marginatum
•Subcutaneous nodules

15. Acquired Heart Disease
MINOR DIAGNOSTIC CRITERIA:-
•Fever .
•Arthralgia.
•Previous rheumatic fever or rheumatic heart disease.
•Acute phase reactions (ESR/ CRP/ Leukocytosis).
•Prolonged PR interval.

16. Acquired Heart Disease
INFECTIVE BACTERIAL ENDOCARDITIS
It is characterized by microbial colonization of the heart
valves or the endocardium.
Two forms are present:-
•Acute
•Subacute
In the acute form, a fulminant disease occur as a result of
infection with highly virulent micro-organisms like
Staphylococcus and Pneumococcus.
The subacute variety develops in individuals who already
have an existing congenital cardiac disease or rheumatic
valvular lesions, caused by viridians streptococci.

17. Acquired Heart Disease
Clinical Symptoms:-
•Low irregular fever with
sweating.
•Malaise
•Anorexia
•Weight loss
•Arthralgia
•Inflammation of
endocardium

18. Dental Treatment Considerations
for Cardiac Patients
•Careful dental evaluation is needed and required dental
treatment should be completed before any surgery.
•Preventive dental programmers to be implemented.
•To decrease the incidence of post-operative
endocarditis from oral sources.
•Consultation with cardiologist.
•Antibiotic prophylaxis is needed.
•Dental treatment should be completed at least 3 to 4
weeks before the planned surgery to allow healing and
return of the normal micro flora.

19. Dental Problems and Treatment
•Prior to treatment complete medical history should be
elicited and consultation with the child’s cardiologist.
•Antibiotic prophylaxis may be recommended in infective
endocarditis patients in the dental procedures which induce
gingival bleeding like scaling, minor surgeries, incision and
drainage, intraligamentary injections etc.
•Dental procedures that do not require prophylaxis include
those which may not induce gingival bleeding such as simple
orthodontic appliances, filling above the gum line, injections
of local anesthetic except intraligamentary and palatal.
•Pulp therapy is not recommended due to the high risk of
chronic infection. Instead, extraction of the offending tooth
and its replacement with a space maintainer is advocated.

20. •In the permanent dentition, endodontic therapy may be
undertaken after a careful evaluation and case selection. ( a
tooth with poor prognosis is better removed)
•Oral sedation and nitrous oxide inhalational sedation may
be beneficial in reducing anxiety and minimizing risk.
•Orthodontic treatment should be done under antibiotic
prophylaxis, especially band placement and removal.
•In the patients who are on anticoagulant therapy
hematological monitoring and cessation of anticoagulant
therapy are important before any dental surgery is
undertaken.
•Children suffering from severe , debilitating heart disease
requiring extensive dental work-up should be treated in a
Dental Problems and Treatment

21. Blood Dyscrasias
ANEMIA
•Anemia occurs due to deficiency of RBCs either by rapid loss,
slow production or defective functioning of RBCs.
•The condition causes decrease in oxygen carrying capacity of
blood.
CLINICAL FEATURES OF ANEMIA
•Pallor of skin and mucosa
•Fatigue weakness
•Breathlessness on exertion
•Palpitations, cardiac murmurs
•Dizziness

22. ORAL MANIFESTATIONS
•Pallor of mucosa
•Decreased healing response
•Atrophic glossitis
•Angular cheilitis
•Beefy red tongue seen in
megaloblastic anemia
•Mucosal conditions like apthous
ulcers may be seen.
Blood Dyscrasias

23. Blood Dyscrasias
IRON DEFICIENCY ANEMIA
•Type of anemia: Microcytic, hypochromic anemia
•Chronic blood loss along with food deficient in iron, faulty
iron absorption and increased requirement of iron during
infancy, childhood etc.
•Children are more susceptible to iron deficiency anemia.
•Found in conjugation with a prolonged bottle feeding habit
where the transition to balanced solid diet has been
incomplete and where cow's milk continues to be main
dietary component
•It is one of the most common types of anemia in INDIA.
•Plummer-Vinson syndrome associated with iron deficiency
anemia exhibits dysphagia due to oesophageal constriction.

24. Blood Dyscrasias
MEGALOBLASTIC ANEMIA
 The deficiency of either vitamin B12, folic acid or the
intrinsic factor
 Can lead to very slow maturation of erythroblasts in the
bone marrow.
 As a result they grow too large with odd shapes and are
called ‘megaloblasts’.
 Pernicious anemia is a type of megaloblastic anemia in
which deficiency of vitamin B12 is due to absence of
intrinsic factor.

25. Blood Dyscrasias
APLASTIC ANEMIA
•It is caused due to bone marrow disorders, affecting red
blood cells, white blood cells and platelets.
It is divided into two types
•Primary-idiopathic, or autoimmune
•Secondary – exposure to drugs, chemical substances or
radiation

26. Blood Dyscrasias
HEREDITARY ANEMIAS
THALASSEMIA
•Thalassemia is also known as Cooley’s anemia,
Mediterranean anemia and erythroblastic anemia.
•Manifests in three clinical forms:-
•Thalassemia major
•Intermediate Thalassemia
•Thalassemia minor

27. SICKLE CELL ANEMIA
 In this an abnormal haemoglobin ‘s’ is produced due to
defective beta chain synthesis of haemoglobin.
 Sickle cell trait is a benign condition.
 Children with sickle cell anemia frequently exhibit a vicious
cycle called a ‘sickle cell crisis’ in which low oxygen
tension in the tissues causes sickling of RBCs, which causes
obstruction of blood flow through capillaries,.
 Once the process starts it progresses rapidly and leads to a
serious decrease in RBCs, intravascular sickling, producing
thrombosis and infarction within a few hours and may be
fatal.
Blood Dyscrasias

28. Blood Dyscrasias
HEREDITARY SPHEROCYTOSIS
•The RBCs are small and spherical in shape rather than
biconcave.
•They rupture easily when passing through the spleen.
ERYTHROBLASTOSIS FOETALIS
•When an Rh negative mother conceives a Rh positive
child, the maternal immune system produces antibodies
against the child’s RBCs.
•The child shows a severe haemolytic reaction and exhibits
marked anemia after birth.

29. Dental Management of Blood
Dyscrasias
•Consult with chid’s physician or haematologist .
•Emergency dental procedures should not be performed
without physicians consult.
•Determine the haemoglobin level of blood prior to any dental
procedure.
•Patients with sickle cell anemia and thalassemia receive
repeated blood transfusions.
•So these children are at greater risk of acquiring infections like
HIV and Hepatitis.
•Patient with cardiac problem secondary to anemia are at high
risk and should be treated in a hospital under medical
supervision.

30. Platelet Disorders
THROMBOCYTOPENIA
•It is characterized by decrease in the number of platelets
in blood.
•The skin of children shows many small, purplish areas ,
hence called as ‘thrombocytopenic purpura’.
•Bleeding does not occur until the platelet count falls below
50,000/mm cube (normal 1,50,000-3,50,000/mm cube)
DENTAL MANAGEMENT
•Consultation with child’s physician or hematologist.

31. Platelet Disorders
•Blood transfusion prior to any invasive procedure may be
required in case of severe deficiency.
•All possible measures to control bleeding should be
available.

32. Other Bleeding Disorders
HEMOPHILIA
•It is a bleeding disorder caused due to deficiency of Factor
VIII in blood.
•It is transmitted as an X- linked recessive trait.
•Seen mostly in males, while females remain carriers.
Types of Hemophilia
•Hemophilia A(Classical hemophillia)-deficiency of factor
VIII.
•Hemophilia B (Christmas disease)-factor IX deficiency.
•Hemophilia C/Puedohemophilia (Von Willebrand’s
disease)-impaired platelet function.

33. Other Bleeding Disorders
ORAL AND DENTAL PROBLEMS:-
•Spontaneous Gingival bleeding.
•Physiologic process like tooth eruption and exfoliation may
be accompanied by hemorrhage.
DENTAL MANAGEMENT:-
•Consultation with child’s physician or hematologist.
•Minor injuries like lacerations due to the slippage of
instruments, placement of matrix band, scaling etc. must be
avoided.

34. Other Bleeding Disorders
•Minor bleeding should be controlled with pressure packs
and hemostatic agents.
•Use of local anesthetics, especially nerve blocks are
contraindicated.
•Restorative procedures and pulp therapy may be carried
out.
•Electrosurgical procedures are not recommended.

35. Leukaemia
 It is a malignant neoplasm of hematopoietic cells that
proliferate initially in the bone marrow before
disseminating to the peripheral blood, spleen, lymph
nodes, and ultimately other tissues.
 These immature appearing, undifferentiated blast cells
replace normal cells in the bone marrow leading to
anaemia, thrombocytopenia and abnormal white cell
count.

36. Leukaemia
Classification
It is classified according to the morphology of the
predominant abnormal white cells in the bone marrow.
They are further classified according to the progression of the
clinical course as acute or chronic.
 Acute Lymphocytic Leukemia.
 Acute Myelocytic Leukemia.
 Acute Non Lymphocytic leukemia
 Acute Myelocytic Leukemia
 Acute monocytic or Myelomonocytic Leukemia
 Erythroleukemia
 Megakaryocytic Leukemia

37. Leukaemia
 Chronic Myelocytic Leukemia
 Juvenile
 Adult
 Chronic Lymphocytic Leukemia
ETIOLOGY
•Cause in most patients is unknown, although both
genetic and environmental factors are important.
•Increased frequency in children with syndrome’s like
Down’s syndrome.

38. Leukaemia
Environmental factors:-
•Ionizing radiation
•Chemicals like benzene
•Aromatic hydrocarbons
•Immunodeficiency and prolonged immunosuppression
may lead to lymphoid malignancies.

39. Leukaemia
CLINICAL MANIFESTATIONS
•Anemia and thrombocytopenia with resultant pallor.
•Fever
•Tachycardia
•Adenopathy
•Gingival bleeding
•Increased irritability
•Lethargy
•Vague bone pain
•Hepatosplenomegaly

40. Leukaemia
ORAL MANIFESTATIONS
•Seen in 29% of children.
•Regional lymphadenopathy
•Gingival abnormalities including hypertrophy and bleeding
•Gingiva is boggy, edematous, deep red and bleeds easily.
•Ulceration and pallor of oral mucosa.
•Rapid loosening of teeth due to necrosis of the periodontal
ligament.
•Manifestations in the jaw include loss of trabeculations,
destruction of the crypts of developing teeth, loss of lamina
dura, widening of the periodontal ligament space and
displacement of the teeth.
•Oral changes can be attributed to anemia, granulocytopenia
and thrombocytopenia.

42. Dental Treatment in Leukaemia
•As infection is the primary cause of death in 80% of
children with leukemia followed by bleeding, the primary
aim of the dental treatment should be to prevent, control
and remove oral infection, inflammation and hemorrhage.
•Consult the child’s physician prior to any treatment and
take a complete medical history
•Elective dental procedures should be postponed if the
child is not in remission unless there is a nidus of infection
that could be a potential source of systemic infection.
•Avoid prescribing drugs like aspirin that can alter platelet
function.

43. Dental Treatment in Leukaemia
•As candidiasis is common, topical or systemic antifungals may be
used.
•Pain from ulcerative lesions can be relieved by application of
topical obtundents.
•For deep lesions that bleed spontaneously, apply topical bovine
thrombin.
•Pulp therapy on primary teeth is contraindicated and endodontic
treatment on permanent teeth is not recommended.
•If platelets are less than 20,000/cubic mm dental treatment
should be delayed.
•Avoid mouth brushing and substitute with moist gauze wipes
containing chlorhexidine if platelet count is low.
•Management of xerostomia by the use of sugarless sweets, sorbitol
based gums, artificial saliva and topical fluoride may be done.

44. Diabetes Mellitus:
•It is the most common endocrine disease of childhood.
•It is often associated with an inadequate supply of insulin to meet
physiologic needs of the body at the cellular level.
The primary disease manifests in two forms:-
•Type I or insulin dependent diabetes mellitus(IIDDM)
•Type II or non- insulin dependent diabetes mellitus(NIDDM):-

45. GENERAL SIGNS AND SYMPTOMS:-
Early features:-
•Polyuria
•Polydypsia
•Pruritus
•Weakness
•Recent weight loss
•Constipation
•Mental confusion
•Acetone breathe
Late features:-
•Vomiting, nausea
•Abdominal pain
•Renal dysfunction
•Hyperventilation
•Dehydration
•Hypovolaemia

46. •Shock
•Coma
Oral manifestations:-
•Reduced salivary flow
•Candidiasis
•Altered taste
•Progressive periodontitis.
•Dental caries.

48. Dental Management:-
•Comprehensive medical history along with screening test for
diabetes are essential.
•Dental appointments should be short, stress free and as
atraumatic as possible.
•Early morning appointments are preferred and the patient should
eat a normal breakfast before the appointment to prevent
hypoglycemia.
•Conscious sedation is preferred than deep sedation.
•Use of pulp capping and deciduous pulpotomy procedure is
questionable in child with uncontrolled diabetes but vital pulp
therapy may be preferred.

49. •In a non – vital tooth with evidence of infection extraction is only
the treatment of choice.
•Prophylactic antibiotics may be recommended in use of surgical
procedures.
MEDICAL TREATMENT:-
•In case of type I, insulin is administered.
•Insulin is administered at meal times and blood glucose levels are
measured at least twice a day.
•A well- balanced nutritious diet based on meal and snack structure
with appropriate carbohydrates particularly high in fiber is essential.
•Oral hypoglycemic drugs are used to stimulate insulin production

50. •Strict patient compliance is essential for effective treatment in
both types.
MANAGEMENT OF DIABETIC EMERGENCIES:-
Hypoglycemic attack and insulin shock:-
It develops due to stress, insulin overdose and poor dietary control
or glucose levels at or below 40mg/dl.
Signs and symptoms:-
•Mood changes and irritability.
•Disorientation, blurred vision.
•Sweaty skin.
•Loss of consciousness
•Lethargy, slurred speech.
•Strong, bounding pulse.
•Nausea and stomach ache.

51. •Hunger, shaking, tingling around the mouth.
•Increased gastric motility.
•Hypothermia.
MANAGEMENT OF INSULIN SHOCK:-
•Administer oral carbohydrates such as candy or orange juice and
soft drinks.
•If no recovery is seen within 2 – 5 minutes and the patient is
unconscious administer –
•Intravenous dextrose(50 ml in 5% concentration).
•Intramuscular glucagon (1 mg ) followed by i.m. epinephrine(0.5
mg of 1:1000 concentration).

52. •If the patient does not respond within 5 minutes emergency
procedures should be initiated.
DIABETIC CRISIS OR
HYPERGLYCEMIA:-
•It develops when blood glucose level rises over 11.1 mmol /L.
SIGNS AND SYMPTOMS:-
•Weak pulse
•Rapid and deep breathing.
•Dry skin.
•Acetone breath.
•Increased frequency of micturition.
•Thirst.

53. •Severe hypotension.
•Abdominal pain and vomiting.
•Loss of consciousness.
•A diabetic coma occurs at glucose levels between 300 – 600 mg/dl
when ketones are present in the urine and blood pH is below 7.35.
MANAGEMENT OF HYPERGLYCEMIC REACTION:-
•Maintain open airway in hospital unit.
•Administer 100% oxygen along with i.v fluids to prevent vascular
collapse.
•Perform finger stick blood glucose test.
•Administer insulin under controlled conditions.
•Patient recovery is slower than for insulin shock.

54. RESPIRATORY DISEASES:-
CYSTIC FIBROSIS:-
•It is a monogenetic disorder (autosomal recessive).
•It presents as a multi system disease involving exocrine glands.
Characterized by:-
•Chronic obstruction.
•Airway infection.
•Maldigestion caused by pancreatic insufficiency and other
abnormalities of the digestive tract.
•Incidence is 1 in 2000 live births.

55. ORAL MANIFESTATIONS:-
•Discolouration of teeth due to tetracycline therapy, enamel
hypoplasia.
•Changes in salivary viscosity and composition.
•High incidence of mouth breathing, open bite associated with
chronic nasal and sinus obstruction.
•Oral ulcerations.
•Dental development and eruption are delayed.

56. DENTAL PROBLEMS AND TREATMENT:-
•Complete medical history should be taken.
•Patient can be treated in an upright position to enable the
clearance of secretions.
•Anterior tooth discolouration can be treated with composite
veneering or jacket crowns.
•General anesthesia should be considered with antibiotic coverage.
•Dietary advice with sugar free liquid antibiotic preparation.

57. ASTHMA:-
•It is a disease of airways that is characterized by an increased
responsiveness of the tracheobronchia to a multiplicity of stimuli.
Clinical features:-
•Most common in 30 years of age.
•2:1 M:F preponderance.
•10% children are affected.
•Characterized by paroxysms of dyspnoea, cough and wheezing.

58. DENTAL PROBLEMS AND TREATMENT:-
•Complete medical history should be taken.
•Seat the patient in upright position.
•Treat child soon after a dose of medication is given and if child is
using an inhaler it should be brought along the dental appointment
in case of an attack.
•Sedation, G.A, L.A can be given.
•Use of aspirin, NSAID’S, and penicillin is contraindicated.

59. PSYCHOBEHAVIOUR DISORDER:-
AUTISM:-
•It is a severely incapacitating disturbance of mental and
emotional development that causes problems in learning,
communication, and relating to others.
•Incidence :- occurs in approximately 5 in 10,000 births.
•4 times more common in boys.

61. Clinical Manifestations:-
These children have:-
•Poor muscle tone.
•Poor co- ordination.
•Drooling.
•Hyperactive knee jerk.
•Strabismus.
•Epilepsy.
•Poor tongue co – ordination.
•Aggressive or destructive behaviour.
•They can be listed as extreme loneliness, language disturbance,
mutism, parrot like, repetitious speech, difficulty with concept of
yes.

62. MANAGEMENT:-
•Phenytoin therapy may lead to gingival sequel.
•Use tell – show – do and positive re – inforcement.
•Pre – operative sedation with muscle relaxant should be given.
•Psychotherapy and family counseling for success of oral hygiene
programme should be carried out.
•G.A in case of extensive treatment.

63. RENAL DISEASES:-
CHRONIC RENAL FAILURE:-
•It can be defined as a progressive and irreversible decline in the
total number of functioning nephrons with a concomitant decline
in glomerulo filtration rate.
CLINICAL MANIFESTATION:-
•Fatigue, headache, anorexia, nausea, polyuria, polydypsia,
muscle cramps, paresthesia, facial puffiness dryness, itchiness of
skin, pale brownish complexion, growth retardation, muscle
weakness, uremic breathe.

64. Oral manifestation:-
•Soft tissue changes are more common.
•Hard tissue changes occur in advanced cases.
DENTAL MANAGEMENT:-
•Precaution against transmission of serum hepatitis during dental
management.
•Antibiotic prophylaxis before dental treatment.
•Increased need for oral prophylaxis due to increase in calculus
formation.
•Steroid supplementation may be given prior to G.A for major
dental procedures.

65. AIDS:-
•It can be defined as presence of antibodies to HIV and
opportunistic infections.
•It is caused by HIV a human RNA retrovirus.
Mode of transmission:-
•Parenteral transmission.
•Perinatal transmission.
•Sexual transmission.
•Body fluids transmission.
Typical pediatric findings(Rubensteins, 1986):-
•Pulmonary lymphoid hyperplasia.
•Salivary gland enlargement.
•Pyogenic bacterial infection.
•Chronic recurrent diarrheoa.

66. •Hepato – splenomegaly.
ORAL AND PERIORAL FINDINGS OF AIDS IN CHILDREN:-
•Fungal infection like candidiasis
•Angular cheilitis.
•Bacterial infections.
•Viral infections like:-
i.Herpes zoster.
ii.Herpes simplex.
•Hairy leukoplakia.
•Apthous stomatitis.
•Gingival and periodontal lesions like:-
i. ANUG.
ii. NUP.
•Oral ulcerations.

67. •Kaposi Sarcoma

68. Dental Management:-
•Proper medical history of the patient
•Barrier techniques like :-
•Eye protection in terms of eye glasses.
•Mouth mask.
•Disposable needles.
•Gloves.
•Change of clothes.
•Proper sterilization.