Dental Biochemistry

Front 1

1. What is hyperglycemia?

Back 1

High blood glucose seen in individuals w/ untreated or poorly controlled diabetes mellitus

Front 2

2. How is poorly controlled diabetes related to dental caries?

Back 2

They elevated salivary glucose (on outside of bacterial cell membrane)

Glucose transverse bacterial cell membrane

Anaerobic glycolysis to form lactate

Lacate (inside) to lactic acid (outside)

Lactic acid increases incidence of dental caries

**short term consequence of diabetes

Front 3

3. What are some long term complications of diabetes?

Back 3

1. Hyperglycemia (elevated blood glucose) can cause glycoslation of proteins

2. Glycosylated proteins can slowly crosslink and undergo other nonenzymatic reactions

3. Form advance glycation end products
-damaged proteins of microvasculature nerve tissue

Front 4

4. What does glycosylation do to proteins?

Which proteins are especially vulnerable?

Back 4

Impairs structure and function

Endothelial cells and basement membrane proteins of the microvasculature and proteins of nervous tissue

Front 5

5. What do these damaged proteins result in damage to?

Back 5

Kidneys

Retina

Nerves

Heart disease infections

Front 6

6. What is glycosylated hemoglobin called?

Does it cause clinical problems?

Back 6

HbA1c

No b/c its affinity for oxygen and other properties are not significantly altered

**In presence of glucose, hemoglobin can add glucose to end

Front 7

7. What does the percent of hemoglobin present in blood as HbA1c provide?

What is the life span of RBC?

What does HbA1c percentage provide then in terms of diabetes?

Back 7

Index of integrated glucose concentration over life span of RBC

100 to 120 days

Indicates how well patient is controlling diabetes (blood glucose levels) over past 3 months

Front 8

8. What is a normal HbA1c value?

How are the results judged for a diabetic?

Back 8

4% to 6% HbA1c

-7% or less: excellent blood sugar control

-7.1% to 8.0%: good control
-8.1% to 9.0% : fair control
-9.1% or higher: poor control

Front 9

9. What does higher HbA1c put a person at risk for developing?

Back 9

Diabetic eye, kidney, or nervous system disease

Front 10

10. What dental problems do diabetics w/ poor long term control of blood glucose commonly experience?

Six...

Back 10

1. Tooth decay
-salivary bacteria thrive so have high acidic environment
2. Periodontal disease
3. Salivary Gland Dysfunction
4. Fungal Infections (oral candidiasis)
5. Infection and delayed wound healing
6. Taste impairment

Front 11

11. Why can diabetes cause increased risk of periodontal disease?

Three reasons...

Back 11

1. Altered tissue metabolism

2. Increased salivary glucose (rise in "food" for bacteria)

3. Increase salivary Ca leading to an increase in tartar formation

Front 12

12. What is an example of a salivary gland dysfunction?

Back 12

Xerostoma (dry mouth)
-damage to micro vessels in gland

Bacterial growth thrives w/o saliva so lead to more tooth decay and accelerates periodontal disease

Front 13

13. Why does oral candidiasis (fungal infection) occur in people w/ diabetes?

Back 13

Diminished salivary flow and increase in salivary glucose create attractive environment for fungal infections

Produce white (or red) patches in mouth that may be sore or become ulcers

Front 14

14. How is taste impaired in diabetics?

Back 14

May have diminished ability to taste sweets

May influence food choices in favor of sweet tasting foods (highly refined carbohydrate content)

Front 15

15. What is an early sign of diabetes that dentists can look for?

Back 15

Unexplained tooth loss

Front 16

16. What is hypoglycemia?

In diabetics it's most common due to what?
(four things)

What else can it sometimes be caused by in non-diabetics?

Back 16

Low blood glucose

1. Too much insulin
2. Drugs that enhance insulin action
3. Too little food
4. Too much exercise

Insulinoma (insulin producing tumor)
Glycogen storage disease

Front 17

17. When does glucose availability become the rate-limiting step for glycolysis?

Back 17

When blood glucose levels are much below 80 mg/dL

Glucose availability to brain and nervous tissue is decreased

Front 18

18. Should a patient follow their normal insulin and food intake schedule before dental work?

Why or why not?

Back 18

Yes

Dental treatment may result in higher stress levels so body's requirements for insulin may increase

Front 19

19. Should a patient delay eating or skip a meal following dental work (may be due to numbness or appointment timing)?

Why or why not?

Back 19

No

Want to avoid a hypoglycemic (low blood sugar) attack

Front 20

20. What may hypoglycemia cause?

Back 20

1. Symptoms related to low levels of sugar supplying the brain
-headache, dizziness, blurred vision, confusion, weakness, loss of consciousness, coma

2. Symptoms related to epinephrine and norepinephrine
-sweating, tremors, anxiety, hunger (stress response)

Front 21

21. During a protein meal, how are blood glucose level?

How are glucagon levels during a protein meal?

How are insulin levels during a protein meal?

Back 21

Maintained

Rise stimulated by release of AA by protein digestion

Small rise also stimulated by AA

Front 22

22. What does the rise in glucagon stimulate after a protein meal?

Back 22

Increase in glycogenolysis and gluconeogensis

**This is why glucose remains constant

Front 23

23. What does increased insulin stimulate after protein meal?

Back 23

Stimulates AA uptake into tissue

Increases protein synthesis

Minor insulin increase is not enough to inhibit glycogenolysis or gluceneogensis

Front 24

24. How are glucagon levels after a mixed meal of carbs and proteins?

How are insulin levels?

Back 24

Stays relatively constant

Similar pattern of high carbohydrate meal

Glucose suppresses glucagon and protein increases glucagon

Front 25

25. In diabetics what happens to gluconeogensis and glycogenolysis?

What may this be due to?

What is this a major cause of?

Back 25

Not turned off by insulin in fed state or by high glucose in fasting state

Insulin resistance and to increased availability of glycerol and AA

Postprandial and fasting hyperglycemia

Front 26

26. How is the glucagon levels relative to ineffective insulin?

What does this result in?

Back 26

High (despite hyperglycemia)

Elevated gluconeogensis (turned on all the time)

Increase glycogenolysis b/c have lots of glycogen

Front 27

27. In diabetes what other metabolic processes increase?

What happens in muscle cells often in diabetics?

Back 27

Lipolysis and proteolysis

Glucose is not taken in so think deficient and increase gluconeogensis even more

Front 28

28. In the fed state what is the source of glucose?

In the fasting state (8 to 1.5 days) what is the source of glucose?

Back 28

Ingested glucose

Glycogenolysis (easier to break down glycogen than make glucose)

1.5 days though glycogenolysis stops b/c liver glycogen is depleted (still have muscle glycogen if not exercising)

Front 29

29. At 16 hours after eating what significant thing happens?

What is the source of glucose in the starved state?

Back 29

Glycogenolysis and gluconeogensis cross (equivalent)

From here gluconeogensis becomes more dominant source of glucose

Gluconeogensis

Front 30

30. In the liver in the fed state which hormone and enzyme is high?

Back 30

Insulin (high blood glucose)

High F-2,6-P
(shuts down gluconeogensis in fed state)

Front 31

31. What is the cori cycle?

Back 31

Glucose to the brain and RBC

In RBC glucose is converted lactate

Lactate is used to regenerate glucose in the liver

Front 32

32. During the fasting state how are the hormone levels insulin and glucagon?

How is glucose?

What happens to various metabolic pathways?

Back 32

Decrease insulin
Increase glucagon

Decrease glucose

Turn on glycogen break down
Have gluconeogensis
FA β-oxidation and KB synthesis

Front 33

33. When does the basal state occur?

Back 33

After an overnight (12 hour) fast

Front 34

34. In the fasting state what hormone and enzyme is low?

How is glucose?

Back 34

Glucagon
Liver F-2,6-P

Blood glucose is low

Front 35

35. How is blood glucose levels through weeks of fasting?

Why does this occur?

What else is used as a fuel?

Back 35

Constant

Conserve blood glucose by increasing availability of alternative fuels
-conserve glucose and use stored fuels most efficiently

FA and ketone bodies

Front 36

36. How is body protein conserved during fasting?

In the starved state what is the metabolic pathway that is completely relied upon and why?

What does muscle rely completely on in the starved state and why?

Back 36

After 3-5 days of fasting, brain utilizes ketone bodies

Gluconeogensis b/c glycogen is depleted

Solely on FA (stop using KB so brain can use them)

Front 37

37. If a person has a defect in glucose 6-phosphatase how would this affect glucose levels 2 to 4 hour after mean and after an overnight fast?

Back 37

2 hours after meal - no effect

4 hours after meal - no effect

Overnight fast - no gluconeogenesis
-blood glucose levels drop

Front 38

38. If a person has a genetic defect in an enzyme involved in liver glycogen degradation what would happen to their blood glucose levels after an overnight fast?

Back 38

Can't break down glycogen (no glycogenolysis)

Hypoglycemic

Front 39

39. A person has a genetic defect in an enzyme in muscle glycogen degradation. What effect would this have on the person's blood glucose when at rest and when exercising?

Back 39

At rest
-no effect really b/c purpose of glycogen in muscle is not to support blood glucose

Exercising
-stimulate glucose transport into muscle and get glucose from blood b/c can't get it from muscle glycogen (mild hypoglycemia)