Lecture 8- Clinical Correlates Flashcards
(139 cards)
1
Q
What synthesizes bone?
A
Osteoblasts
2
Q
What resorbs (breaks down) bone?
A
Osteoclasts
3
Q
What makes enamel?
A
Ameloblasts
4
Q
What is the only calcified tissue that does not contain collagen?
A
enamel
5
Q
What type of tissue is calcified over in dentin, cementum and bone?
A
type 1 collagen
6
Q
What makes dentin?
A
odontoblasts
7
Q
What makes cementum?
A
cementoblasts
8
Q
what comprises the periodontium?
A
gingiva
cementum
periodontal ligament
surrounding alveolar bone
9
Q
what are the only organisms that can rely solely on fermentation as their energy source?
A
microbes
10
Q
what does dental caries result from?
A
microbial fermentations that produce lactate by glycolysis from monosaccharides
11
Q
Which bacteria is referred to as sugar metabolizing?
A
saccharolytic
12
Q
which type of bacteria is non-sugar metabolizing but instead hydrolyzes proteins and utilizes amino acids for energy?
A
asaccharolytic
13
Q
What does saccharolytic bacteria lead to?
A
dental caries
14
Q
What does asaccharolytic bacteria lead to?
A
periodontal disease
15
Q
Which type of oral microbiota is predominant, and what is the major end product?
A
saccharolytic
lactic acid
16
Q
A term for teeth adherent bacterial films
A
plaque
17
Q
what is a facultative anaerobe?
A
Bacteria that uses primarily aerobic respiration but can go anaerobic if no oxygen is present
18
Q
What is an obligate anaerobe?
A
bacteria that can only use anaerobic respiration
19
Q
Difference between Gram + and Gram - bacteria
A
Gram +
3 layers with thick outer membrane (peptidoglycan)
Gram -
5 layers with a thin outer membrane (lipopolysaccharide and protein –> toxin; immunogenic)
20
Q
Which type of bacteria is predominantly found in people who keep their teeth clean and have no periodontal disease? (gram +/-)
A
Gram +
21
Q
What does whole saliva contain?
A
MUCINS- proteins covered with numerous saccharide (glycan) residues
22
Q
What type of microbiota does a repeated intake of dietary carbohydrates predispose to?
A
saccharolytic microbiota
23
Q
Why can gram + bacteria tolerate low pH caused by lactic acid production?
A
Their thick cell walls
24
Q
What does excess lactic acid do to teeth?
A
causes caries by dissolving tooth enamel and dentin
25
Where is there an intermittent flow of proteins from serum? And what is it called?
beneath a healthy gingival sulcus
| Gingival crevicular fluid
26
Which type of microbiota is better suited for what gingival crevicular fluid provides?
asaccharolytic microbiota
27
In healthy oral cavity, how do asaccharolytic bacteria digest proteins?
They secrete proteases which digest proteins to small peptides, which they digest (ferment)
28
What happens to amino acids during asaccharolytic fermentations?
AAs are deaminated to ammonia
29
What does an accumulation of ammonia in the oral cavity do?
It makes the gingival sulcus alkaline which prevents caries from developing beneath the gingival sulcus
(however it does cause a build up of calcium and phosphate)
30
What is the accumulation of calcium and phosphate called?
dental calculus
31
What happens if dental calculus is not maintained?
the buildup allows for assacharolytic metabolism to intensify
32
What is the cause of malodor?
It is from H2S.
| When sulfur-containing amino acids (cysteine and methionine) are metabolized, they release H2S and ammonia.
33
What does malodor usually accompany?
periodontal disease
34
T/F: Collagen synthesis and degradation are central to the well being of the teeth and periodontium.
True
35
What is Fibrillar collagen synthesized by?
1. Fibroblasts (extracellular matrix)
2. Chondroblasts (cartilage)
3. Osteoblasts (bone)
4. Odontoblasts (dentin)
5. Cementoblasts (cementum)
36
What are the top two contributors to the AA composition of alpha-1 chain of tropocollagen?
Glycine (33%)
| Proline (14%)
37
Main steps in Biosynthesis of Collagen
- mRNA is translated in the RER
- Selected proline and lysine residues are hydroxylated
- Selected hydroxylisine residues are glycosylated with glucose and galactose
- three pro-a chains assemble and pass through the Golgi (is not procollagen)
- procollagen is then secreted into the extracellular matrix (ECM)
- The N and C terminal propeptidases are cleaved by procollagen peptidases producing Tropocollagen
- Self-assembly of tropocollagen fibers (cross-linked) to form mature collagen fibers (via covalent crosslinking)
- collagen may be attached to cell membranes by several types of proteins such as fibronectin and integrin
38
What mutation in collagen inhibits adequate triple helix formation?
mutations of glycine residues
39
What are the oral disorders related to collagen?
Osteogenesis imperfecta- fragile bones
| Dentinogenesis imperfecta- completely missing teeth
40
Which vitamin is essential for hydroxylation?
Vitamin C (ascorbate)- is an antioxidant (reducing agent)
41
What enzyme do humans lack which makes them unable to synthesize ascorbate?
L-gulonolactone oxidase
42
Which vitamin is essential for proline and lysine hydroxylase functioning in vertebrates?
Ascorbate.
43
Why is the antioxidant property of Ascorbate important extracellularly?
Neutralizes ROS from leukocytes during inflammation
44
What is an early symptom of ascorbate deficiency?
the loss of gingival and periodontal membrane fibers accompanied by loosening of teeth
45
How often do the anchoring fibrils of the gingiva and periodontium turn over?
Every 24 hours due to tooth movements and stimulate fibroblasts to replace collagen and renew the attachment continuously
46
What develops in the absence of ascorbate?
Scurvy
47
Where is keratin found?
```
hair
wool
skin
horns
fingernails
```
48
What is keratin composed of?
a-helical polypeptides
49
parakeratinized vs nonkeratinized?
parakeratinized- (harder)
-cells of the outer surface of the hard palate and gingival mucosa (like the skin)
nonkeratinized- (softer)
-cheeks, lips, ventral surface of tongue, soft palate (are permeable to fluids and small molecules)
50
What are the hard tissues of the tooth?
enamel
| dentin
51
What is "hardness" related to in biological systems?
ability to form calcium salts
52
Does pulp demonstrate mineralization?
NO
53
what is the mineral in teeth that makes them hard?
hydroxyapatite (hydroxylapatite)
54
What is the formula of hydroxyapatite?
Ca10(PO4)6(OH)2 (very insoluble)
55
What percentage is enamel and dentin by weight mineral and protein?
Enamel- 97% mineral, less than 1% protein
| Dentin- 70% mineral and 30% protein
56
What is the function of dentin?
to support and protect
57
How is enamel formed?
Formed on an extracellular matrix.
| Ameloblasts secrete enamelin and amelogenin which is later mineralized to form enamel
58
What is the hardest substance in the body?
enamel
59
When are ameloblasts present?
only during tooth development
60
How is dentin formed?
It is formed around the pulp on an extracellular matrix of collagen and non-collagenous proteins formed by Odontoblasts
61
What is the formula for fluoroapatite and why is it beneficial?
Ca10(PO4)6F2, it is harder than hydroxyapatite
62
What does mineralization require?
scaffolding proteins
| high concentrations of ions (the ones needed particularly)
63
What is the process called of boosting the ions needed for mineralization?
nucleation
64
What is the scaffolding protein used in mineralization of dentin?
collagen (mineralizes toward the pulp)
65
What is the scaffolding protein used in the mineralization of enamel?
amelogenins (built up as crystallites), mineralizes toward the crown
66
What is saliva supersaturated with?
Ca and phosphate ions, and buffers at around pH 7
67
What does bacterial waste deposited on the tooth surface do to the pH?
lowers the pH
68
What is and what does Dentinal Fluid do?
it is exuded by odontoblasts which line the pulp cavity
| -purges the enamel of bacterial waste
69
What is the primary function of the dental pulp?
to form dentin (by the odontoblasts)
70
What is the bacterial waste from aerobic bacteria?
CO2 and water
71
What is the bacterial waste from anaerobic bacteria?
acids, eg. lactic acid
72
Finish the cascade; The deeper the plaque...
the more anaerobic, the more acid, the lower the pH
73
What is the critical pH when the enamel begins to dissolve (Demineralization)
pH 5.5
74
What does fluid flowing from the pulp through the tooth do?
helps neutralize acid and wash out wastes
75
What does Calcium and Phosphate in the saliva do?
Helps to resist the loss of mineral
76
What does Anionic Proline-Rich proteins and Statherin do?
Helps stabilize crystallites
77
What does saliva do?
helps to neutralize H+ and sets a new pH
| -also helps wash away wastes
78
T/F: Fluorapatite is less soluble than hydroxyapatite.
True, and is also more resistant to demineralization
79
Main ways to resist dental caries
-Brush and floss to minimize plaque and shift oral bacteria toward aerobic metabolism
-Minimize snacking to lower pathogenic bacteria and reduce bacterial acid production
Facilitate Dentinal Fluid effects by eating well and minimizing sugar intake
-Stimulate salivary flow by drinking adequate fluids, eating raw foods and chewing gum
80
How to incorporate fluoride to resist dental caries
- Use fluoridated toothpaste to create a CaF2 smear layer on teeth which maintains a low fluoride release through the day
- Fluoride will inhibit bacterial metabolism lowering acid excretion by plaque bacteria (inhibits enolase)
- Brush before bedtime to maximize effects during sleep when salivary flow is minimal
81
What is optimal fluoride intake?
at or less than 1 ppm
82
What is it called when you have too much fluoride intake?
fluorosis
83
How does fluoride inhibit demineralization?
Protons diffuse into the hydroxyapatite crystal
React with OH groups in hydroxyapatite and
Change the crystal to an amorphous calcium monohydrogen phosphate solid that slowly dissolves
84
How much fluoride must be ingested to become toxic?
Greater than 10ppm
85
What are the effects of fluoride poisoning?
lack of energy
| inhibits osteoblast activity more than osteoclast activity, resulting in an increased frequency of bone fractures
86
At 50-100ppm, what has fluoride been shown to do?
- to inhibit gluconeogenesis by binding Mg2+ ions that are needed to activate fructose 1,6 bisphosphatase.
- Also inhibits ROS elimination by binding iron, selenium and molybdenum ions at the respective catalytic centers of catalase, peroxidase and superoxide dismutase
87
What do stress induced bony microcracks attract?
White Blood Cells (WBCs) (monocytes)
88
Describe bone remodeling
Monocytes differentiate into osteoclasts and remove all of the bone around a microcrack, then osteoblasts lay down new bone in response to the stresses
89
In the tooth, what can and cannot be remodeled?
Cementum and dentin can be remodeled
| Enamel cannot be remodeled because ameloblasts cannot be generated
90
What is the most abundant mineral in the human body?
Calcium!!!
91
Where is calcium maintained, intracellularly, in the human body?
Calcium ions are retained in the ER or in the sarcoplasmic reticulum in muscle
92
What are the main salivary glands in the mouth?
parotid
submandibular
sublingual
93
What do acinar cells secrete?
serous (watery) fluid
94
What do tubular cells secrete?
mucous (viscous) fluid
95
Which type of cell is associated with which salivary gland?
Submandibular and sublingual glands have both acinar and tubular cells.
Parotid has only acinar cells
96
What are the components of saliva?
Water
NaCl- electrolyte
Sodium bicarbonate- stabilize tooth surface
Mucin proteins- proteoglycans that mediate viscosity
a-amylase- digests starch
Proline rich proteins
(Calcium and phosphate also present in supersaturating conditions)
97
What do salivary glands excrete which aid in buffering the acids?
ammonia
98
What does the odor or taste of food do to the saliva?
provides neuronal stimulus (activates cholinergic and adrenergic receptors) to the gland's myofibrils and this stimulates SALIVARY SECRETION
99
What is a dry oral cavity called, and what causes it?
Xerostomia
Caused by;
-loss of salivary gland due to trauma or disease
-if nasal allergies or sinus infections cause persistent mouth-breathing
-if tobacco smoking persists
100
Function of mucins
lubricate oral mucosa and food particles and inhibit bacterial colonization
101
function of Water (in saliva)
Facilitates clearance and inhibits bacterial colonization
102
function of Amylase?
Digests starch in food particles, promoting bolus cohesion
103
function of sodium bicarbonate, carbonic anhydrase and statherin in saliva?
Stabilize tooth surface
104
Function of proteins in saliva?
Form acquired enamel pellicle
105
Function of peroxidases, histatins, lysozyme and lactoferin in saliva?
Innate immunity that inhibits bacterial growth
106
Function of salivary agglutinin and mucin
Innate immunity that enhances bacterial clearance
107
Function of secretory immunoglobulin (sIgA) in saliva?
Acquired immunity that enhances bacterial clearance
108
What does periodontal disease describe?
a mixture of diseases in which the periodontal attachment is destroyed, resulting in loose teeth
109
Where does chronic periodontitis first appear?
gingival sulcus
110
Why are mouthwashes typically at a 15-20% alcohol level?
to maintain "essential oil" solubility
111
T/F: Longtime daily users of antiseptic mouthwash has been linked to an increased risk of oral cancer.
True
112
What is the downside of long time users of alcohol free mouthwashes?
interferes with taste and probiosis (protection by the good bacteria)
113
What are prostaglandins and thromboxanes and what are they derived from?
Proinflammatory eicosanoids
| Derived from linoleic acid (essential fatty acid)
114
What enzyme catalyzes the formation of prostaglandins and thromboxanes?
COX enzymes (some studies suggest that COX inhibitors might control chronic periodontitis)
115
2 examples of COX inhibitors
aspirin
| ibuprofen
116
What dietary compound has coincided with an increase in caries?
sucrose
117
What is the DMFT (Decayed Missing Filled Teeth) for daily sugar consumption?
1 DMFT for every 25g of sugar consumed daily
118
What is a material at LLU used to fill root canals?
MTA (Mineral Trioxide Aggregate)
119
What does calcium hydroxide induce when used as a pulp-capping agent or placed in the root canal in contact with healthy pulpal or periodontal tissue?
induces a calcified barrier
120
What is the pH of calcium hydroxide?
pH of 12.5
121
What derives the calcium ions that form the barrier from the use of calcium hydroxide?
The barrier is derived entirely from the bloodstream and not from the calcium hydroxide
122
Why is the hydroxyl group an important component of calcium hydroxide?
The hydroxyl group provides an alkaline environment which encourages repair and active calcification
123
Why is alkaline pH important in the oral cavity?
- neutralizes lactic acid from osteoclasts, thus preventing a dissolution of the mineral components of dentin
- activates alkaline phosphatases which play an important role in hard tissue formation
124
When using MI paste, what is the "key"
The key in remineralization of the tooth is the integrity of the tooth surface, if it remains intact, uncavitated, remineralization is possible
125
What are the two main chemical agents used in tooth whiteners?
```
carbamide peroxide
hydrogen peroxide (the active whitening ingredient)
```
126
What are the two routes of blood clot formation (hemostasis)?
Intrinsic
| Extrinsic
127
When is the inrinsic pathway instigated and when is the extrinsic pathway instigated?
Intrinsic- when blood comes into physical contact with abnormal vessel wall (slight damage from the inside)
Extrinsic- initiated by factors released from injured tissues (outside; tissue factor is revealed which normally doesn't touch the blood)
128
Describe the Final Common Pathway in the Coagulation Cascade
- Va activates Prothrombin (II) to Thrombin (IIa)
- Thrombin (IIa) activates Fibrinogen (I) to Fibrin (Ia)
- XIIIa then catalyzes Fibrin (Ia) to Cross-linked fibrin clot
129
What is hemophilia?
Genetic mutations of coagulation proteins that cause life-long excessive bleeding
130
Why are older adults predisposed to clotting?
because of blood vessel degeneration or a decreased blood flow
131
T/F: Chronic inflammation associated with chronic periodontitis enhances clotting systemically, but inhibits blood clotting locally.
True
132
What is the concern about a tooth extraction in an elderly individual?
Clots may obstruct small arteries or detach as an embolus and cause an embolism elsewhere in the body which can cause heart attack, stroke, pulmonary obstruction or peripheral necrosis
133
What are the drugs that reduce clot formation?
```
Heparin
Coumadin
Warfarin
Aspirin
Ibuprofen
```
134
What are the drugs that promote clotting?
Epsilon-aminocaproic acid
| Tranexamic acid
135
What are astringents? and what are the best astringents used in dentistry?
Astringents are substances that tend to shrink or constrict body tissues.
-Zinc, iron and aluminum salts are best in dentistry
(AlCl3 is used commonly in gingival retraction)
136
How do aluminum compounds work as hemostatic agents and astringents?
Result from its ability to precipitate protein, constrict blood vessels and extract fluid from tissues
137
What 3 mediums in particular is AlCl3 soluble in?
Water (highly)
Alcohol (freely)
Glycerin
138
What is Ferric subsulfate solution?
it is an astringent that results in agglutination of surface proteins (closes wound) on an open wound, leading to quick and efficient hemostasis
139
What type of secondary structure does keratin have?
a-helix
