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One hypothesis for root resorption not occuring is due to hertwig's root sheath, what proteins are expressed to prevent?
OPN, BMP-2, and Ameloblastin
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Formation of sealing zone of osteoclast is mediated by ______.
apatite,
need mineralized surface for resorption
cementum has unmineralized cementoid and circumpulpal dentin has predentin
-
Cementum externally and predentin internally lack what extracellular proteins containing this sequence of amino acids?
RGD; arginine-glycine-aspartic acid
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Another explanation for resistance of teeth to resorption is that factors found in predentin and cementum such as __________ or __________ act as __________ of resorptive cells.
osteoprotegerin or amelogenin,
inhibitors
-
The _________ cementum, the innermost layer of cementum, creates a barrier between the dentinal tubules and the PDL.
intermediate,
if lost allows inf mediators to progress to PDL initiating resorption
-
This B-cell transcription factor is the earliest determinant of the osteoclast lineage.
PU.1
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____ is one of the recognized markers of osteoclast precursors in human
CD11b
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Dissolution of the mineralized component of bone and cementum by osteoclasts is largely dependent on _________ of the extracellular resorption lacuna by _______ wihtin the riffles border membranes.
acidifcation
V-ATPases
-
Cytokines ___ and ____ appear to have the most profound effect on hard tissue resorption.
IL-6 and IL-11
IL-6 reduces osteoclasts ability to be inhibited by inc in extracellular Ca, so much of it is formed during resorption
-
The singular defining feature of the mature osteoclast is _______, namely the ability to _________________.
funtional
resorb calcified tissues
-
Characterisitic morphologic features of osteoclast:
ruffled border (cytoplasm undulations)
sealing zone (ventral surface of the osteoclast membrane in contact with the targeted bone)
-
What are some RGD peptide containing proteins?
OPN, BSP, FN, Vitronectin
-
Initiation of root resorption has two requirements:
1. removal or protective predentin or precementum
2. presence of noxious stimulus to start inf response.
First step in root resorption is binding of the odonto- or osteo-clast
-
After the clast binds then what?
Ruffled border formation and release of carbonic anhydrase and V-ATPase into the resorbing compartment to decalcify
-
Describe one theory for internal resorption etiology?
Coronal necrotic infected pulp provides the stimulus for inflammation in the more apical parts
Alternative theory is apoptosis of odontoblasts induce cytokines
-
Localized injury: healing with cementum
External resorption caused by an injury restricted to external root
concussion or subluxation
mechanical damage to cementum but localized
vital pulp
healing within 14 days
-
Diffuse injury: Healing by osseous replacement
External resorption caused by an injury restricted to external root
severe injury (intrusive luxation or avulsion with extended dry time)
more than 20% of root surface
precursors of bone not PDL repopulate injury
dentoalveolar ankylosis (becomes part of bone-remodeling)
-
Name 5 treatment strategies to avoid or minimize osseous replacement resorption
- 1. prevent initial injury
- 2. minimize additional damage
- 3. pharmacologic interventions
- 4. stimulation of cementum rather than osseous
- 5. reduce rate of osseous replacement
-
Four general types of inflammatory stimulus that cause external root resorption?
- 1. pressure
- 2. microbial infection of cana or periodontal sulcus
- 3. sulcular infection
- 4. chemical damage secondary to bleaching
-
What is perapical replacement resorption?
coined by Bender 1997
apical resorption when predentin is affected in ortho movement
-
What treatment factors can be attributed to OIRR (ortho induced infla root resorption)?
- 1. Duration
- 2. Magnitude of force (use intermittent)
- 3. Direction of tooth movement (intrusive and lingual torque > bodily, extrusive, lingual tipping)
- 4. Method of movement
-
What patient factors can be attributed to OIRR?
- 1. Short roots or previous signs of root resorption
- 2. Endo teeth more resistant
- 3. Genetic predisposition (homo for IL1B allele 1, 5.6 times greater risk)
Halt tx for 2-3 months with passive archwires
-
Pulp space infection can lead to external root resorption in either the ________ or ________ regions of the root.
apical (apical periodontitis)
Lateral (damaged cemental covering during severe trauma)
-
The microbial profile of a traumatized necrotic pulp should resemble that of a primary endo infection with upward of ___ CFUs and more than __ strains.
107
80
-
The two major tx principles are _______ of pulp space infection and _________ of any bacteria in the pulp space.
prevention
elimination
-
Success of revascularization of open apex soaked in doxycycline for 5 mins?
50%
-
At present, the dx tools cannot detect a vital pulp until approx _ months following successful revascularization.
6
possible to lose tooth to resorption if not known sooner that tooth was acually not revitalizing
LDF can detect as soon as 4 weeks
-
Closed apex and trauma, how soon endo?
within 7-10 days of trauma
hard to do so CaOH, 1 month PDL heals, then endo, can be done for up to 6 months
-
What is coined "pink spot"?
Subepithelial inflammatory resorption
long-standing resorption gives rise to granulation tissue which undermines the enamel of the crown
-
Predisposing factors for cervical resorption?
- 1. Trauma
- 2. Orthodontics
- 3. Intracoronal bleaching
- 4. dentoalveolar surgery
- 5. period disease or treatment
-
It has been postulated that _______ in the sulcus of the tooth stimulate and sustain an inflammatory response leading to subepithelial infl root resorp.
bacteria
-
Approx __% of cervical resorption was attributed to bleaching.
4
-
In cervical root resorption does the lesion pierce the canal?
No, not normally, tooth is vital.
Pulp can be outline through the defect
-
What did Friedman 1988 find?
58 teeth with 30% hydrogen peroxide, 7% developed cervical resorption
-
Holmstrup 1988?
Follow up study to Friedman, found no cervical resorption when using sodium perborate in water
-
What can contribute to cervical resorption due to IB?
- 1. hx of traumatic injury
- 2. application of heat
- 3. acidity of external root environment adjacent to the application of bleaching agent
-
Classification of internal root resorption?
Apical or Intraradicular
-
Two hypotheses for internal resorption etiology?
1. infected coronal pulp leads to adjacent granulation tissue
2. granulation tissue if nonpulpal origin, from vascular compartment or PDL
-
Internal root resorption only takes place when?
Odontoblastic and predentin layer are damaged (lost or altered)
-
Systemic diseases and root resorption?
Renal dystrophy: inc oxylate concentration
Hyperparathyroidism
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