Liana_tooth development & EMD Flashcards
What forms from the 1st Pharyngeal arch and pouch?
This is probably the most important arch and pouch.
1st arch:
* Mandible and maxilla
* Meckel’s cartilage (incus and malleus)
* Ligaments (Sphenomalleolar, sphenomandibular)
* Muscles of mastication
1st pouch:
* Tympanic membrane and cavity
* Mastoid antrum
* Eustachian tube
What forms from the 2nd arch and pouch?
CARTILAGE, BONE, MUSCLE
2nd Arch:
* Reichert’s cartilage
* Lesser horns and upper body of hyoid bone
* Muscles of facial expression
* Stapes of inner ear
2nd pouch:
* disappears, but contributes to the palatine tonsils
What forms from the 3rd pharyngeal arch and pouch? BONE AND GLANDS
3rd Arch:
* Greater horns and lower body of the hyoid bone
3rd Pouch:
* Inferior parathyroid gland
* Thymus
What forms from the 4th pharyngeal arch and pouch?
CARTILAGE AND GLANDS
4th arch:
* Cartilages of the larynx
4th pouch:
* Superior parathyroid
* Thyroid gland
What forms from the 5th and 6th pharyngeal arches and pouches?
Nothing - they disappear
What are the stages of tooth development, and when do they occur?
Remember 6, 8, 10, 12 weeks (for development stages)
Placode, Bud, cap, bell
* Placode (thickening) : 6 weeks in utero
* Bud: 8 weeks in utero
* Cap: 10 weeks in utero (morphodifferentiation)
* Bell: 12 weeks in utero (histodifferentiation)
What is EMD and what are the components of it?
EMD: The purified fraction of the enamel layer of developing porcine tooth buds
Composition: ~90% amelogenins, and 10% tuftelins, proline-rich non-amelogenins, serum proteins, etc
What study suggested that EMD forms acellular extrinsic fiber cementum in monkeys?
Hammarstrom ‘97
2 aims:
1- to identify enamel protein (Amelogenin) expression around the developing roots of rat molars and human premolars –> proved
2- To show that porcine EMD is important for cementum formation: extracted incisors in Monkeys –> removed cementum layer and superficial dentin layer –> cavities preped and filled with EMD –> HISTOLOGY showed cavities with EMD were filled with Acellular Cementum that was tightly attached to underlying Dentin (Control cavities were filled with loosely attached hard tissue)
What are the steps to use EMD? How much does it cost?
- Prepare the root surface (access, SRP, apply PrefGel 24% EDTA for 2 minutes) and irrigate
- Confirm Hemostasis
- Apply on the complete wound area and wound margins, including the exposed bone, right before final flap closure.
Cost: $141.75 per syringe
Name some studies discussing EMD and SRP
Wennstrom & Lindhe ‘02: No differences in PD (SRP + EDTA versus SRP + EDTA + EMD).
Roccuzzo ‘22: No long-term differences in CAL or PD when using EMD in SRP. In the short term, EMD might reduce BOP.
How does EMD affect GTR in intrabony defects? Name a few studies
Sculean ‘08: 10 year study. No difference between EMD + GTR and GTR only. CAL gain was 2.8 for both groups. (OFD was 1.8mm)
Nibali ‘20: GTR and EMD had similar outcomes in CAL gain and PD reduction
2014 AAP Regeneration Workshop: In intrabony (contained) defects, biologics (EMD, rhPDGF, Beta-TCP) are similar to using GTR with dFDBA. Both are better than just OFD.
Does EMD affect regeneration in furcations?
Jepsen ‘04: Multicenter RCT comparing EMD vs. membrane in GTR of Class II mandibular furcation defects.
* EMD: Horizontal reduction of 3mm and less postoperative swelling
* Membrane: horizontal reduction of 2 mm
2014 AAP Regeneration workshop: Consensus statement: Regeneration is an option for most furcation defects, especially Class II furcations. Consider using combinations of barrier membranes, bone grafts, and biologics for better outcomes.
Do biologics help with alveolar ridge augmentation?
Suarez-Lopez del Amo & Monje ‘22: Similar outcomes when using biologics vs. no biologics.
Systematic Review Best Evidence
Does EMD benefit in recession coverage procedures?
Possibly, but it is of minimal benefit.
Carvelli ‘22: Systematic review & meta-analysis. EMD improved root coverage by about 0.3 mm (when added to CAF & CTG)
McGuire ‘16: In the EMD + CAF group: some regeneration was found. In the CTG + CAF group (after 9 months), no regeneration was found
MORE DETAILS FROM McGuire 2016
“Methods: Three patients, each requiring extraction of four premolars before orthodontic treatment, were enrolled in a randomized, open-label study. Two months after induction of Miller Class I and II GR, each patient received EMD+CAF for three teeth and CTG+CAF for one tooth for root coverage. Nine months after root coverage, all four premolars from each of the three patients were surgically extracted en bloc for histologic and microcomputed tomography (micro-CT) analysis, looking for evidence of periodontal regeneration. Standard clinical measurements, radiographs, and intraoral photographs were taken over prescribed time points.
Results: Seven of the nine teeth treated with EMD+CAF demonstrated varying degrees of periodontal regeneration, detailed through histology with new bone, cementum, and inserting fibers. Micro-CT corroborated these findings. None of the three teeth treated with CTG+CAF showed periodontal regeneration. Clinical measurements were comparable for both treatments. One instance of root resorption and ankylosis was noted with EMD+CAF.
Conclusions: EMD+CAF continues to show histologic evidence of periodontal regeneration”
Does EMD benefit peri-implantitis treatments?
It is inconclusive; Few studies currently exist on this topic.
