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Treatment Planning Notes > guided tissue regeneration > Flashcards

guided tissue regeneration Flashcards

1
Q

how to determine true perio regeneration

A

-histology (not practical)
-CAL gain
-PD reduction
-recession
-bone fill (radiographically or direct inspection)

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2
Q

which bone grafts have been supported to have regen histologically?

A

autogeneous bone and DFDBA support formation of new attachment apparatus histologically

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3
Q

alloplastic grafts for regen

A

Histological evidence indicates that alloplastic grafts support periodontal repair rather than regeneration

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4
Q

how deep should the intrabony defect be to benefit from GTR?

A

(Laurell 1998):
at least 4 mm deep, based on the fact that you get some bone fill (1.1mm) but there is crestal resorption (1mm)

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5
Q

how much change in perio parameters do you expect with GTR +/- bone graft

A

-Laurell 1998:
-no study achieved 100% regeneration
-CAL gain to around 80% of the defect
-PD reduction from 3.4-8.5 mm
-CAL gain of 4.2 mm (N=545)
-Defect fill of 3.2 mm (N=364)

Simple regression analysis = correlation between defect depth and CAL gain/bone fill with large regression coefficient.

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6
Q

non-resorbable vs bioabsorbable barriers

A

Laurell 1998: No difference

Murphy and Gunsolley 2003: no difference

Caffesse: no difference

Kinaia: absorbable > non absorbable for vertical bone fill (slightly better but not sig)

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7
Q

GTR versus OFD for intrabony defects

A

(Murphy and Gunsolley 2003, Needleman 2006 Cochrane)
-greater CAL and PD reduction

According to Cortellini et al., (2017), OFD resulted in a higher risk for disease recurrence compared to regenerative procedures over a 20-year period

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8
Q

GTR versus OFD for furcation defects

A

Murphy and Gunsolley: GTR> OFD
-improved CAL and PD, esp if GTR+bone

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9
Q

GTR versus GTR+bone for intrabony defects

A

(Murphy and Gunsolley 2003):
-use of bone did not enhace regen

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10
Q

effect of membrane exposure on regen

A

(Machtei 2001, meta analysis)
-major effect on implants but less for teeth
-sig diff with exposed membrane but not clinically sig
-minimal effect on GTR

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11
Q

compare EMD to GTR to OFD

A

Tu 2010:
-EMD >OFD

Esposito 2009 Cochrane review:
-GTR = EMD, but more post op complications with GTR

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12
Q

EMD versus EMD+bone/membrane

A

Tu 2010 meta analysis:
-EMD > OFD
-no additional benefits of combination
-EMD+bone had 1.10mm more infrabony defect fill than EMD alone
-in terms of type of bone, BioOss had greater benefit

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13
Q

What is the grading system for CEPs

A

Masters, Hoskins 1964
Grade I: distinct change projecting towards the furcation,
Grade II: approaching the entrance but not in the furcation proper,
Grade III: extending into the furcation proper.

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14
Q

prevalence of CEPs in mand and max teeth

A

Masters, Hoskins 1964
28.6% mandibular
17% maxillary

90% of molars with furcation involvement have CEPs

Swan and Hurt
32.6% overall
mand M: 33.7%
max M: 31.4%

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15
Q

use of antibiotics for regeneration?

A

Heitz-Mayfield 2009:
-Prevent post-surgical infection (especially if membrane exposure occurs), optimize potential for regeneration
-Studies with EMD have found NO added benefit with antibiotics

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16
Q

which teeth are affected by CEPs according to Swan and Hurt

A

-mand 2nd M (51% prevalence) (they are usually Grade 1 and on buccal)

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17
Q

prevalence of IBR in mand 1stM

A

(Everett) 73%
(Dunlap and Gher) 70%

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18
Q

what are highly associated with IBRs

A

(Hou and Tsai)
CEPs (63%) and class 3 furcations (25%)

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19
Q

how many isolated furcation involvements are associated with CEPs? (Hou and Tsai)

A

prevalence of 63.2% furcation defects with CEPs and IBRs

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20
Q

incidence of a CEP Grade III

A

4.3% (Masters and Hoskins 1964)

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21
Q

How do CEPs affect periodontal treatment

A

-Enamel prevents attachment of the PDL fibers
- leads to a deep pocket and lower attachment and furcation involvement
-Susceptible to plaque accumulation and affects plaque removal
-Complicates SRP

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22
Q

What is the width of the furcation entrance

A

Bower 1979
In 81% of the furcation of maxillary and mandibular molars the entrance was found to be 1.0mm or less and in 58% it was 0.75mm or less

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23
Q

location of root furcation from CEJ in mand 2nd molars

A

Mandelaris: 3.09mm

24
Q

4 different cell types that can repopulate root surface after periodontal surgery

A

-epi, CT, bone, and PDL

25
Q

Define GTR

A

A surgical procedure with the goal of achieving new bone, cementum, and periodontal ligament (PDL) attachment to a periodontally diseased tooth, using membranes to provide space maintenance, epithelial exclusion, and wound stabilization.

26
Q

Regeneration versus repair

A

Regeneration refers to restoration of architecture and function through the reconstitution of new periodontium by PDL cells (bone, PDL, cementum)

  • repair: does not fully restore the architecture or function (long junctional epithelium, resorption, and ankylosis)
27
Q

New attachment

A

The union of connective tissue or epithelium with root surface that has been deprived of its original attachment apparatus. This new attachment may be epithelial adhesion and/or connective adaptation or attachment and may include new cementum.

28
Q

Why is regeneration better than repair

A
  • restores the natural architecture and function
    -Repair results in nonfunctional scar tissue, which has a questionable long-term stability
    -Root resorption may also result as a form of repair, which harms the tooth.
29
Q

What are your goals for GTR?

A

-Increase in attachment
-Increase in bone
-Decrease in PD
-Minimal increase in recession
-Furcation closure!
-Tooth survival

30
Q

Can you have regeneration on root surfaces that previously harboured plaque?

A

-Gottlow 1984 proved that if you scaled roots, used a Millipore filter, you can get regeneration

31
Q

When do you decide to treat a defect with GTR?

A

-Cortellini and tonetti 2000: deeper defects (more than 3mm) benefit the most, getting superior CAL gains than shallower defects
-Tonetti: defects <25 degrees had more attachment than >37 deg regenerative therapy

32
Q

Which factors influence the success of periodontal regenerative therapy?

A

-Patient factors: OH compliance, maintenance compliance, smoking
-Tooth factors :Endo status, mobility status, restorative status
-Defect factors: Bony walls present, furcation involvement, depth, width
-Surgical factors: bioexclusion, space creation, clot stabilization, primary closure, passive flap closure, mobility, tissue thickness

33
Q

Why is passive flap closure important?

A

(Hiatt) tensile strength of tooth-gingival flap interface increases between day 3 to day 5-7 post surgery seen in dogs, and even at 2 weeks post surgery of limited periodontal surgical wound. This wound may NOT reach functional integrity until 2 weeks post surgery. So wound integrity during early phases (at least 2 weeks) depends on stabilization of flaps by 1) good suturing (material, placement, and removal) and 2) post op instructions (OH, and bacterial colonization)

34
Q

Bioexclusion

A

Using a barrier membrane to prevent epithelial migration, which then favors the repopulation of PDL cells and perivascular cells to differentiate into cementoblasts, fibroblasts, and osteoblasts, form the alveolar bone, PDL, and cementum

35
Q
  • Is DFDBA superior to FDBA?
A

-DFDBA may potentially have osteoinductive properties as well due to BMPs
-Bowers et al: histologically verified true periodontal regeneration at intrabony defects using DFDBA
-Rummelhart 1989: no difference between FDBA and DFDBA
-2015 AAP consensus: concluded that DFDBA had the best body of evidence to support it as a predictable material for regeneration

36
Q

Does commercially available DFDBA contain enough active BMP?

A

-it is unpredictable due to:
-BMPs at low levels to produce bone formation
-BMPs present but inactive
-some batches has more BMPs than others based on the donor (esp age)
-sterilization may have an effect
-bone bank preparations bary
-larger particle size have more osteogenic potential

37
Q

Is there a high risk of disease transmission with allografts?

A

-Mellonig 1992: treatment of DFDBA successfully inactivates HIV

38
Q

What is the mechanism of action of EMDs?

A

EMD is enamel matrix derivative that is a mixture of proteins, mainly amelogenin, that mimics the events that occur during root development and to help stimulate periodontal regeneration
-the Hertwig’s epithelial root sheath releases EMPs
HERS disintegrates
mesenchymal cells are exposed to the dentin and EMPs, they are induced to become cementoblasts and form the acellular cementum layer, which is required for the formation of the PDL and alveolar bone

Emdogain comes from porcine unerupted tooth buds

39
Q

Hamp Classification: (horizontal measurement)

A

F1: probe can penetrate furcation < 3mm
F2: probe >3mm but not through and through
F3: through and through furcation involvement

40
Q

Glickman Classification:

A

Grade 1: incipient suprabony lesion
Grade 2: loss of interradicular bone, but a portion remains intact
Grade 3: through and through (no bone attached at fornix); not clinically visible
Grade 4: through and through lesion; clinically visible; soft tissue has receded apically

41
Q

Tarnow and Fletcher classification: subclassification of Glickman: *measures VERTICAL probing depth from the roof of the furcation

A

A: 0-3mm
B: 4-6mm
C: >7mm

42
Q

how often do you get furcation closure in Grade II furcations with GTR

A

Bowers: bone+membrane 2003
-Complete closure in 74%
-68% of remaining were reduced to Class I.
-those 4mm or less horizontal bone loss had better outcome
-poor outcomes:
-increases in the distance between the roof of furcation and crest of bone, roof of furcation and base of defect, depth of horizontal defect, and divergence of roots (3mm or less)

43
Q

EMD in furcations

A

-Jepsen
-EMD had greater reduction in furcation depth and lower post op swelling and pain compared to barrier

44
Q

what is the relationship between CEP and furcation

A

CEP inhibits CT attachment and makes management of furcation difficult
CEP 2 and 3 are associated with furca but not CEP 1 (Swan and Hurt)

45
Q

indications for emdogain

A

-regeneration
-furcation defects
-root coverage
-wound healing
-peri-implantitis

46
Q

what are some bioactive agents used in regeneration

A

-PDGF
-fibroblasts GF
-BMPs
-EMD
-PRP
-PRF

47
Q

what is the significance of BMPs

A

-they are glycoproteins and osteinductive
-they start a cycle of events resulting in differentiation of cells involved in perio regeneration
-they enhance bone and cementum formation

48
Q

what is the significance of rhPDGF-BB

A

bind to specific receptors on cells and initiate signaling pathways leading to cell migration and chemotaxis and cell proliferation of osteoblasts, PDL fibroblasts, and cementoblasts

49
Q

are biologics effective in tx intrabony defects

A

AAP regeneration workshop: EMD and rhPDGF-BB w B-TCP are effective in regenerating

50
Q

what is the significance of root conditioning

A

-it is believed that exposure of collagen in dentin would facilitate adhesion of blood clot to the root
-no sig effect of root tx has been found on CAL and PD. no clinical benefit

51
Q

is emdogain safe

A

-The EMPs are highly conserved among mammalian species
-exposure to these proteins takes place during tooth development in early childhood
-Thus, these proteins should be recognized by the immune system as “self” proteins
-only very high concentrations of EMD induced only a slight increase in lymphocytes

52
Q

Regeneration for intrabony defects

A

AAP 2015 workshop (Kao)
-biologics = DFDBA = GTR > OFD
-no sig difference between EMD and GTR (but in situations where wall containment is poor, barrier may be beneficial)
-no benefit of EMD with barrier
-histologic evidence of regen is seen with EMD combos, improved outcomes with EMD +bone (enhanced synergistic effects)
-EMD +- bone is comparable with GTR

Tu
-EMD alone and with bone or membrane have similar results
- but EMD+bone had more defect fill

AAP Consensus statement by Avila-Ortiz 2022
-rhPDGF and PRF are superior to EMD
-combo therapies (bone+EMD or bone+barrier) are most effective
-EMD doesnt need a barrier if contained (combined use may prevent benefit of EMD and chemotaxis)
-allogenic and xeno > autogenous and synthetic

53
Q

survival rate of GTR

A

Huynh-Ba
-GTR had the highest survival rate (83-100%) after 5-12 years

Cortellini and Tonetti: 96% after 8years (89% for smokers and 100% for non-smokers)

54
Q

when is regeneration evident with EMD

A

-Kao
-after 2-6 weeks, regeneration is evident
-after 6m, clinical improvements are noted
-post op antibiotics nor EDTA improved clinical outcomes

55
Q

benefit of having biologic

A

-promotion and acceleration of healing and regeneration
-reduced risk of postoperative complications
-improved treatment outcomes
-improved handling of bone
-can be minimaly invasive and avoid large elevated flaps for membranes

57
Q

OFD versus GTR for furcations

A

Jepsen, Murphy and Gunsolley, Kinaia
-GTR>OFD

Chen:
-GTR+bone was most effective for furcation closure

Treatment Planning Notes (15 decks)

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