Perio Flashcards
Describe regeneration cascade of bone
Inflammation; blood clot
Fibroplasia; granulation tissue
Mineralisation; woven bone
Remodelling; lamellar bone
What does bone regeneration depend on?
Signalling molecules
- cytokines
- prostaglandins, leukotrienes
- growth factors
- hormones
What is req. for successful bone regeneration?
Cells: osteoprogenitor + inflammatory Scaffold: blood clot Blood supply Signalling molecules Mechanical stability
Define biomaterial
NIH: A substance or combination of substances, synthetic or natural, which can be used for any period of time, which augments or replaces partially/totally a lost tissue/organ/function in order to maintain/improve QoL
Define: biocompatible, biotolerable, bioinert, bioactive, biodegradable
Biocompatible: no toxic/immunological response when exposed to host
Biotolerable: way in which tolerated materials are separated from host tissue by formation of fibrous tissue
Bioinert: no chemical reaction + tolerated (doesn’t exist)
Bioactive: materials that can form chemical bonds w/ bone
- bone tissue connnects to material promoting coating by bone cells
Biodegradable: degrade/solubilise/absorb over T when in contact w/ body
Describe osteogenesis
New bone synthesis by donor cells derived from either host/graft material
Cells: mesenchymal stem cells, osteoblasts/cytes
Transplants: autologous iliac bone, marrow grafts
Describe osteoinduction
Bone formation by differentiation of local uncommitted connective tissues -> bone-forming cells under influence of 1/+ inducing agents
Moderated by:
- GFs: platelet derived factor, bone morphogenetic proteins
- interleukins
- fibroblast GF
- angiogenic factors: vascular endothelial GF
Transplants: demineralised bone matrix, autologous bone grafts
Describe osteoconduction
Implanted scaffold passively allows ingrowth of host capillaries, perivascular tissue + mesenchymal stem cells
Microscopically: similar structure to cancellous bone
Transplants: all
Ideal properties of bone graft material
Osteogenic, osteoinductive, osteoconductive Structurally similar to bone Angiogenicity Nontoxic, non-antigenic Optimal mechanical properties Readily + sufficiently available Resistant to infection Min. surgical procedure + min. post-op sequalea Predictable Completely replaced by host bone of same quantity + quality Cost effective Easy to use + manipulate
Types of bone grafts
Autograft: same individual
Allograft: different individual, same species
Xenograft: different species
Alloplastic: synthetic
What factors may impact incorporation of graft?
Vascularity Infection Foreign material Malnutrition Drugs/Systemic condition
Discuss autografts
IO/EO harvesting sites
Forms: particulated, bone blocks
Origin
- intramembranous
- endochondral
Differences b/w cancellous + cortical autograft
Cortical
- excellent structural integrity + mechanical properties
- limited osteoblasts/cytes + progenitor cells
— = low osteogenic/inductive potential
- slower to incorporate cf cancellous
Cancellous
- high conc. osteoblasts/cytes = better osteogenic potential
- large trabecular surface encourages revascularisation
- little mechanical support
Dis/adv of autografts
Adv
- gold standard: osteogenic/inductive/conductive
- biocompatible
Disadv
- 2 surgeries
- inc. op T
- limited quantity
- donor site morbidity: infection, pain, cosmetic
Discuss allografts
Forms: cortical, cancellous, highly processed bone derivatives
Osteoinductive/conductive Antigenicity risk red. by - freezing - radiation - chemicals
Discuss different types of allografts
Fresh Bone
- highly antigenic
- limited T to test immunogenicity/diseases
Fresh-frozen Bone
- less antigenic
- stored -80°
- preserves biomechanical properties
- red. risk disease transmission; donor screening, aseptic processing
De/mineralised Freeze-Dried Bone
- red. antigenic
- protein alterations = red. mechanical properties
- demineralised: inc. bone morphogenetic proteins = more osteoinductive potential
Dis/adv of allografts
Adv
- unlimited quantity
- no donor site morbidity
- red. surgical T
Disadv
- risk: rejection, disease
- ethical + religious concerns
- red. osteogenic/inductive properties
Discuss xenografts
Processed to make less antigenic + prevent infection -> lose osteogenic/inductive potential
Forms: particulated, bone blocks
Sources: bovine, porcine, equine, natural coral
Discuss demineralised bovine bone mineral
Xenograft
Bovine bone processed to natural bone w/o organic component
HA skeleton retains microporous/macroporous structure of cortical/cancellous bone
Chemical + physically similar to human mineral matrix
V low resorption rate
Safety: proteins removed, 100% crystalline HA
Dis/adv of xenografts
Adv
- similar structure, chemistry, porosity cf human bone
- unlimited quantity
- short surgical T
- no donor site morbidity
Disadv
- may remain in defect for years
- mainly osteoconductive
- ethical + religious concerns
- risk disease
Discuss alloplastic grafts
Variety textures, sizes, shapes
Forms: crystalline, amorphous
Non/resorbable
Materials
- calcium sulphate/phosphate
- polymers
- synthetic HA
- bioactive glasses
Dis/adv of alloplastic grafts
Adv
- no disease transmission
- short surgical T
- no donor site morbidity
- unlimited quantity
- biocompatible
Disadv
- only osteoconductive
- remain in defect for years
Why are membranes req. for bone regeneration?
Prevent ingrowth of epithelial cells thus allowing time for bone + PDL to re-establish
Principles for successful bone regeneration
PASS Primary wound closure - membrane must not be exposed - red. mechanical + infection insult - red. epithelialisation + collagen contraction
Angiogenesis
Space Creation + Maintenance
- bone substitutes for space maintenance
- autograft gold standard to avoid collapse of membrane
Stability of wound
- initial adhesion of blood clot to defect + wound stabilisation crucial
- acts as scaffold rich in growth factors
Ideal properties of membrane material
Biocompatible
Biological activity; actively promote bone regeneration
Easy handling
Space making + maintaining
Cell occlusion/porosity: prevent down growth of tissue but allow nutrients through
Biodegradable: no 2nd surgery
Red. complications
Compare properties of non/resorbable membranes
Non-resorbable
- biocompatible
- biologically active
- space making + maintaining
- cell occlusion/porosity
- poor handling
- req. 2nd surgery
- if exposed will become infected
Resorbable
- biocompatible
- biologically active
- easy handling
- cell occlusion/porosity
- less infection risk
- no 2nd surgery
- poor mechanical properties; req. bone graft
Types of resorbable membranes
Polymer
Collagen
- non-cross linked
- cross linked
Discuss polymer membranes
Aliphatic polyesters
Excellent biocompatibility + controllable biodegradation
Low rigidity
Drug encapsulating ability
Degradation products may give inflammatory foreign body reaction
Discuss non/cross linked collagen membranes
Non-cross linked
- T1 + 3 collagen
- good vascularisation, biodegrade w/o foreign body reaction
- lack space maintaining properties + poor mechanical strength
- degradation T caries; 4d-6wk
Cross-linked
- glutaraldehyde most common chemical cross linker
- prolongs degradation T + enhance tensile strength
- indirect relationship b/w level of cross linking and tissue integration + neoangiogenesis
What are bioactive factors?
Natural mediators of tissue repair capable of eliciting a response from a living tissue/organism/cell
- osteoblasts differentiation
- angiogenesis
Growth factors
Enamel matrix derivatives
Autologous platelet concentrations
What restorative problems are associated w/ perio?
High lip/smile line Recession + Black triangles Drifting + Rotation Mobility Occlusal stability + OE Crown prep onto dentine Able to produce aesthetic pros restoration?
Discuss aetiology + Mx of recession and black triangles
Aetiology
- gingival recession post-inflammation/restoration/surgery
- inc. risk: triangular teeth, thin gingival biotype
- inc. embrasure space, inc. risk imp locking + tearing
My: make aware before occur
- accept
- comp additions/crowns; move contacts apical, teeth more square
- gingival veneers; poor compliance
- long pontics when replacing teeth
Discuss drifting + rotation of teeth
Aetiology: loss of PD support
Problem
- loss of pros space
- may make bridge/denture path challenging
Mx
- ortho: if PD stable
- XLA: move out arch or lip/tongue balance
Discuss mobility
Aetiology: loss of PD support
1ry trauma from occlusion: overloading on intact periodontium
2ry trauma: overloading on red. periodontium
Problems
- challenge for conventional imps
- accuracy of CoCr framework
Discuss OE
Aetiology: loss of opposing tooth Freq.: 83% Inc. risk - post. > ant. - Mx. > Md
Discuss splinting teeth
Indications
- improve pt comfort + function
- prevent drifting
- temp. during PD regenerative surgery
Materials
- ortho wire
- fibre-reinforced comp
- comp: freq. repair + maintenance
- cast metal
Close maintenance req.; debonds freq.
Define mucogingival deformity
Deviation from normal dimension + morphology relationship b/w gingiva + alveolar mucosa
Types of mucogingival deformities
Lack of keratinised gingiva
Dec. vestibular depth
Aberrant frenum
Gingival recession
Types of PD plastic surgery
Frenectomy Alveolar ridge preservation Crown lengthening Keratinised attached gingiva augmentation Ectopic tooth eruption Papilla regeneration
Causes of red. keratinised attached gingiva
Recession
Pocketing
Abnormal frenum pull
Define gingival recession
Apical shift of soft-tissue w/ respect to CEJ
Aetiology of recession
Mechanical: brushing, self inflicted trauma Plaque induced inflammation PD: post-Tx Iatrogenic - ortho: 5-12% within 12/12 - tongue piercings - overhangs - clasps - suboptimal crown margins
Risk factors for recession
Root prominence / B displacement / rotation
Thin gingiva + red. KAG
Thin underlying bone
High/excessive frenum pull
Cairo classification of recession
Interproximal CEJ visible; Proximal Attachment Loss
I: N; N
II: Y; < B attachment loss
III: Y; > B attachment loss
Miller classification of recession
Recession; Proximal Bone Loss; Root Coverage
I: < mucogingival junction; N; 100%
II: >/= mucogingival junction; N; 100%
III: >/= mucogingival junction; Y or displacement; partial
IV: >/= mucogingival junction; Severe; 0%
Three types of gingival phenotype
Thick flat
Thick scalloped
Thin scalloped
Compare three gingival phenotypes
Thick flat
- thick fibrotic gingiva
- thick alveolar bone
- square teeth
- large contact points
- pronounced cervical convexity
- broad zone KT
Thick scalloped
- thick fibrotic gingiva
- slender teeth
- pronounced gingival scalloping
- narrower zone KT
Thin scalloped: probe visible through crevice
- thin gingiva
- thin alveolar bone
- slender teeth
- contact points coronal
- subtle cervical convexity
- narrow zone KT
Classification of cervical lesions
CEJ A -: CEJ detectable w/o step
CEJ A +: CEJ detectable w/ step
CEJ B -: CEJ detectable w/o step
CEJ B +: CEJ detectable w/ step
Significance of steps in Tx planning
Red. Tx stability + predictability
Indications for recession Tx
Cosmetic concern Tooth/teeth sensitivity Gingival sensitivity when brushing Root caries Progressively inc. recession defect
Success criteria for Tx recession
Gingival margin on CEJ (Class I/II)
Inc. KAG
POD<3mm; BOP=0%
No hypersensitivity
Good aesthetics (colour + contour match)
Cost effective
How many recession defects will achieve 100% root coverage?
67% success rate
Describe healing of free gingival graft
Plasmatic circulation: 0-3d
Revascularisation: 2-11d
Remodelling: 11-42d
Most predictable Tx modality for recession defect
Coronally advanced flap + connective tissue graft
Difference between free gingival graft and connective tissue graft
FGG: depth 2-3mm - palate CTG: deeper than FGG, from CT layer (no epithelialised tissue) - palatal P/M - retromolar / edentulous ridge - palatal flap
Define perio-endo lesion
Combined lesion involving inflammation of lateral (PD) and PA tissues
Inflammatory products found in varying degrees in both PD tissue + pulp
Pathways between pulp + PD tissue
Anatomical
- apical foremen
- lat + accessory canals
- dentinal tubules
Non-Physiological
- iatrogenic root perforation; RCT, post + core
- vertical root #
- poor RCT
- poor restorations
Classification of perio-endo lesions (Simon, Glick, Frank 1972)
1ry endo: inflammatory process in PD tissues resulting from noxious agents present in RC
1ry perio: inflammatory process in pulpal tissues resulting from accumulation of plaque on root surfaces
True-combined: PD + endo developing independently + progress concurrently which meet and merge at point along root surface
Iatrogenic: usually endo lesions prod. by Tx modality
In EPF 2017 classification of EPL what are the subgroups?
EPL w/ Root Damage: often painful
- root #
- root perforation
- external root resorption
EPL w/o Root Damage
- PD pt: usually asymptomatic
- non-PD pt
Types of external root resorption seen w/ EPL
Progressive inflammatory
- Tx: removal of inflamed pulp + RCT
Invasive (non-inflammatory)
- Tx: complete removal/inactivation of resorptive tissues
Replacement (non-inflammatory)
- poor prognosis
- osteoclast/blast activity resorb root + replace w/ bone
What are the grades for EPL w/o root damage?
For both non/PD pts
Grade 1: narrow, deep pocket, 1 surface
Grade 2: wide, deep pocket, 1 surface
Grade 3: deep pocket, >1 surface
Define periodontal abscess
Localised accumulation of pus within gingival wall of PPD w/ express PD breakdown occurring during limited T period + easily detectable clinical symptoms
Importance of periodontal abscess
7-14% of dental emergencies
Rapid destruction of PD tissue + risk factor for exfoliation
Systemic consequences
Classification of PD abscess 2017
PD pt
- acute exacerbation
- post-Tx
Non-PD pt
- impaction
- harmful habits
- ortho
- gingival enlargement
- alteration to root surface
Subgroups of PD abscesses for PD pt
Acute exacerbation
- unTx PD
- non responsive to Tx
- supportive PD therapy
Post-Tx
- post-scale
- post-surgery
- post-medications
Subgroups of PD abscesses for non-PD pt
Impaction: floss, toothpick, ortho elastic, popcorn, rubber dam
Harmful habits: nail/wire biting, clenching
Orthodontic: forces, X-bite
Gingival enlargement
Alteration to root surface
- severe anatomic alteration: invaginated, dens evaginates, odontodysplasia
- minor anatomic: cemental tear, enamel pearls, grooves
- iatrogenic: perforation
- severe root damage: fissure, #, cracked tooth syndrome
- external root resorption
Hx and clinical signs of PD abscess
Hx
- pain
- tender gingiva
- swelling
- elevated tooth
Clinical
- ovoid gingival elevation near root
- suppuration
- deep PPD
- BOP
- inc. mobility
- systemic signs
- PD
Prognosis of EPLs
Generally poor
> perio = worse
> T = worse
1ry endo: better cf 1ry perio - worse w/ 2ry perio 1ry perio: poor - worse w/ apical involvement True combined - poor/hopeless - dependent on efficacy of perio Tx
General Mx EPL
Acute symptoms: pain, swelling, pus
Re-evaluate
Endo Tx
- inhibits PD contamination
- Ca(OH)2: bactericidal, proteolytic, anti-inflammatory = favour repair
- obturation good healing prognosis
Perio Tx
- remove noxious stimuli + allows 2ry remineralisation of dentine tubules = pulpal hypersensitivity resolves
- pulpal inflammation irreversible: RCT -> perio Tx
Review 4-6/12: healing PPD + bony repair
How are true combined EPLs Tx’d
As 1ry endo, 2ry perio
Consider root amputation, hemisection or separation to save some tooth tissue
Tx iatrogenic EPL
Perforations: seal ASAP
Prognosis dependent on size, location, T of Dx + Tx and sealing ability of material
