Periodontal Surgery/Regenerative Dentistry Flashcards
(167 cards)
1
Q
What is Step 0 in the BSP guidelines?
A
Pre-requisite to therapy: Educate, classification, diagnosis, risk assess, care plan.
2
Q
What is Step 1 in the BSP guidelines?
A
Risk factor control, OHI, adjuncts for GI, PMPR supra-gingival scaling.
3
Q
What is the overall aim in step 1?
A
To provide preventative and health promotion tools to the patient.
4
Q
What treatment/advice/instructions are you giving to a patient in step 1?
A
- Implementation of patient motivation strategies
- Implementation of behaviour changes
- Control of local risk factors
- Control of systemic risk factors
- PMPR supragingival plaque and calculus
5
Q
What are you evaluating at the end of step 1?
A
If the patient is engaging
6
Q
What would you see in an engaging patient clinically?
A
Improvement in OH= >50%
Plaque levels <20%
Bleeding <30%
Meeting targets in self care plan
7
Q
What would you see in an non-engaging patient clinically?
A
Insufficient improvement in OH <50%
Plaque levels >20%
Bleeding >30%
States preference to palliative approach
8
Q
Why are microsurgical instruments such as a microsurgical scalpel blades and magnification is advised, what advantages do they have?
A
- Improves soft tissue handling
- Less invasive treatment (minimise trauma)
- Greater stability of site post surgery to improve healing.
9
Q
If a patient is shown to be engaging then you can progress onto step 2. What is involved in step 2 in the BSP guidelines?
A
- Subgingival instrumentation reduced PPD, gingival inflammation and diseased sites. Can be done with ultrasonic or hand instruments. Can be done per quadrant or full mouth protocol.
10
Q
What are the overall aims in Step 2 ?
A
- NSPT is particularly successful if there is good patient compliance/buy-in and appropriate professional management.
- The aim is to control dysbiosis: controlling microbial load/composition and reducing inflammatory infiltrate.
- NSPT improves soft tissue quality which helps handling during surgery.
11
Q
What are you evaluating at the end of step 2?
A
Whether the patient is stable or non-stable.
12
Q
What would you see clinically if the patient is stable?
A
No periodontal pocket greater than or equal to 4mm with BOP
No remaining deep sites greater than or equal to 5mm.
13
Q
What would you see clinical if the patient is unstable?
A
Deep sites remain that are greater than or equal to 5mm
BOP in pockets greater than 3mm
14
Q
You would progress onto step 3 if the patient has had failure of step 2 and is still “unstable”. What is involved in step 3?
A
Non responder sites: Re-RSD or periodontal surgery
15
Q
Would you carry out perio surgery in an non-engaged patient?
A
No, will fail. Instead focus on OH and behaviour changing
16
Q
What is periodontal surgery?
A
A collection of surgical interventions involving the supporting tissues of teeth.
Can be: regenerative, resective, reparative
17
Q
What are 3 clinical indications where periodontal surgery is recommended?
A
- PPD greater than or equal to 6mm
- Infra bony defect greater than 3mm
- Furcation involvement class 2
18
Q
Who should periodontal surgery be carried out by?
A
Dentists with additional specific training.
19
Q
When is periodontal surgery not indicated?
A
Should not be done when self-performed OH is insufficient. Plaque score <20-25% consistently associated with better surgical outcomes.
20
Q
What is the overall aims of periodontal surgery?
A
Pocket reduction
Improvement of gingival contour
Improvement of access for oral hygiene measures
Access to inaccessible, non-responding sites for diagnosis and management
Regain lost clinical attachment
21
Q
Name 5 general considerations for periodontal surgery.
A
- Patient wishes
- Non-surgical periodontal care therapy not successful at this site
- Oral hygiene compliance
- Long term prognosis of tooth and strategic value
- Operator experience and resources
22
Q
When considering systemic considerations for periodontal surgery, what are some absolute contra-indications?
A
- Bleeding conditions (INR >3-3.5, low platelets)
- Recent MI or stroke (< 6 months)
- Recent valvuluar prosthesis placement or transplant (<6-12months)
- Significant immunosuppression
- Active cancer therapy
- IV bisphosphonate treatment
23
Q
When considering systemic considerations for periodontal surgery, what are some relative contra-indications?
A
- Patient wound healing potential (genetic)
- Social history e.g smoking
24
Q
What is the effect of smoking on periodontal surgery.
A
-Smoking impairs wound healing : less attachement gain and PD reduction after surgery in smokers
May be a contra-indication to perio surgery - cessation beforehand is important
25
When considering local/dental considerations for periodontal surgery, what are some soft tissue considerations?
- Phenotype
- Interdental papilla
- Volume of keratinized, attached gingival tissue
- Pocket depth
26
When considering local/dental considerations for periodontal surgery, what are some hard tissue considerations?
- Defect angulation (less than 25 degrees better than greater than 37 degrees).
- Number of bony walls of infrabony defect.
- Defect of depth
27
What are some other local/dental considerations for periodontal surgery apart from soft/hard tissues?
- Local anatomical structures (access for surgery)
- Oral hygiene
28
What would you do if the patient declines periodontal surgery?
Ensures patient understands significance of incompletely managed periodontitis on remaining teeth.
Teeth with advanced CAL and residual deep pockets can be maintained for many years with SPC
29
What is the case selection criteria at DDH for periodontal surgery.
Evidence of:
- NSPT and RSD under LA carried out to maximum potential
- Minimum supra/sub gingival calculus deposits present
- Compliance with smoking cessation
- Good plaque control demonstrated, plaque free score >80%
- Presence of PPD >6mm and BOP and suppuration
- No/minimal mobility, or able to splint grade 1/2 teeth
- Pre-operative radiograph showing clear bony morphology
30
What do you need to consent the patient of for periodontal surgery?
- Pain
- Bleeding
- Swelling
- Bruising
- Infection
- Recession
- Scarring
- Transient mobility of teeth
- Dentinal sensitivity
- Failure of procedure
- Use of biomaterials
31
What pre-operative advice would you give patients before periodontal surgery?
Wear loose clothing, especially layers? wit
Unless having GA or sedation, have a good breakfast/lunch
Take all regular medication unless otherwise advised
If concerned about getting home, have someone with you
Long procedure: put enough money on parking meter
Can change mind about going ahead if they wish: even if they have signed consent forms.
32
What post-operative instructions would you give a patient after periodontal surgery?
Take regular analgesia: paracetamol and ibuprofen effective
Use of ice packs for first 12 hours to reduce swelling: wrap in teatowel
Avoid brushing surgical site until sutures are removed: use chlorohexidine mouthwash twice daily until this.
Suture removal at 7-14 days : longer in grafting surgery to remove stability
No probing or instrumentation of site for 3 months MINIMUM: 9-12 months if biomaterials used.
33
What should you not do for flap design?
- Don't cut on max bulbosity of root (cause difficult closing flap)
- Don't cut diagonal relieving incisions
- Flap should always be broader width than height
- Dont cut vertically through papilla
34
What is split/partial thickness flaps?
Leaves the periosteum and part of the connective tissue in tact.
35
What is full thickness flap?
Incorporates the epithelium, connective tissue and periosteum.
36
What type of sutures were traditionally used for periodontal surgery? Why arent they used anymore?
Traditionally used black silk/multi-filament materials. This has caused bacterial colonisation and wickening.
37
What type of sutures is now used typically for periodontal surgery and why?
- Now use synthetic mono-filament suture
- Resorbable or non-resorbable
- non-wickening
- Low bacterial colonisation
- Can be difficult to tie as "springy"
38
What instructions would you give to a patient after placing sutures?
- No brushing in the region
- Use chlorohexidine mouthwash to reduce plaque formation
39
Why are periodontal dressings used commonly?
- Cover raw wound edges in gingivectomy
- Control healing after gingivectomy
- Stabilise free gingival graft
40
What are the downsides to using periodontal dressings instead of placing sutures?
- Patients don't like it much (function and aesthetics)
- Difficult handling and placement
- Concerns can get bacterial growth underneath as this doesnt create a seal
41
What are the 3 different types of periodontal surgery?
- Resective
- Repair/reattachment
- Regenerative
42
What are 5 different types of resective surgery?
- Gingivectomy
- Root resection
- Apically repositioned flaps
- Osseous reduction
- Distal wedge incision
43
What is an aesthetic disadvantage to carrying out resective surgery?
Can cause gingival resection
44
What are 2 different types of repair/reattachment
- Open flap debridement
- Modified Widman Flap
45
What are 3 different types of regenerative surgery?
- Guided Tissue Regeneration
- Grafts
- Emdogain
46
Give a description for resective surgery.
Pocket elimination procedures which establish a morphologically normal attachment but with apical displacement of the dento-gingival complex.
47
Give a description of repair-reattachment surgery
Pocket reduction surgery, but without replication of the normal attachment. In other words, healing is by formation of a long junctional epithelium. Normally managed with partially reflected flap (crevicular incision without relieving incisions).
48
What type of flap is commonly used for repair-reattachment surgery?
Partially reflected flaps
49
Name 2 types of partially reflected flaps and which one is used most commonly?
Most common: Open Flap Debridement
Modified Widman Flap
50
What are the surgical aims when carrying out repair-attachment surgery with partially reflected flaps?
- Access for RSD under direct vision
- Assessment of root surface (grooves,fractures, enamel pearls, iatrogenic damage)
51
Describe the different surgical stages of open flap debridement.
1. Patient consent and adequate local anaesthesia
2. 1min chlorohexidine mouth rinse and pre-operative preparation
3. Incision in gingival sulcus to allow access to pathological pocket
4. Raise full thickness flap, limited to 1mm below alveolar crest
5. Removal of granulation tissue from site
6. Scaling of tooth surfaces under direct vision
7. Closure with sutures
52
What is a Modified Widman Flap?
Involves resection of soft tissue collar from gingival margin. Incision is 0.5-1mm from gingival margin. Aim is to remove inflammation tissue to promote healing
53
What are 5 indications for partially reflected flaps.
- Excellent maintenance
- Site > 6mm or equal to with BOP or suppuration.
- Horizontal bone loss pattern
- Vertical defect < or equal to 3mm
- Isolated periodontal pockets remain
54
What are 4 contra-indications for partially reflected flaps.
- Aesthetic region
- Need for graft/membrane
- Complex furcation/bone defects
- Lack of/limited attached gingivae (MWF)
55
What are 3 advantages of partially reflected flaps?
- Healing by primary intention
- Minimal crestal bone resorption
- Effective in pockets 6-7mm
56
What are 4 disadvantages of partially reflected flaps?
- Can be unpredictable (dependent on healing potential)
- No new attachment (healing by long junctional epithelium)
- Risk of recession
- Interdental craters
57
Give a description of regenerative surgery.
Recreation of the complete attachment apparatus of bone/cementum/ functionally orientated periodontal ligament against previously exposed root surface.
58
What differences post-operatively are you likely to see when comparing regenerative to repair surgery.
Repair: Long junctional epithelium, crestal remodelling.
Regeneration: New cementum, new PDL, new bone.
59
Name the surgical aims to regeneration surgery.
1. Regenerate Defect: gain clinical attachment, minimise soft tissue recession, increase bone volume
2. Remove factors associated with disease progression: residual deep sites, infrabony defects, furcation involvement, BOP
3. Enhance access for plaque control and maintenance
60
Name 4 things required for regeneration to occur.
1. PDL cells
2. Wound stability
3. Space provision
4. Primary intention healing
61
What would be the outcome of healing of epithelial cells?
Healing at long junctional epithelium
62
What would be the outcome for healing of gingival connective tissue cells?
CT attachment or root resorption
63
What would be the outcome for healing of bone cells?
Root resorption or ankylosis
64
What would be the outcome of healing of mesenchymal cells?
Regeneration
65
What would be the case selection/criteria for regenerative surgery?
- Infrabony defect associated with a periodontal pocket of greater than or equal to 6mm
- Depth of vertical defect >3mm
- Narrow defect (less than 25 degrees ideally)
- Higher number of bony walls
- Class 2 furcation in mandibular molars
- Single class 2 furcation in maxillary molars
66
Name different regenerative techniques/materials you can use in this surgical procedure.
- Guided tissue regeneration (GTR)
- Bone graft materials
- Enamel matrix proteins (EMD)
- Combinations eg GTR and bone or EMD and bone
67
Give a description of Guided Tissue Regeneration (GTR)
Use of mechanical barrier (membrane) to selectively enhance the establishment of PDL and peri-vascular cells in osseous defect to initiate periodontal regeneration. Used for teeth with periodontal bone loss and infrabony defects.
68
What are 3 surgical aims for Guided Tissue Regeneration (GTR)
1. Stop rapid downgrowth of epithelial cells
2. Create space for pluripotent cells from PDL to access root surface
3. Improve local anatomy, function and prognosis of teeth
69
What is the function of a membrane in regenerative surgery?
Act as a barrier to prevent cells apart from PDL migrating into site: provide "space" for regeneration, promotes PDL cells for regeneration.
70
There are multiple types of membrane available to use in surgery, what is the downside of using resorbable membranes?
Resorbable less predictable duration/stability
71
What is the downside of using non-resorbable membranes?
Non-resorbable require second surgery to remove.
72
What is the surgical risk of using membranes?
Membranes can be exposed, leading to complications.
73
What are the different sources you can get bone graft/substitutes from?
Autograft: from a donor site or same person
Allograft: from a different person but human bone
Xenograft: from an animal source
Alloplast: synthetic material
74
What is advantage of using bone graft when suturing?
Bone graft supports flap, providing "space" and "stability" for regeneration.
75
What is the advantages of using autogenous bone?
Has osteogenic and osteoinductive properties. Other grafts are osteoconductive only.
76
What is Emdogain? (Enamel matrix proteins)
Emdogain (EMD) mimics the development of tooth supporting apparatus during tooth formation. 90% is amelogenins (cocktail of proteins). Contains propylene glycol alginate (PGA).
77
What are advantages of using Emdogain?
Accelerates wound healing
Direct effects on cellular behaviour to promote regeneration (PDL and alveolar bone formation are dependent on new cementum formation).
78
What is the effect of EMD on epithelial cells?
Decreased cell proliferation and migration
79
What is the effect of EMD on gingival fibroblasts?
Reduced cell migration
80
What is the effect of EMD on bone?
Increased cell proliferation and migration, support of bone formation but not osteoinductive.
81
What is the effect of EMD on PDL fibroblasts?
Increased cell proliferation, migration and attachment.
82
What is the effect of EMD on cementoblasts?
Increased in vivo mineralisation
83
Describe the different surgical stages of regeneration surgery.
1. Patient consent and adequate local anaesthesia
2. 1min chlorohexidine mouth rinse and pre-operative preparation
3. Incision in gingival sulcus to allow access to pathological pocket
4. Raise full thickness flap, limited to 1mm below the alveolar crest
5. Removal of granulation tissue from site
6. Scaling of tooth surfaces under direct vision
7. Place membrane/graft/EMD or combination into defect
8. Closure with sutures
84
What is the expected outcome with using EMD and GTR?
No additional benefit compared with each alone
85
What is the expected outcome with using EMD and graft?
Improved outcomes with EMD and xenograft/autogenous bone. No improvement with alloplastic materials.
86
What is the expected outcome with using graft and GTR?
Best combination for non-contained defects.
87
What is the expected outcome with using EMD, GTR and graft?
No additional benefit compared to two combined.
88
Name 4 advantages for carrying out regenerative surgery.
1. Successful in the treatment of deep sites of 6mm or greater
2. Healing by primary intention
3. Improvement in volume of supporting tissues of tooth
4. Less recession for patient
89
Name 3 disadvantages for carrying out regenerative surgery.
1. Technically challenging to get good outcome
2. Can be unacceptable for some patients depending on materials used - need good consent
3. Expensive materials
90
What is gingival overgrowth and what is the causes?
Abnormal overgrowth of gingival tissues. Can be localised or generalised. Multiple causes: inflammatory, drug-induced, related to systemic conditions
91
What is a gingivectomy?
- Management of gingival overgrowth by resection/recontouring of gingivae
- Radical procedure (rarely used in the treatment of periodontitis now)
- Leaves raw round (healing by secondary intention 0.5mm epithelialisation per day, periodontal dressing to cover for 7-14 days).
92
What are 4 indications for a gingivectomy?
1. Gingival enlargement/ overgrowth persists despite non-surgical care
2. Supra bony periodontal pocketing
3. Excellent at home care
4. Wide zone of attached gingivae
93
Name 4 contra-indications for a gingivectomy?
1. Narrow attached gingivae
2. Planned osseous recontouring
3. Infra-bony periodontal pockets
4. Medical contra-indications (esp bleeding disorders)
94
Name 3 advantages for a gingivectomy.
1. Simple
2. Good vision
3. Can achieve ideal tissue morphology
95
Name 5 disadvantages for a gingivectomy.
1. Limited indications
2. Heal by secondary intention (painful)
3. Risk bone exposure
4. Wastes attached gingivae
5. Excessive recession in PD disease (aesthetics, sensitivity, root caries, abrasion).
96
What is surgical crown lengthening?
A surgical procedure which apically repositions the soft tissue and alveolar bone to expose more tooth structure, and increase the length of the clinical crown. Normally a resective procedure depending on amount of attached gingiva available
97
What is the overall aim for surgical crown lengthening?
Surgically maintain biological width whilst apically repositioning the gingival level.
98
Name 7 indications for surgical crown lengthening.
1. Toothwear
2. Poor gingival aesthetics
3. Restoration of subgingival lesions
4. Replacement of crowns with deep margins
5. Management of coronal third fractures
6. Management of infringement of biological width
7. Develop ferrule for pulpless teeth restored with posts
99
Name 6 contra-indications for surgical crown lengthening.
1. Poor plaque control
2. Poor compliance
3. Non-functional teeth or teeth with poor strategic value
4. Periodontal destruction
5. Endodontic compromise
6. Medical history considerations
100
Name 5 complications of surgical crown lengthening.
1. Poor aesthetics due to black triangles
2. Transient mobility of teeth
3. Root sensitivity
4. Rebound of marginal tissues
5. Root resorption
101
Name 7 different treatment options for furcation involved teeth?
1. Non- surgical periodontal therapy (grade 1)
2. Odontoplasty (grade 1 and 2)
3. Open flap debridement (grade 2)
4. Tunnelling procedure (grade 3)
5. Root resection or separation
6. Regenerative procedure (grade 2)
7. Extraction
102
What is an odontoplasty?
Reduces plaque accumulation by reshaping tooth surface with a bur. Can aid in treatment of grade 1 and shallow grade 2 lesions. Surgical procedure involving raising a flap buccal and lingual to the site. Can result in hypersensitivity and caries.
103
Can open flap debridement be effective in shallow defects to eliminate pockets?
Yes.
104
What is tunnel preparation?
Used in mandibular molars with deep degree 2 and 3 lesions. Aims to improve ability for oral hygiene measures. Can only be done with wide furcation entrance (most likely mandibular molars).
105
Describe the procedure for tunnel preparation.
- Buccal and lingual flap raised
- Granulation tissues removed and RSD.
- Furcation widened by enough bone removal to allow access for cleaning between roots post-operatively.
- Flaps apically re-positioned
106
State 3 risks you are increased of with tunnel preparation.
1. Root caries
2. Loss of vitality
3. Sensitivity
107
What is root resection?
Removal of one root of a multi-rooted tooth where there is uneven bone loss.
108
Name 4 indications of root resection.
1. Class 2/3 furcation involvement.
2. Severe bone loss on 1 or more roots
3. Root fracture/perforation/deep caries.
4. Failed endodontic treatment or inoperable canals.
109
What are 4 contra-indications of root resection.
1. Inaquate bone support of remaining roots
2. Unfavourable anatomy (fused roots, long root trunk).
3. Significant discrepancies in bone height
4. Remaining roots not restorable
110
What does the term "hemi-section" mean in mandibular molars?
Includes removal of a portion of the crown.
111
What must be carried out on the tooth before root resection?
RCT
112
In general, what roots do you get better success with on upper molars?
MB or DB
113
In general, what roots do you get better success with on mandibular molars?
Mesial roots of lower molars.
114
What is root separation?
Carried out infrequently. Indicated in extensive furcation involvement where bone loss around both roots is similar.
Root treated tooth --> surgical division --> restoration as 2 teeth
115
What would the treatment be for class 1 furcation involvement tooth ?
NSPT
116
What would be the treatment for class 2 furcation involvement of tooth?
If interproximal bone level below furcation entrance --> resective therapy e.g tunnel, apically repositioned flap, root amputation or hemisection.
If interproximal bone level above furcation entrance--> regeneration surgery: e.g Graft + GTR
117
What would be the treatment for class 3 furcation involvement of tooth?
Resective therapy: e.g apically repositioned flap, tunnel, root amputation or hemisection
Extraction
118
What is gingival recession?
Location at the marginal tissue apical to the cemento-enamel junction with exposure of the root surface
A hard tissue dehiscence must be present
119
Name 4 possible aetiological factors of recession.
1. Traumatic (toothbrushing, partial dentures, lip/tongue piercing, self-inflicted)
2. Traumatic overbite
3. Periodontal disease
4. Poor restorative margins (plaque retention, encroach of biological width).
120
Name factors that make a patient at increased risk of recession.
Thin tissue phenotype
High muscle attachment/frenal pull
Alveolar dehiscence
Teeth outside alveolar bone after orthodontic treatment (proclination of incisors, arch expansion)
Lack of keratinized tissues
121
Name 4 non-surgical management options of recession
1. Monitoring and prevention
2. Composite restorations
3. Gingival prosthesis
4. Orthodontics
122
Name 5 surgical management options of recession
1. Frenectomy
2. Pedicle flaps
3. Free gingival flaps
4. Subepithelial connective tissue graft
5. Coronally advanced flap + GTR
123
Name 5 indications of surgical management of recession.
1. Prevention of continued recession
2. Improve ability to perform OH measures
3. Aesthetic concern
4. Sensitivity
5. Root caries
124
Name 7 contra-indications of surgical management of recession.
1. Poorly controlled diabetes
2. Bleeding disorders
3. Smoking
4. Poor OH
5. Active periodontal disease
6. Previous failed procedures
7. Self-inflicted injuries
125
What is a frenectomy and what is the overall surgical aims?
Removal of local muscle insertion
Aims: Stabilise tissue, improve access for oral hygiene measure
126
Name 3 indications for a frenectomy?
1. Unstable local tissue: movement, blanching on retention
2. Blocking access for OH measures
3. Non-recession indications: midline diastema in ortho, shallow vestibule for prosthesis.
127
Name 2 contra-indications for frenectomy?
1. Medical/bleeding disorders
2. Scar formation will make further more challenging - consider internal frenectomy.
128
Why do we graft?
Connective tissue determines overlying epithelial characteristics.
Rotated split thickness flaps retain some underlying CT
Grafted CT from palate promotes robust, attached, keratinised tissue
Different levels and position of CT graft have different effects.
129
What is the overall surgical aims of frenectomy ?
- Improve/create band of keratinised attached gingivae
- Avoid scarring
- Optimal tissue blend/colour match
- Improve access for OH
- 100% root coverage
130
What is a pedicle flap?
Moving adjacent attached gingivae to cover a region of recession using a split thickness flap
Can be laterally repositioned or double papilla
131
Name 3 indications for a pedicle flap?
1. Narrow defect on single tooth
2. Adjacent teeth with thick phenotype or edentulous area
3. Deep vestibule
132
Name 5 contra-indications for a pedicle flap?
- Deep periodontal pocketing
- Loss of interdental tissue
- Large root prominences
- Lack of relevant local anatomy
- Deep root abrasions
133
Name 3 advantages of a pedicle flap
1. One site surgery
2. Good vascularity to pedicle flap
3. Root coverage possible
134
Name 5 disadvantages of a pedicle flap
1. Limited by amount of adjacent keratinised, attached gingivae
2. Risk of recession at donor site
3. Limited to a single tooth
4. Not as likely to regain root coverage
135
What is a free gingival graft and what are the overall surgical aims?
Graft from the palate formed of epithelium and small amount of underlying connective tissue is placed into a region with localised recession
Aims: - To create a band of keratinised mucosa
- Remove frenal attachments
- Prepare site for second procedure to increase root coverage
136
Name 5 indications for gingival graft.
1. Discomfort during OH measures
2. Ongoing local inflammation
3. Lack of keratinised tissue in region of recession defect
4. Prevention of further recession
5. Insufficient local keratinised tissue for pedicle flap
137
Name 4 contra-indications for gingival graft.
1. Aesthetic region
2. Aim for complete root coverage
3. Donor site tissue poor
4. Medical contra-indications
138
Name 2 advantages of gingival grafts.
1. Relatively simple surgery
2. Increases vestibular depth
139
Name 3 disadvantages of gingival grafts.
1. Second surgical site
2. Palatal wounds heal by secondary intention
3. Unaesthetic: mismatch in colour, texture and thickness. Misalignment of muco-gingival junction.
140
What is a coronally advanced flap?
Surgical procedure where a split thickness flap is raised, released and then replaced in a more coronal position. Can be combined with a connective tissue graft from the palate, especially when: limited attached gingivae apical to recession, shallow sulcus, buccally placed root, interdental CAL.
141
What are 3 advantages of a coronally advanced flap?
- Possible for one site surgery
- Less technically demanding than tunnelling in thin phenotype, tissues mobilise more easily
- Can be combined with GTR , possible enhanced bone formation?
142
Name 3 disadvantages of a coronally advanced flap.
1. Often benefits from CT graft - second surgery site
2. If used with GTR, higher risk of infection
3. Vertical releasing incisions mean delayed healing.
143
What is modified coronally advanced tunnel with CT graft?
Split thickness raised without any releasing incisions and maintaining interdental papilla. Repositioned coronally with CT graft threaded through "tunnel" underneath gingivae
144
Name 3 advantages of a coronally advanced tunnel with CT graft?
1. Microsurgical technique (better healing and minimal scarring)
2. Excellent colour match
3. Better vascularisation of flap (excellent graft survival, excellent wound stability)
4. Best root coverage outcomes with CT graft.
145
Name 2 disadvantages of coronally advanced tunnel with CT graft.
1. Second operative site
2. Technically demanding (thin phenotype, graft harvesting).
146
What are the 4 stages of wound healing?
1. Haemostasis (blood clot)
2. Inflammatory
3. Proliferative (regenertion of cells to replace lost tissues or scar)
4. Remodelling
147
What is the difference between tissue repair and regeneration?
Tissue repair: laying down connective tissue (collagen) forming scars. Chronic inflammation causes fibrosis.
Regeneration: proliferation of cells to get full healing
148
What 4 different factors do you need for tissue repair?
Proliferation and migration of different cells
Laying down of extracellular matrix
Growth factors
Remodelling of collagen to form scar
149
Name some examples of cells that continuously divide in tissues.
- Stem cells
- Skin epithelium
- Salivary gland
- GI epithelium
150
Name some examples of cells that are stable (quiescent) in tissues.
- lymphocytes
- smooth muscle cells
- fibroblasts
- endothelial cells
151
What are some examples of cells that are permanent non-dividing in tissues.
- cardiac muscle cells
- skeletal muscle cells
152
Growth factor are specialised proteins that act as ligands - name different growth factors.
TGF-B
PDGF
FGF
EGF
153
What is TGF and what is its function in tissue repair?
transforming growth factor: most critical in tissue repair. Proliferate and stimulate fibroblasts to secret collagen. Repair fibrous connective tissue at the injury site.
154
What is PDGF and what is its function in tissue repair?
platelet derived growth factor: It calls neutrophils, macrophages, and fibroblasts to the injury site. Aids in wound contraction.
155
What is FGF and what is its function in tissue repair?
fibroblast growth factor: initiate the migration of epithelial cells , aids in wound contraction and stimulates angiogenesis (forming new blood vessels)
156
What is VEGF and what is its function in tissue repair?
Vascular endothelial growth factor: Angiogenesis
157
What is EGF and what is its function in tissue repair?
Epidermal growth factor: stimulate epithelial proliferation and enhances epithelial migration
158
What are the components of an extra-cellular matrix?
Interstitial matrix: collagen, elastin, fibronectin, proteoglycans, and hyaluronan.
Basement membrane: Nonfibrillar collagen, laminan, and proteoglycans.
159
What are 3 functions of the extra-cellular matrix (ECM)?
Structural: Firmness to bone (collagen and elastin)
Resilient: imparting resilience to soft tissues (hyaluronan and proteoglycans)
Adhesive: stores and presents growth factors, acts as scaffolds, facilitates cell growth (integrins, fibronectins, laminin).
160
Specifically what cells are used for differentiation and proliferation in regeneration?
Mesenchymal stem cells.
161
Where are the different sources of mesenchymal stem cells in teeth?
- dental pulp
- deciduous teeth
- periodontal ligament
- apical papilla
- dental follicle
- human periapical cysts
162
What different cells can mesenchymal stem cells from teeth differentiate into ?
- odontoblast
- osteoblast
- chondrocyte
- adipocyte
- myocyte
- endothelial
- neural
163
Describe the process for getting dental stem cells?
- Tooth is placed in transport medium immediately after exodontia or exfoliation
- Separation of dental tissue containing stem cells
- Explant or enzymatic and/or mechanical dissociation of dental tissue
- Apical papilla (explant)
- Dental stem cells in culture
164
What 3 factors are required to create engineered tissue?
1. Biomaterial scaffold
2. Cells
3. Growth factors/bioreactor
165
What are stem cells?
Stem cells are the bodys reserviour used to differentiate into cells that have been damaged to then replace them.
166
What is stem self- renewal?
Stem cell can make another stem cell
167
Name materials that are used as a scaffold in ECM in tissue engineering.
- Natural polymer: biocompatible, degradable, non-toxic but risk or transmitting pathogens, immunresponse
- Natural materials: proteins, polysaccharides, nucleic acids
- Collagen: mechanically weak, rapid degradation
-Synthetic scaffolds: PLA, PGA and PCL - nontoxic, biocompatible, immune response, acidic
- Co-polymers: PEG, PBT, PU; more useful.
