s10 - Periodontal considerations Flashcards
(132 cards)
1
Q
What is the primary goal of integrating periodontal health with fixed prosthodontics?
A
To ensure restorative designs maintain periodontal health and prevent inflammation.
2
Q
How does periodontal inflammation affect prosthetic esthetics?
A
It causes soft tissue changes (color, texture) and disrupts prosthesis harmony.
3
Q
Why are defective restorations harmful to the periodontium?
A
They increase plaque retention and may violate biologic width.
4
Q
What are the components of the biologic width?
A
Connective tissue (1.0 mm) + junctional epithelium (1.0 mm) = 2.0 mm total.
5
Q
Where is the CEJ located, and why is it clinically significant?
A
Cementoenamel junction; a landmark for margin placement and biologic width preservation.
6
Q
What is the normal width of a healthy periodontal ligament?
A
0.25 ± 0.1 mm.
7
Q
Name the three parts of the gingival attachment unit.
A
Free gingiva, attached gingiva, interdental papillae.
8
Q
What is the ideal gingival sulcus depth?
A
1–2 mm.
9
Q
What are the two classifications of gingival biotype?
A
Thin (15% prevalence) and thick (85% prevalence).
10
Q
Why is thin gingival biotype higher risk for recession?
A
Less tissue resilience to trauma/surgery; more prone to margin exposure.
11
Q
What prosthetic material is preferred for thin biotype cases?
A
All-ceramic crowns (avoid metal margins to prevent visibility).
12
Q
How does thick biotype respond to crown preparation?
A
Better resistance to recession and inflammation.
13
Q
Define biologic width.
A
The combined height of connective tissue + junctional epithelium (2.0 mm).
14
Q
What happens if a restoration violates biologic width?
A
Chronic inflammation, bone loss, and gingival recession.
15
Q
Name two crown lengthening procedures to correct biologic width violation.
A
Gingivectomy, apically repositioned flap with osseous surgery.
16
Q
When is forced tooth eruption used for biologic width?
A
For subgingival caries/defects to expose sound tooth structure.
17
Q
What is the minimum space required between restoration margin and alveolar crest?
A
3.0 mm (2.0 mm biologic width + 1.0 mm sulcus).
18
Q
How does laser-assisted crown lengthening work?
A
Recontours gingiva/bone during crown prep to establish biologic width.
19
Q
What factors influence occlusal force impact on periodontium?
A
Severity, direction, duration, frequency.
20
Q
Differentiate primary vs. secondary occlusal trauma.
A
Primary: excessive force on healthy periodontium; Secondary: normal force on diseased periodontium.
21
Q
How does occlusal trauma worsen periodontal disease?
A
Accelerates bone loss and attachment loss.
22
Q
What is the center of rotation in occlusal trauma?
A
The fulcrum point around which a tooth tilts under excessive force.
23
Q
When is a double-cord gingival retraction technique preferred?
A
For deep subgingival margins or thick gingiva.
24
Q
Why must excess cement be removed after crown cementation?
A
To prevent gingival inflammation and periodontal destruction.
25
What are the advantages of supragingival crown margins?
Easier hygiene, less gingival irritation, and better marginal adaptation.
26
List 3 indications for subgingival margin placement.
1) Caries/restorations extending subgingivally, 2) Esthetic demands, 3) Need for retention/resistance.
27
How should margin placement relate to sulcus depth?
Place margin at half the sulcus depth (e.g., 0.5 mm below crest for 1.5 mm sulcus).
28
What causes "stepped" marginal junctions, and why are they problematic?
Poor preparation/adaptation; they trap plaque and impair sealing.
29
Why is overcontouring crowns harmful to periodontium?
Promotes plaque accumulation and hinders cleaning.
30
What is the ideal proximal contact design to prevent food impaction?
Flat/slightly concave axial surface cervical to contact; wider lingual embrasure.
31
How does excessively broad proximal contact affect gingiva?
Creates narrow embrasures → traps debris → inflammation.
32
What is the emergence profile, and why is it important?
Contour from gingival sulcus to height of contour; facilitates hygiene access.
33
What axial contour feature protects interdental papilla?
Straight profile in gingival third (avoids tissue impingement).
34
What is the key requirement for pontic-gingival contact?
Passive (pressure-free) to prevent ulceration.
35
Which pontic design is ideal for anterior esthetics?
Modified ridge lap (convex lingual, concave buccal).
36
Why avoid saddle pontics in posterior areas?
Concave design traps plaque; hygienic pontics (sanitary/conical) preferred.
37
What is the advantage of an ovate pontic?
Mimics natural gingival architecture; stabilizes tissue.
38
How does the E-pontic design enhance hygiene?
Flat tissue surface allows floss contact; promotes gingival migration.
39
When is a sanitary pontic indicated?
Posterior areas where hygiene > esthetics.
40
What material is most biocompatible for pontics?
Glazed porcelain (smooth, plaque-resistant).
41
Why is polished gold a good pontic material?
Corrosion-resistant, less plaque retention than unpolished metals.
42
What are the risks of resin pontic materials?
Porous surface → plaque accumulation; less durable.
43
Why reduce occlusal width in pontics by 1/5–1/3?
Decreases force on abutments.
44
When is maintaining normal occlusal width justified?
For proprioceptive feedback and stable occlusion.
45
How does collapsed ridge affect pontic design?
Requires narrower buccolingual dimension for hygiene access.
46
What is the self-cleaning mechanism of proper pontic design?
Deflects food from proximal areas.
47
How does occlusal force regulation relate to pontic width?
Proprioception adjusts bite force regardless of pontic size.
48
What does a BPE score of 3 indicate?
Periodontal pocket depth of 3.5–5.5mm with bone loss.
49
How is Grade 2 tooth mobility defined?
Horizontal mobility >1mm but no vertical displacement.
50
What prosthetic complication is gum recession most likely to cause?
Cervical sensitivity and esthetic challenges in margin placement.
51
Which furcation grade allows a probe to pass completely through?
Grade III (through-and-through).
52
What is the primary goal of initial periodontal therapy before prosthetics?
Control inflammation (plaque/calculus removal, OH instruction).
53
When is splinting contraindicated for mobile teeth?
Grade 3 mobility (severe horizontal + vertical movement).
54
What is the minimum acceptable crown-root ratio for an abutment?
1:1 under normal conditions.
55
Why is a chamfer finish line preferred over a shoulder for weakened teeth?
Less invasive, preserves tooth structure, reduces stress concentration.
56
What are the two main types of pre-prosthetic periodontal surgery?
Soft tissue procedures (e.g., grafting) and hard tissue procedures (e.g., crown lengthening).
57
How does a non-rigid connector in a FPD benefit periodontally compromised abutments?
Reduces stress on individual abutments by allowing slight movement.
58
What is the key advantage of telescopic crowns in periodontal prosthesis?
Distributes occlusal forces and allows retrievability.
59
Why should cantilever bridges be avoided in periodontal patients?
Leverage effects increase abutment stress and failure risk.
60
What is the purpose of axial fluting in tooth prep for weakened teeth?
Preserves dentin and mimics natural root anatomy.
61
Which BPE scores warrant specialist referral?
BPE 4 or * (furcation involvement).
62
What are the 3 components of plaque control in initial therapy?
Patient education, mechanical removal, chemical adjuncts (e.g., CHX).
63
How does Grade II furcation involvement differ from Grade I?
Grade II: Partial bone loss (>1/3 tooth width); Grade I: Early (<1/3).
64
What is the primary risk of overhanging restorations?
Plaque retention → periodontal inflammation.
65
When is root amputation indicated?
Class II/III furcation in multi-rooted teeth with one salvageable root.
66
What is the 5-year rule for tooth prognosis?
If survival <5 years, extract and consider implants.
67
Why is monolithic zirconia recommended for periodontally compromised teeth?
High strength and biocompatibility with minimal prep.
68
What is the BOPT technique?
Biologically Oriented Prep Technique – no horizontal finish line, encourages gingival adaptation.
69
How does splinting improve mobility prognosis?
Distributes forces across multiple teeth.
70
What is the #1 factor in abutment selection for FPDs?
Periodontal health (no pockets, stable bone).
71
What radiographic tool is best for assessing furcation involvement?
CBCT (3D bone loss visualization).
72
What are the 3 key steps in managing gum recession prosthetically?
Margin placement subgingivally, smooth emergence profile, avoid overcontouring.
73
When would you choose a knife-edge finish line over chamfer?
For severely elongated teeth or minimally invasive preps to preserve tooth structure.
74
What are the contraindications for crown lengthening?
Inadequate root length, risk of furcation exposure, or poor crown-root ratio post-op.
75
How does pink porcelain address gingival recession prosthetically?
Mimics gingival color to mask recession in high smile line cases (esthetic compromise).
76
What is the purpose of provisional splints in periodontal therapy?
Stabilize mobile teeth during healing and test occlusal function before final restoration.
77
Why is root resection preferred over extraction in furcation-involved molars?
Preserves alveolar bone and avoids adjacent tooth disruption.
78
What are the 3 key requirements for successful telescopic crowns?
Parallel preparation, adequate retention, and passive fit.
79
How does a featheredge margin design benefit periodontally compromised teeth?
Minimal tooth reduction and better gingival margin adaptation.
80
What is the biggest risk of overcontouring FPD pontics?
Plaque accumulation and gingival inflammation.
81
When would you recommend a removable vs. fixed splint?
Removable: Temporary stabilization; Fixed: Long-term stability for Grade I-II mobility.
82
What are the 2 main advantages of zirconia in periodontal prosthetics?
Biocompatibility and high fracture resistance with conservative preps.
83
How do you manage a tooth with 50% bone loss but no mobility?
Splint to adjacent teeth and optimize occlusion to reduce forces.
84
What is the primary goal of gingivage in BOPT?
Encourage gingival repositioning around feather-edge margins.
85
Why are non-rigid connectors contraindicated in cantilever FPDs?
Exacerbates leverage forces on abutments.
86
What surgical technique would you use for a Class III furcation defect?
Root amputation (if salvageable) or extraction + implant.
87
How does occlusal adjustment protect periodontally compromised abutments?
Reduces lateral forces that worsen mobility.
88
What are the 3 phases of treatment for advanced periodontitis patients?
1. Anti-infective → 2. Surgical → 3. Prosthetic.
89
Why is monolithic zirconia contraindicated for anterior crowns?
Limited translucency (esthetic compromise).
90
What is the key difference between hemisection and root amputation?
Hemisection: Splits tooth into two; Amputation: Removes one root.
91
How does a well-designed emergence profile protect periodontium?
Prevents food impaction and allows cleansability.
92
What are the 2 worst prosthetic mistakes in periodontal patients?
Overcontouring and subgingival overhangs.
93
When would you use a removable partial denture instead of FPD?
Poor abutment prognosis or need for future modifications.
94
What is the #1 predictor of long-term FPD success in periodontal patients?
Stable periodontal health post-therapy.
95
How do you assess "adequate" crown-root ratio for abutments?
1:1 is minimum, but 2:3 is ideal for compromised teeth.
96
What is the role of CBCT in periodontal prosthetics?
Evaluates 3D bone volume for implant planning or root resection.
97
What are the 3 keys to managing worn dentitions with periodontal disease?
1. Crown lengthening → 2. Occlusal stabilization → 3. Full-coverage restorations.
98
99
What is the primary concern when preparing a tooth with inadequate keratinized gingiva?
Preserving biological width and avoiding gingival recession.
100
Why is a shoulder finish line risky near the CEJ in periodontally weakened teeth?
It requires excessive axial reduction, weakening the tooth and risking pulp exposure.
101
How does a chamfer margin compare to a shoulder margin in terms of invasiveness?
Chamfer is less invasive and conserves more tooth structure.
102
What happens if biological width is violated during tooth preparation?
Gingival inflammation, recession, or bone loss may occur.
103
When should a feather-edge margin be used instead of a shoulder?
For elongated teeth or minimal tooth structure to avoid excessive reduction.
104
What are the three main types of horizontal finish lines?
Shoulder, inclined shoulder (50°/135°), and chamfer.
105
Why is a feather-edge margin considered "vertical preparation"?
It lacks a distinct horizontal finish line, blending into the axial wall.
106
Which margin design is least suitable for PFM crowns on periodontally weakened teeth?
Shoulder (due to excessive tooth removal).
107
What is the key advantage of a knife-edge margin in zirconia crowns?
Minimal tooth reduction and better marginal adaptation.
108
How does a chamfer margin affect stress distribution compared to a shoulder?
Chamfer reduces stress concentration, lowering fracture risk.
109
When is an inclined shoulder (135°) preferred over a standard shoulder?
For better esthetics in deep subgingival margins.
110
What is the defining feature of BOPT?
Vertical preparation with no horizontal finish line.
111
What materials are recommended for BOPT crowns?
Monolithic zirconia or hybrid ceramics.
112
Why is rotary curettage performed in BOPT?
To remove epithelial lining and enhance gingival adaptation.
113
What is a key contraindication for BOPT?
Teeth with insufficient ferrule or severe gingival recession.
114
How does BOPT improve emergence profile in restorations?
Mimics natural tooth contour, reducing plaque retention.
115
Why should axial walls have vertical concavities in periodontally compromised teeth?
To follow root anatomy and avoid overcontouring.
116
What is the purpose of a wide metallic collar in PFM crowns for weakened teeth?
Covers exposed root but compromises esthetics.
117
Why is monolithic zirconia preferred over bilayered crowns in BOPT cases?
Better strength and no veneer chipping risk.
118
What is the main drawback of metal-ceramic crowns in gingival recession cases?
Grayish margin visibility (poor esthetics).
119
How does fluting axial walls benefit periodontal health?
Prevents horizontal bulges that trap plaque.
120
When is a knife-edge margin contraindicated?
In thin gingival biotypes or high caries risk.
121
What is the primary goal of crown-lengthening surgery?
Expose sound tooth structure while maintaining biological width.
122
Which non-surgical method improves black triangles between teeth?
Composite bonding or ceramic staining (optical illusion).
123
What is the role of orthodontics in papilla reconstruction?
Coronal repositioning of gingiva to close embrasures.
124
When is a coronally advanced flap used?
For root coverage in gingival recession cases.
125
What is the difference between root amputation and hemisection?
Amputation removes one root; hemisection splits the tooth into two halves.
126
When is bicuspidization indicated?
For mandibular molars with Class II/III furcation involvement.
127
What is the key prerequisite for root resection?
Adequate bone support on remaining roots.
128
Why is endodontic treatment mandatory before hemisection?
To ensure pulp health in retained roots.
129
What prosthetic option follows root resection?
Separate crowns or a fixed bridge.
130
According to the 10-year rule, when should a tooth be extracted?
If its prognosis is <5 years.
131
What factors favor implant placement over periodontal therapy?
Advanced bone loss, poor crown-to-root ratio.
132
When should a tooth with 5–10 year prognosis be retained?
If adjacent to an edentulous site (to avoid implant complications).
