Prosthodontics Flashcards
What are the 5 general steps in fabricating an implant-supported prosthesis?
- Make impressions
- Select and prep abutment
- Fabricate crown or prosthesis
- Abutment delivery
- Prosthesis delivery
What are 2 levels at which impression can be taken?
- Implant level
2. Abutment level
Which type of impression is taken after an abutment has been delivered clinically?
Abutment level impression
Which impression is taken with copings that fit onto implants directly. No abutments are present?
Implant level impression
“implant level impression” means what must be placed before the impression is taken?
implant analog, device that mimics the implant in the stone model
“Abutment level impression” means what must be placed before the impression is taken?
Abutment analog
What is an abutment that requires abutment delivery prior to impression?
Internal friction
Which impression type requires subgingival placement of copings, and is more difficult?
Implant level impression
Which impression type requires impression copings?
Implant level impression
This impression means abutments can be chosen on a model in the lab
implant level impression (re: have a fixture in the cast to try things in on)
This impression means the abutment is chosen in the mouth chairside
Abutment level impression
Which impression might require abutment modification?
Abutment level (b/c implant level impression abutment can be modified in the lab)
Which impression has custom abutments available?
Implant level impression
Which impression has the interim and final crown fabricated in lab?
implant level impression
What are 2 types of impression copings for implant level impressions?
- Closed tray
2. Open tray
Which type of impression copings remain on the implant complex after the impression is removed and need to be placed into the impression manually?
Closed tray impression/transfer impression coping
What is an implant level impression type where impression copings are automatically retained in the impression after removal, usually requiring manipulation of a long screw that is not present in transfer copings?
Open tray/pickup impression
Which implant level impression type allows for more precise impressions?
Open tray/pickup impression
In what area of the mouth are implant level impressions using open tray/pickup impression copings contraindicated?
Posterior mouth due to decreased access. Closed tray/transfer copings indicated
What is an implant level impression type that is useful in multiple implant cases?
Open tray/pickup
What should be done after placing a transfer coping in an implant, but before taking the closed tray implant level impression?
Radiograph to ensure it is fully seated
Transfer copings are designed to fit into the impression in how many positions?
Only one
In what coping is the screw more prominent: transfer or pickup?
Pickup
Internal friction systems use what type of copings?
Resemble pickup copings, but clip onto implant
Which implant level impression is more precise, causes less distortion, but requires more interarch space, tray perforation, and can splint multiple copings?
Pickup copings/open tray implant level impression
When pouring cast of implant level impression, how far should the gingival moulage cover the implant analog?
~3mm cover of analog
Which abutment has set collar heights and taper and can be modified?
Prefabricated abutments
Which abutments are entirely fabricated in the lab, usually delivered with a machined metal connection and waxable sleeve?
Custom abutments/UCLA abutment
Which abutments are straight cylinders with no taper or margin level. Preparation is required to set height, angulation, taper, and margin
Prepable abutments
What is an implant component that lies between the implant and the crown?
Abutment
How is an abutment retained on an implant?
Abutment screw. Can be a source of movement.
What are 7 considerations for abutment selection?
- Case type
- Implant diameter
- Intra-arch space
- Interarch space
- Angulation
- Gingival margins
- Subgingival contours
Can abutments used for screw retained restorations normally be modified?
No
When restoring without abutments, what is the character of the restoration?
Screw retained
What impression is taken if restoring without an abutment?
Implant level impression
If the abutment preparation has occurred in the mouth, when is the abutment delivered?
At same time
When are abutments normally delivered?
Between implantation and final prosthesis delivery
Can abutments be delivered at time of final restoration?
Yes
When can the abutment be placed at the same time as the implant?
Immediate loading
What must be done once abutment is placed?
Cover screw with cotton plug to allow access if needed
What is the term for a restoration retained by a screw that must be torqued into place?
Screw retained prosthesis
Are screw holes left uncovered for bar retained dentures?
Yes
What type of cement is recommended for cemented prosthesis?
Temporary cement
Major concern with posterior implant and restoration?
Access ( vs. esthetics for anterior restoration)
Single (implant-supported) crowns are prone to what?
Rotation
What can be done posteriorly to adjacent teeth to increase contact area and aide in improving implant prosthesis stability?
Flatten contacts on adjacent teeth
A posterior crown should have what buccolingual width and why?
Reduced buccolingual dimensions to minimize biting force
Contact points for occlusion should be placed how on the implant prosthesis?
To direct along long axis of implant
What are 2 negative things single units are associated with?
- Minimal retention
2. High risk of uncementation
What type of impressions are made with screw retained crowns?
Implant level impressions
What is the only system where the delivered crown could not be different than on the model?
Internal friction system
What is an impression type to take for anterior implants?
implant level
What is an abutment that is preferred for anterior implants?
Custom abutment or large prefabricated abutment
What abutment shape is desired for anterior implants?
Shaped like cross section of tooth
What is an abutment available for use in the esthetic zone that eliminates the metallic shadow?
Porcelain abutment
What will cause a dark margin with anterior implant?
Margin of prosthesis not apical enough and thereby shows through the thinnest gingival
What should be used to obtain ideal gingival tissue contours?
Provisional crown
What should be seen when provisional first inserted?
Tissue blanching for ~20 min
What is a big consideration when planning a bridge restoration using implants as the abutments?
Due to the fact that there a no ligaments, there must be NO error in path of insertion
What impressions are indicated for implant retained bridges?
Open tray/pickup coping implant level impression
If you modify the implant abutments for a bridge in the mouth, is it advised that those be removed, or should they be provisionalized and remain in the mouth?
Remain in mouth and provisionalize
What is the term used to describe the precise insertion of a bridge into its full position without resistance?
Passive fit
Why is passive fit important to implant supported prostheses?
Because implants have no mobility
What is necessary if sectioning and soldering was done for an implant supported prostheses?
Master impression
How does a resin key work?
Engages coronal portions of abutments while resting on adjacent teeth. Made in lab to help orient abutments during delivery
When delivering multiple abutments, start with which one first?
Most distal first to allow for better visability
What is recommended to minimize nocturnal lateral forces on an implant retained prostheses?
Nightguard
Why is a full arch implant retained prosthesis a whole different ball of wax than what has been discussed?
Nno vertical stop is present and denture setup is necessary
What is required before abutment selection for a full arch implant retained prosthesis?
Wax up containing final teeth positions
Nonsplinted implants prefer what delivery: laboratory or chairside?
Chairside
Splinted implants prefer what delivery: laboratory or chairside?
Laboratory
What type of implants are joined by a bar to enable attachment to a removable prosthesis?
Splinted implants
What is the key to long-term success of the implant prosthesis?
Implant maintenance
What will always exist around the microgap of the implant/abutment connection
Inflammatory infiltrate
What are 3 microgaps and their micron sizes?
External hex connection ~ 40 microns
Internal flat conections ~ 30 microns
Internal conical connections ~ 2-10 microns
What is one of the main goals of long term implant maintenance?
Maintain bone level
The most apical epithelial cell is located how far from most coronal bone cells in implant epithelial attachment?
1 mm
The epithelial attachment around implant is different or the same as around a tooth?
The same (rete pegs and hemidesmosomal attachment)
Is the connective tissue seal around the implant the same or different from that of a tooth?
Different. No transverse fibers
what is the character of the 40 microns adjacent to the implant and how does it act?
Absence of blood vessels, abundance of fibroblasts interposed between thin collagen fibers. Acts like a tight rubber band around implant
What is the character of the area beyond that first 40 microns?
Fewer fibroblasts but more collagen fibers and blood vessels
What does suppuration indicate during implant maintenance checks ?
Indicates hard accretion, most commonly cement. Must be removed
What is the bone level expected when using a two- stage screw type implant?
Bone at first thread
For other types of implants (ones that are NOT two-stage), where should bone level be expected?
2 mm from implant platform
What is an implant problem that is a reversible condition analogous to gingivitis whose main sign is gingival inflammation around implants without evidence of bone resorption?
Mucocitis
What is a common cause of mucocitis?
Abutment loosening
What is a method to detect abutment loosening?
Look for abutment separation on X-ray
What is the most common cause of mobility?
Uncemented crown
Do plaque and calculus gather on implants as they do on teeth?
Yes
If a patient has <3mm sulcus, but bleeding on probing, what should be done?
Disturb biofilm, adjust homecare, recheck in 7-10 days
Can stainless steel instruments be used to scale implants?
No, can scratch titanium leaving nidus for plaque retention
What are acceptable materials for implant scalers?
- Nylon
- Graphite
- Titanium-plated
?Which implant scaler is most effective on tenacious calculus,but manufacturer states they will scratch titanium?
Titanium plated curettes?
What is an implant problem recognized by radiographic or clinical evidence of bone loss?
Peri-implantitis
Implant level impression abutments are selected where?
The laboratory
Which copings remain on the implant when the impression is removed?
Transfer type impression coping
Which copings remain in the impression when removed?
Pick up type impression coping
How do you verify that abutments and crowns are engaging external connection systems?
A combination of clinical and radiographic checks are recommended
For crowns in the esthetic zone, how can soft tissue support be created?
In the abutment and the crown
What is implant indexing?
A method of impression taking at the time of surgical placement
What is passive fit?
The placement of a bridge without resistance
Why should you test if screws can turn without resistance until the last quarter turn?
It is useful for verifying proper fit in multiunit restorations
What is recommended after delivery of a screw-retained bridge?
Block the screw access hole with a temporary material
What does mobility of an implant-supported crown generally mean?
Loosening of an implant component
Which component of a removable prostheses may need to be replaced during maintenance?
The female component
When using two-stage implant, where is the radiographic bone level expected to be?
At the level of the first thread
Clinical inflammation around a single restored implant, associated with pain or pressure but no radiographic bone loss, is most likely due to what?
Loosening of a component
If an implant has been placed apically, a 7 mm peri-implant probing shows no sign of inflammation, and there is no radiographic change and no bleeding, this probably indicates what?
Normal functioning
At a maintenance visit, an implant-retained bar is found to be mobile at one extremity. What should be undertaken?
Verify that the screw is loose and place a new one
When observing a routine radiograph for an implant patient, you see a horizontal dark line between the implant and what seems to be the abutment. This is probably what?
A sign of component loosening
Instruments used for maintenance must not be made out of what material?
Stainless steel
If a patient has removable dentures, what generally needs to be done at yearly visits?
Change of female attachments
What should be recommended to patients for home care?
Super-floss or yarn
Oral hygiene instructions for implants should include what specific technique?
Wrap-around
What percent of the adult population endentulous
10% (endentulism rises with age >60)
Is there any significant difference in treatment effectiveness between conventional denture treatment with or without preprosthetic surgery?
No
All implant supported prostheses use how many implants and it is common?
5 or 6 implants. Limited use due to cost and complexity
Which is more cost effective: retain a few remaining teeth to support prosthesis or replace with implants and cover with prosthesis?
Implants
What is the average vertical bone resorption per year in anterior mandible without implants?
0.4mm
Which resorbs quicker: maxilla or mandible?
Mandible 4 times quicker
What type of implant is covered by gingiva at placement, then reexposed at second surgery? It can also be covered by a healing abutment.
2 stage implant
What is the mean annual marginal bone loss around implants?
0.9mm first year, then 0.1mm per year thereafter
Which has best functional efficiency for mandibular treatments: implant borne hybrid, implant overdenture(tissue borne), conventional lower denture?
Implant borne hybrid(90%)>Implant overdenture(tissue borne)(60%)> conventional lower denture (10%)
What is treatment cost difference for implant supported overdenture versus conventional denture?
3 times
Can a patient tell a difference in stability between a 2 implant retained or greater amounts of implants to retain the overdenture?
No
How many implants provide sufficient support for mandibular overdenture?
2
Which implants have more problems: maxillary or mandibular?
Mandibular
What are some problems with maxillary implants?
Thin bone, loose bone structure, large sinus, divergent implant axes, less favorable force distribution
How many implants to use for maxillary implant supported overdenture?
4
What are 3 single unit crown implant restorative options?
- Screw retained abutment
- Stock abutment, cemented crown
- Custom abutment, cemented crown
What are the single unit abutment options?
- Angled
- Straight
- Direct Gold Coping (engaging)
Nobel Biocare Snappy abutment (cementable crown) comes in 4 and 5.5 mm heights and can have what added to them to allow for what type of impression?
Impression coping put on for closed tray abutment level impression than abutment analog put in and cast poured over
What is put on on top of the cottonball once the abutment is screwed onto the implant and before the crown is cemented on?
Fermit
Implants should be offered as what?
An option for replacing missing teeth
What should you not try to do with implants?
Replace all missing teeth
What are 2 things to beware of with implant restorations and really any procedure?
High smile lines and high expectations
What are 4 reasons to provisionalize?
- Esthetics
- Function
- Soft tissue management
- Patient request
What are five things you need to consider yourself during an implant treatment process?
- Is the implant prescription consistent with the treatment plan?
- Is the potential result consistent with the patient’s expectations?
- Do I have a lab with a level of expertise that have good experience (WTF?)
- Clinician comfortable with type for treatment
- Attention to detail and patient selection
