fp Flashcards
Arcon Articulators
vs
Non-Arcon Articulators
Arcon Articulators: mimic TMJ more closely by having the condylar path elements (condyles) = lower member and the articular disc components on upper member. This setup resembles the anatomical arrangement of the human TMJ, thus, simulating > jaw movements.
Non-Arcon Articulators: The setup is reversed, with the condylar path elements placed on the upper member and the articular disc elements on the lower member. This type does not mimic the anatomical features of the TMJ as closely as arcon models and is typically simpler in design.
7x factors to consider when deciding which tx option btw RPD, FDP, RBB, IMPLANTS
- Span Length
- Span Configuration
- Abutment Alignment
- Abutment Condition
- Occlusion
- Periodontal Condition
- Ridge Form
- Span Length criteria for
RPD
FDP
RBB
implant
- Span Length
(RPD): Can span > than 2 teeth posteriorly and > 4 anteriorly.
(FDP): Suitable for spans of 2 or fewer posterior teeth and up to 4 incisors.
RBB Typically used for single teeth, occasionally 2 incisors.
Implant-Supported Fixed Partial Denture: Ideal for single tooth and spans up to 6 units.
- Span Configuration criteria for
RPD
FDP
RBB
implant
- Span Configuration
RPD: no distal abutment and multiple edentulous spaces.
Conventional FPD: Uses distal abutments; short cantilever possible.
Resin-Bonded: Mesial and distal abutments to the pontic.
Implant-Supported: No distal abutment req, supports from implant to implant.
- Abutment Alignment criteria for
RPD
FDP
RBB
implant
- Abutment Alignment
RPD: Tolerates tipped abutments and divergent alignment.
Conventional FPD: Accepts <25-degree inclinations with modifications.
Resin-Bonded: Req <15-degree angulation mesiodistally, same inclination faciolingually.
Implant-Supported: Needs close alignment between implant and abutment.
- Abutment Condition criteria for
RPD
FDP
RBB
implant
- Abutment Condition
RPD: Can use short clinical crowns and insufficient abutments.
Conventional FPD: Suitable if abutments need crowns or have significant dental structure.
Resin-Bonded: Prefers defect-free abutments.
Implant-Supported: abutments not req.
- Occlusion criteria for
RPD
FDP
RBB
implant
- Occlusion
RPD: Adaptable to irregularities in a healthy opposing dentition.
FPD: Supports favorable loading conditions.
Resin-Bonded: Cannot be used for incisor replacement if deep overbite
Implant-Supported: Requires occlusal forces to be as vertical as possible.
- alv bone Condition criteria for
RPD
FDP
RBB
implant
- Periodontal/alv bone Condition
RPD: Can use secondary abutments when primary are weakened.
Conventional FPD: Requires good alveolar bone support and no mobility.
Resin-Bonded: Needs stable periodontal support without mobility.
Implant: Demands dense bone for placement.
- Ridge Form criteria for
RPD
FDP
RBB
implant
- Ridge Form
RPD: Suitable for cases with significant gross tissue loss.
FPD: Works well with moderate resorption.
Resin-Bonded: Requires moderate to no resorption.
Implant-Supported: Requires minimal soft tissue defects.
ABUTMENT’S LOAD BEARING EVALUATION
1see … ratio
2 …shape
3 what bears stress?
1 Crown to root ratio 2:3 or minimum 1:1
2Root configuration Preferably broad buccal-lingually; widely separated roots >conical
better periodontal support
3 PDL area > ; can bear more stress
ante law…..
Total root surface-all teeth supporting FPD should equal/exceed total root surface area of teeth being replaced.
BUT NOT a strict rule.
pier abutment when there is ….
An edentulous space can occur on both sides of tooth, creating a lone, freestanding pier abutment
solution to pier abutment acting in middle as fulcrum to unseat retainers on other abutments?
Nonrigid connector: a type of connector that allows for some movement between the parts of a dental bridge to distribute stress more effectively.
T-shaped key: This is attached to the pontic on the mesial side.
Dovetail keyway: Located within a retainer on the distal side. The T-shaped key fits into this dovetail keyway to join the components together.
repair versus replacement factors to consider 5x
1 %S -Prognosis: refers to the likely of success or durability of the prosthesis
2 Medical limitation:
3 Time limitation:
4 Economic limitation
5 EXTent and complexity of damage affect whether it is feasible to repair it.
Pain in post-RCT , post and core +crown done- suspect root fracture// pain in bridge - connector problem - why pain?
pain is attributed to extra force being transmitted to the abutment teeth, leading to discomfort from overloading the periodontal ligament (PDL).
Mechanical Failure of Fractured
porcelain Causes: 8x
1 PREP-overprep=Excessive porcelain thickness without adequate metal support
2 PREP-Insufficient reduction- insufficient interoccl space
3 LAB-Improper laboratory procedures; Microcracks within ceramic
4 Habit=Excessive occlusal parafunction
5 OCCL=Lack of occlusal adjustment causing stress zones on ceramic
6 Trauma
7 material=Incompatible Coefficient of Thermal Expansion (COTE) between metal framework and ceramic
8 Fatigue failure due to environmental factors like masticatory forces, which can cause crack initiation, propagation, and eventual fracture
general Management (Mx) of porcelain #
fractured but the multi-unit prosthesis is otherwise satisfactory, ….to avoid…
If there’s little or no functional loading on the fracture site, fractured porcelain can be bonded using a porcelain repair system with…
If porcelain is fractured but the multi-unit prosthesis is otherwise satisfactory, repair rather than remake might be justified to avoid additional discomfort, time, and expense for the patient.
silane coupling agents (e.g., 4-META) to promote bonding with composite resin (CR). Additional mechanical undercuts in the metal framework to improve CR retention.
steps in repairing # porcelain
1 LA and RDI.
2 Porcelain/metal surface -slightly abrade with high speed diamond bur/micro abrasion.
3 Hydrofluoric acid etchant on crown; thoroughly rinse and dry surface .Porcelain will have a frosted appearance.
4 Apply Silane on the crown and allow to evaporate for one minute. After one minute, air dry.
5 if exposed tooth etch and bonding on tooth- Dry-thin 10 sec with oil free/moisture free air. Prep should appear shiny. Light cure for 10 sec. (20 sec. for lights with output<600mW/cm2 ).
6. Restore with composite of choice+ final cure.
Characteristics of Mutual Protection occlusal scheme
it is Known as…
In centric relation only …tooth contact
In protrusion…
In lateral excursions,
Aims to
canine protected occlusion.
In centric relation, only posterior teeth contact, directing forces along their long axes.
In protrusion, only incisors contact.
In lateral excursions, only canines contact.
Aims to eliminate frictional wear.
Preferred for ease of fabrication and patient tolerance.
Rationale for Mutual Protection (Class 3 Lever System):
The mandible functions as a Class 3 lever:
Joint serves as the fulcrum.
Muscles provide the applied force or force vector.
Teeth or bolus act as the load.
Anterior Teeth: Long, single roots=>Withstand lateral loads; furtherest from fulcrum,reducing lateral forces
Posterior teeth: Multi-rooted=Withstand vertical loads
For optimum stability, comfort, and function, the anterior teeth must be:
1In harmony with the neutral zone
2 In harmony with the lips
3 In harmony with phonetics
4 In harmony with centric relation
5 In harmony with the envelope of function
results in tooth position and contours that are in harmony with functional anatomy that also produces
the most natural esthetics
partial grp fx allows for
Allows some posterior teeth to share the load during lateral excursions, while others contact only in centric relation.
Decisions are made on a tooth-by-tooth basis:
eg If a tooth is weak laterally, it should contact in centric relation only.
Group Function an occlusal scheme where post…share the load during …
Group function is an occlusal scheme where post teeth on one side of the dental arch work together to share the load during lateral movements. This helps distribute the forces exerted during chewing more evenly across several teeth, reducing the risk of overloading any single tooth and potentially leading to less wear and tear or damage.
Facebow eg 2x
Denar Slidematic Facebow- arbitary hinge axis FB
kinematic facebow req for FMR on a fully adjustable articulator