Revision P.3 Flashcards
Posts & Cores
Post:
The post (dowel) is a metal or other rigid restorative material placed in the radicular(root) portion of a non vital tooth. A dowel traditionally made of metal is fitted in to a prepared canal of a natural tooth.
Posts & Cores
Core:
Refers to substructure , which replaces missing coronal structure and retains the final restoration .
- Dental posts should be recognized as simply a way to help to anchor a dental core in a tooth . If enough natural tooth structure exists that it can be relied upon to securely hold and retain the core, then no post is needed
Posts & Cores
How to decide which post is the ideal: Direct / Indirect (TIP)
It all comes down to the amount of ferrule present!
- 2-3mm ferrule (height) you are better off with an indirect cast post .
- ≥ 3-4mm ferrule you can then use a direct post
- For molar teeth its best to consider a Nayyar core instead of a post and core
Posts & Cores
What we have learned from the papers we read on Endodontically treated teeth
- The primary purpose of a post is to retain a core that can be used to retain the definitive prosthesis
- Sorensen and Martinoff reported that coronal coverage did not significantly improve the success of endodontically treated anterior teeth
- Posts do not reinforce endodontically treated teeth and are not necessary when substantial tooth structure is present
- 3-10% of post and core failures are attributable to root fractures
- The length of the post should ideally be 2/3 or 3⁄4 of the root canal
- The width of the post should not be more than 1/3 of the canal width
- There needs to be a minimum of 4-5mm apical GP
- Definitive prosthodontic treatment should be performed on asymptomatic endodontically treated teeth as soon as is practical after completing the endodontic therapy.
Steps for Taking a Shade:
- Take the Shade and Photographs at the Beginning of the Appointment. This Avoids Eye Fatigue & the teeth are not desiccated.
- Turn off the Dental Exam Light
- Use a Neutral Patient Towel (Blue or Gray, Never Yellow)
- Use Color Corrected Fluorescent Lights in Treatment Rooms.
- Set the Chair at 45 degrees and view the patient at eye level and at arms length.
- Be sure there are no shadows present.
- Position Shade Tab in the same Plane as the teeth.
- Squint eyes to use the cones of the eye. The cones are better for value and color than the rods that are being utilized more when you are not squinting.
- After 10 seconds, look at gray or blue before trying another Shade Tab.
Toothwear / Tooth Surface loss
Types of toothwear:
- Attrition
- Abrasion
- Erosion / Acid dissolution
- Abfraction
- Caries
- Iatrogenic
- Trauma
- Know the definitions for each type of toothwear
- Know their clinical features
Toothwear / Tooth Surface loss-How to manage such cases:
If you are planning on restoring the original shape of the teeth how would you plan it?
- Articulated study casts
- Wax-ups
Toothwear / Tooth Surface loss-How to manage such cases:
Why you would choose to have articulated waxed-up study models prior to you proceeding to any prosthesis preparations?
- Demonstrate to patient
- Used as a guide in order to know the extent of the preparation when for example preparing teeth for veneers
- Part of treatment planning, especially when complex treatment in order to view on the articulator
- When planning on increasing the OVD
Digital & Conventional Wax-ups
These are needed when:
- planning complex cases that would involve increase in OVD .
- Also necessary when treating veneer cases .
- Can also be useful to create putty indices when doing composite build- ups or when trying to close diastemas ]
Digital & Conventional Wax-ups
When would you ask the lab to make wax-ups for you?
- To demonstrate the final outcome to the patient and encourage them to undertake the treatment.
- To make provisionals / temporaries
- To create reduction indices
- To assess the size, shape, texture and teeth angulation
- To guide us in gingival contouring (When carrying out gingivecomy or crown lengthening
What is Immediate Dentine Sealing?
IDS is a universal concept whereby freshly cut dentine is sealed with an adhesive system immediately after preparation (before impression) for inlays / onlays / veneers and even crowns.
Which are the reasons for IDS?
- Bonding to freshly cut dentine
- Prepolymerisation thickness and stabilisation of the hybrid layer
- Selective wet dentin bonding
- Delayed loading of the dentine bond
- Decreased bacterial leakage
- Decreased sensitivity during provisional stage
- Decreased postoperative sensitivity
- Improved tooth preparation
- Reinforcement of remaining tooth structure
- Substitution of retention / resistance form
- Strengthening effect on crowns / onlays / veneers
- Facilitated try-in procedures and occlusal adjustments
- Compatibility of adhesive and luting cements
- Use of light-activated products always possible
- Spot bonding of temporaries
- Omission of provisional cements
- Optimal protection of direct pulp capping
- Sealing of endodontically treated teeth
- Two-stage placement of direct restorations
- Protection of root surfaces and biocorroded dentine
Understanding a Dental Implant?
There are two main categories of implants:
Tissue level Implants & Bone level implants
Understanding a Dental Implant?
Which are the main differences between the two types of Implants?
Osseointegration
Summary of Biological events: