Removable Pros Flashcards
What are the 4 categories of Prosthodontics?
- Removable Pros (RPD, FD)
- Fixed Pros (Crown/Bridge)
- Implant Pros (Implant supported crown)
- Maxillofacial Pros (Prosthetic Eye/Nose, Denture with hard palate)
What are the 2 categories of maxillofacial pros?
Stomatognathic (Teeth/Jaw/Soft Tissue: dentures involving hard palate)
Craniofacial (Head/Neck: artificial nose/ear/eyes)
What is the aim of prosthodontics?
Restoration of teeth + maxillofacial tissues with biocompatible substitutes
What is a prosthesis?
An artificial replacement for an absent part of the human body
What are different types of Removable Partial Dentures?
Acrylic Denture
Chrome Denture
Titanium Dentures
Valplast
What are advantages of acrylic dentures?
Easily Adjustable Simple Design Accommodates Additions Can do as immediate denture Faster (if suitable primary impression) Good if patient's teeth/gum health is variable Cheaper Good wettability (retention via suction)
What are disadvantages of acrylic dentures?
Thicker Less durable Not well accepted by patients Stains Easily (Porous) High fracture rate Plaque retention
What are acrylic dentures made out of?
Denture: Methyl Metharcrylate (MMA)
Clasps: Gold/Stainless Steel
What are advantages of chrome dentures?
Thinner Lighter Stronger - less coverage needed More durable (10 years+) Less Plaque retention Lower fracture rate Less staining
What are disadvantages of chrome dentures?
Additions difficult (unless planned for) More complex More expensive (casting) Conductive of hot and cold Slower (primary + master impression)
What are chrome dentures made out of?
Alloy of chrome and cobalt
What are advantages of valplast dentures?
Better Aesthetics Fast to fabricate Easier for single tooth Less muscle control needed than acrylic More expensive than acrylic Plaque retention Close fitting
What are disadvantages of valplast dentures?
Special cleaning products needed Stains Easily (Porous) Can't use free end saddle Very lab specific Special handpieces and burs needed to adjust chairside
What are valplast dentures made out of?
Biocompatible Nylon + Thermoplastic Resin
What features are examined when doing an extra-oral assessment of an existing denture?
- Type: partial vs full
- Material: acrylic, chrome, titanium, gold, valplast
- Denture experience
- Happy with fit/comfort
- Denture age
- Repairs/Additions
- Wear Patterns
- Denture Hygiene
What features are examined when doing an intra-oral assessment of an existing denture?
- Appearance
- Speech
- Designed
- Extensions: to palate/sulcus (Satisfactory/Under/Over)
- Retention: resist dislodgement (Satisfactory/Good/Poor)
- Stability on function (Satisfactory/Good/Poor)
- Neutral Zone Compatibility
- Freeway Space (IOD)
- Occlusion (CR, CO, Eccentric positions)
What material is used to do additions on acrylic dentures?
Cold Cure Acrylic
Are additions on acrylic dentures noticeable?
Yes, by differences in colour from different rates of staining
What is neutral zone compatibility ?
The potential space in the mouth for a denture between the lips/cheeks and tongue. Poor compatibility will affect mastication and risk of trauma
Adaptation to using dentures requires what 3 things?
Learning
Muscular Skill
Motivation
What are the 14 steps in denture construction?
- Examination + Treatment Planning
- Mouth Preparation
- Tooth Preparation
- Primary Impressions
- Special Tray
- Master Impressions
- Jaw Relations
- Denture Construction
- Check Fit
- Tooth Selection
- Try In
- Insertion
- Post Insertion
- Recall
How do you measure vertical dimension for pros?
Distance between tip of nose (Pronasale) and chin (ST Pog) using Calipers or Willis Gauge
How do assess if speech has been affected by the freeway space (IOD) created by an existing denture?
With denture fitted get patient to say words with S
- Inadequate Freeway Space: clicking of teeth on speaking
- Accurate Freeway Space: articulate S sounds
- Excess Freeway Space: Muffled/Unclear Words
What do we expect freeway space to be in Class I, II and III occlusion?
Class I: 2-4mm
Class II: 6-10mm
Class III: 1mm
How do you calculate freeway space?
IOD = OVD - RVD
Are bite records necessary for all RPDs?
No, if only a few teeth are missing then Centric Occlusion is well established.
What needs to be validated at a Try In?
Patient is happy with current tooth shade and bite
What diagnostic elements can be part of the initial examination?
- Chief Complaint
- Medical History: factors preventing insertion/cleaning
- Dental History: past denture experience, tooth loss, active disease
- Social History: reasons/attitude for denture
- Occlusion
- Study Models
- Radiographs - OPG of full dentition, PA of abutment teeth
- Referral to Specialist Prosthodontist
- Examination of existing denture
What is the purpose of a primary impression?
To create special trays to take the master impression
What are requirements for a good RPD?
- Good/Reliable Lab
- Good Impression taking skills
- Preservation of bone
- Inactive caries/perio
- Satisfactory Oral Hygiene
- Simple/Practical Design
- Patient cooperation/motivation
- Recall/Maintenance Protocol
Is masticatory efficiency improved by posterior RPDs?
No - reduced dentition will focus on mastication on remaining dentition. Replacing missing molars will help control direction of food bolus but does not added to chewing efficiency
What is the philosophy behind RPDs?
Perpetual preservation of what remains rather than meticulous restoration of what is missing
What is displaceable mucosa and why is it an issue for RPDs?
Overgrowth of soft tissue after bone levels from missing teeth shrink back.
Poses an issue because it is not a stable position for free-end saddles - denture movement occurs on contact
Can displaceable mucosa be treated?
Yes, it can be excised by an oral surgeon, but this could result in a bony ridge that is even less comfortable
What anatomy could pose issues for lower RPDs?
Shallow resorbed lower ridges
What anatomy could pose issues for upper Full Dentures?
High Palatal Roof - poor retention form (vertical)
Flat Palatal Roof - poor resistance form (horizontal)
What are anatomical restrictions for dentures?
Mandibular Tori Buccal Exostosis Overeruption Limited Neutral Zone Limited IOD
What denture would you use as transitional or permanent?
Transitional: Acrylic
Permanent: Chrome
What is a Free End Saddle?
Where there is no posterior attachment - only one anchor tooth
What is a Bounded Saddle?
Where are there are anchor teeth on both sides of the saddle
What are the disadvantages of a free end saddle?
Apply considerable pressure on gingival tissue
What is an Occlusal Rest?
A rigid extension onto an anchor tooth that has been prepared to receive it.
The Rest can be a naturally low marginal ridge, but more commonly is a prepared depression
What is the best way to prepare an occlusal rest?
Using a high speed round diamond in order to create a reproducible prep in both the patient’s tooth and master impression
What should a primary impression cover?
Maxilla
- Labial Sulcus including Frenum
- Maxillary Tuberosity
- Hamular Notch
- Hard Palate to the border of the Soft Palate
Mandibule
- Labial Sulcus including Frenum
- Retromolar Pad