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What types of splits do you know? (+explain)
1.soft splints (Made of silicone – Ideally not to be used in severe bruxists as they may wear through it)
2.hard splints: for reversible treatment (Made of acrylic - Ideal option in severe bruxists bruxists bruxists)
-full coverage: design of choice
ex: michigan (upper jaw) /tanner (lower jaw)
-anterior repositioning splint
or
-partial coverage: allow overeruption of non-covered teeth (Should be avoided as teeth may move and overerupt if worn long)
ex: anterior or posterior
they are avoided
ADV Vs DISADV of Soft splints:
ADV:
- for emergencies such as restriction of mouth opening and taking recording compromised so there’s pain
- cheap
- little equipment needed to get it done
- made from a single alginate impression and its resultant cast with no occlusal record
- protective device
DISADV:
- soft is easily chewable so not good at all for bruxists (can make it worse) and increased pain of masticatory muscles due to working harder - (Made of silicone – Ideally not to be used in severe bruxists as they may wear through it)
- can wear down quicker and may need replacement
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What is the role of splints?
- check patient if in RCP
- test if increase in OVD
- treat TMD patients where the pain is of muscle origin
- prevent toothwear before and after restorative care
- check if pts can wear partial dentures, overdentures or onlay dentures
- pt achieves mutually protected occlusion: ICP=RCP
- protect the teeth or prostheses its covering
How long are the splints worn?
- usually at night time but also can be worn all the time
- worn until the pain is relieved, until the tooth wear is addressed by restorative dentistry or until the pt is in an RCP
- can reduce the time they wear it once stress is reduced
Fabrication technique:
- take alginate impressions and mount in RCP on a semi adjustable articulator maybe using Lucia jig. then open the incisal pin on the articulator to allow 2-3 mm clearance on the posterior teeth
- mark the outline of the splint on the cast so that the buccal covers incisal edges and cusp tips of posterior by 2 mm, where as palatal doesn’t cover the whole palate (1 mm)
- wax up the splint to give max even occlusion in ICP
- add canine ramps to give disclusion of all other teeth in lateral movement (posterior not in occlusion in this movement)
- posterior disclusion in protrusion with as many anterior teeth in occlusion as possible
- waxed cast is flasked, packed
- is needed add denture anterior teeth if absent
- a heat cure clear acrylic splint is made
How to check if patient wears the splint?
- lightly blast the occluding surface with 25micron Al2O3 to allow easy marking when checking occlusion in mouth
- leave lightly blasted when pt is dismissed to check working and non-working side interferences in function
- if these areas show as polished when they return: they have worn it, if not then they haven’t had it in
TMJ =
articulation b/w condyle of mandible and squamous portion of temporal bone
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which muscles are involved in the elevation of the mandible?
Medial Pterygoid
Masseter (most powerful)
Temporalis
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which muscles are involved in the depression of the mandible?
Lateral pterygoid (inferior head)
Syprahyoids – digastric, geniohyoid, mylohyoid, stylohyoid
Infrahyoids – sternothyroid, sternohyoid, omohyoid & thyrohyoid
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which muscles are involved in the protrussion of the mandible?
Inferior head of lateral pterygoid
Superficial layer of masseter
Medial pterygoid
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which muscles are involved in the retrusion of the mandible?
Superior head of lateral pterygoid
Deep layer of masseter
Posterior portion of temporalis
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TMJ Dysfunction/Myofascial pain:
Joint associated Problems Vs Muscular Problems:
Joint associated Problems:
- Pain localized to joint (easy to detect)
- Joint noises
- Abnormal/limitation of movement due to internal derangements
Muscular Problems:
- Poorly localized/diffuse pain (not easy to detect))
- No joint noises
- Abnormal/limitation of movement due to muscles
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Aetiology of TMD/ Myofascial pain:
Joint overloading Malocclusion / alteration of occlusion Arthritis Psychological factors Multifactorial Trauma Parafunctional habits
Extend and severity of symptoms UNRELATED to aetiology
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What would be the ideal treatment for a TMD patient?
- Reassurance and Explanation - Counselling alone reduces symptoms
- Conservative management (soft diet, jaw rest, cut food into smaller size)
- Physical therapy (exercises, head, acupuncture, OCCLUSAL THERAPY)
- Cognitive Behavioral Therapy (can help you manage your problems by changing the way you think and behave)
- Medications (NSAIDs, Anti-depressants, Botox) -ibuprofen
- Surgical management
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Enamel fracture:
=
Clinical Finding:
Treatment:
= uncomplicated crown fracture
-Clinical Finding:
loss of enamel with loss of tooth structure, dentin not exposed, no tenderness, no vitality lost
-no sensitivity
-Treatment:
if visible fragment then bond to tooth or contouring of restoration with composite resin depending on the extent and location of fracture
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Enamel – dentin fracture:
Clinical Finding:
Treatment:
-Clinical Finding:
A fracture confined to enamel and dentin with loss of tooth structure, but not exposing the pulp, positive sensibility test
-Treatment:
if visible fragment then bond to tooth or contouring of restoration with composite resin
=> if exposed dentin is w/in 0.5 mm of the pulp, place CAOH base as a liner (on top of the pulp)
-test if there is any pulp involvement; there might be irritation
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Enamel - dentine - pulp fracture:
Clinical Finding:
Treatment:
-Clinical Finding:
A fracture involving enamel and dentin with loss of tooth structure and exposure of the pulp sensitive to stimuli
-Treatment:
CaOH placed on pulp, RCT/pulp capping/pulptomy
=>if visible tooth fragment bond it to the tooth
=>future treatment: crown
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Concussion:
=
Treatment:
=An injury to the tooth - supporting structures without abnormal loosening or displacement of the tooth, but with marked pain to percussion
-tender to touch or tapping
-Treatment: NO
monitor pulpal condition for at least one year
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Subluxation (loosening):
=
Clinical Finding:
Treatment:
= An injury to the tooth - supporting structures resulting in increased mobility, but w/o displacement of the tooth
-Clinical Finding:
tender to touch or tapping
bleeding
-Treatment: NO
flexible splint to stabilize the tooth for patient comfort for 2w
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Extrusion:
=
Clinical Finding:
Treatment:
= Partial displacement of the tooth out of its socket
-Clinical Finding:
elongated, excessive mobile, negative sensibility tests
-Treatment:
reposition tooth by gently reinserting it into socket, stabilize it for 2w, RCT
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Lateral luxation:
=
Clinical Finding:
Treatment:
= Displacement of the tooth in a direction other than axially. Displacement is accompanied by comminution or fracture of either the labial or the palatal/lingual alveolar bone
-Clinical Finding:
displaced in P/L direction, immobile, high metallic (ankylotic) sound on percussion, fracture of alveolar process and loss of vitality
-Treatment:
reposition it with fingers or forceps in original position, stabilize it for 4w using flexible splint, monitor pulpal condition, RCT
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Intrusion (central dislocation):
=
Clinical Finding:
Treatment:
=Axial displacement of the tooth into the alveolar bone. This injury is accompanied by comminution or fracture of the alveolar socket
-Clinical Finding:
immobile, high metallic (ankylotic) sound on percussion, negative sensibility test
Treatment:
allow eruption w/o intervention if it is intruded less than 3 mm, if no movement after 2-4w reposition surgically or orthodontically before ankylosis develops
=>if tooth intruded 3-7 mm reposition surgically or orthodontically
=>if tooth intruded beyond 7 mm reposition surgically
=>pulp will become necrotic in teeth with complete root formation, RCT using temporary filling with CaOH 2-3w after repositioning
=>once intruded tooth has been repositioned surgically/orthodontically, stabilize with a flexible splint for 4w
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Avulsion (exarticulation) and its treatment:
=The tooth is completely displaced out of its socket
-pick it, lick it, stick it (NOT with primary teeth b/c it will lead to ankylosis which will cause problem with permanent teeth later on)
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What are the problems with dentine pins?
- cause stress in the dentine leading to micro cracks (weaken the tooth further), which in turn cause microleakage, then caries. this causes failure of restoration
- do not bond with amalgam alloys or composite
- don’t fill the whole prep depth so a space will be left and bacteria can accumulate
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Nayyar Core:
What is it?
What Materials can be used to fabricate a nayyar core?
Which is the ideal for it?
= a post for posteriors and badly broken down teeth
Materials:
-AMG IDEAL !!!!!
-composite
(NOT GIC)
- needs 2-4 mm coronal GP removal !!!!
- drilling of 4 mm into each remaining RCs with a rose head or GG bur and then all canals and the pulp chamber are packed with AMG or composite and crown built up
- know morphology to built up full contour
- use of rubber dam and matrix
- condensation of AMG into canal orifices
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POST AND CORE:
Dental post Vs Dental core:
Core:
=a substructure, which replaces missing coronal structure and retains the final restoration
-can be placed in any tooth
-composite mostly (bulk)
-if enough natural tooth structure exists that it can be relied upon to securely hold and retain the core, then no post is needed !!
Post:
=a metal or other rigid restorative material placed in the root of a non vital tooth
-helps to anchor the core on the tooth !!
-can only be placed in a tooth that had RCT
-if more than half of a tooth’s original crown portion has been lost, a post is needed to assist in anchoring the core to the tooth
-offers no reinforcement benefit and its placement can weaken a tooth and lead to fracture
-made of metal or metal free carbon fiber posts
-used only when there is insufficient tooth substance
-its width should be established by the width of canal after RCT
-Increasing post diameter in an effort to increase retention is not recommended, as this creates unnecessary weakening of the remaining tooth structure
-post should not be more than 1/3 of the canal width otherwise there is increase chance of fracture
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What is the ideal length for a post?
- post length equal to 3⁄4 of RC length if possible or at least equal to the crown length
- 5 mm of GP should remain apically to maintain an adequate seal
- post should always be subcrestal (under the bone level). if it ends above bone level the higher risk of fracture
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Cast post and core: indirect Vs direct methods:
Indirect method:
-Office: remove temporary filling, preparation and then impression of the post space, adjacent teeth and gingiva is taken
=>light body impression material will be inserted into RC with a specific file: the Lentulo file carrier/ Spillar fillers
-the impression is then used to construct a suitable post in the Lab
-next appointment: fix post and core on tooth
-better
-cast post needed
-sufficient time
Direct method:
- Office: prep and fabrication done in 1 appointment
- a resin pattern is produced by placing a preformed plastic “burnout” post into the post space and a resin material/wax is used to built up the tooth to the proper dimensions
- When this is completed, the pattern post and core is removed from the tooth structure and sent to the lab. The technician will make a duplicate of the post and core using alloys or zirconium
- Cementation: After completion, the lab sends the post and core to the office for the definitive cementation.
- Cast post and cores are cemented inside RCs with dental cement or composite resins. The materials are placed inside RCs with Lentulo files
- more time needed
- the dentist decides how he wants the post, not the lab
conclussion from revision lec:
Indirect: Post and core fabricated in the laboratory (Usually involves the cast post)
Direct: Post and core fabricated chairside Direct: Post and core fabricated chairside (Usually involves fibre composite post and bulk filled composite for the core)
The is also the direct/indirect method where duralay or wax is used to make an exact representation of the post and core system this is send laboratory which is then made into a cast post and core
Rule in prefabricated post and core design:
use the narrowest and longest post possible with a smooth surface because it will decrease the risk of failure
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How to decide which post is the ideal: Direct / Indirect (TIP):
It all comes down to the amount of ferrule present!
2-3 mm ferrule (height): indirect cast post
- impression
- ask the lab to do a post and core in 1
- cement it
≥ 3-4 mm ferrule: direct post
- 1 day appointment
- clinicians preference
For molar teeth its best to consider a Nayyar core instead of a post and core
When sulci are normal (2–3 mm) and healthy and bands of attached gingiva are adequate, margins can be placed up to _ inside the sulcus
0.5 mm
How to restore a tooth fractured at or below the crest of bone? / If biological width is 2 mm and ferrule is 2 mm how much do we need?
room must be created b/w future margin of restoration and bone, 2.5 mm needed to accommodate biologic width and 1.5 mm additional required to have adequate ferrule for the restoration
this means that 4 mm of tooth must be exposed above crest bone to satisfy these requirements
this can be done through bone removal etc
In preparing a root canal for a post, the main barrier against reinfection of the periapical region is:
the endodontic obturation material
- leaving 5 mm of undisturbed apical endodontic obturation material after post preparation
What can influence the long term success of the restoration, after post preparation?
The length of the remaining apical seal
What cannot be considered reliable as abutments for fixed or removable dentures or cantilevers or for patients with severe bruxism and clenching habits?
Extensively damaged teeth
What criteria (in sequence) should be assessed after the treatment plan?
ferrule effect
relation between root and crown length
endodontic condition
Classification of teeth with extensive endodontic damage - Class I:
Ferrule effect:
Remaining root length:
Endodontic condition:
Prognosis:
Ferrule effect: Height of remaining tooth ≥ 2 mm at 4 locations (mesial, distal, buccal, palatal or lingual) and thickness of remaining tooth walls ≥ 2.2 mm for an aesthetic restoration or ≥ 1.6 mm for non-aesthetic restorations
Remaining root length: At least as long as the future crown height plus 5 mm for the apical seal
Endodontic condition: Endodontic treatment may be performed without predictable complications
Prognosis: Good
Classification of teeth with extensive endodontic damage - Class II:
Ferrule effect:
Remaining root length:
Endodontic condition:
Prognosis:
Ferrule effect: Height of remaining tooth 0.5–2.0 mm or Width of remaining tooth walls 1.6–2.2 mm with visible margins or 1.2–1.6 mm with non-visible margins
Remaining root length: Less than crown height plus 5 mm but equal or greater than crown height plus 3 mm
Endodontic condition: Without predictable complications or with uncertain results
Prognosis: Moderate
-A tooth in this class should not be used as an abutment. A new evaluation should be performed after endodontic treatment in cases where pre-treatment prognosis is uncertain.
Classification of teeth with extensive endodontic damage - Class III:
Ferrule effect:
Remaining root length:
Endodontic condition:
Prognosis:
Ferrule effect: Height of remaining tooth < 0.5 mm or Width of remaining tooth wall < 1.2 mm at future margin level
Remaining root length: Less than crown height plus 3 mm
Endodontic condition: With irreversible complications
Prognosis: Poor
-A tooth in this class is not a candidate for treatment; it should be extracted and replaced by a prosthesis
When do classes raise or decrease by 1?
aesthetic concerns: increases by 1
Concern about special stress patterns (bruxism, abutments for a RPD, cantilevers, extensive bridges or secondary abutments): raises the class level from I to II or from II to III
In cases where there is no occlusal issues, the antagonist is a removable denture or small/no loads over the remaining tooth: decreases by 1
For patients with poor OH, uncontrolled periodontal disease or caries, an extensively damaged tooth should be considered Class III
-Pre-prosthetic treatment may affect the initial classification
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Tooth Restorability Index:
- to assess how much tooth structure is left to restore a tooth !!!!!!!!
- provides a structured assessment to evaluate remaining coronal tissue (remaining dentine for retention and resistance)
- 6 equal sextants: 2 proximal, 2 buccal and 2 lingual
- TRI allowed scores: 0-3 in each tooth sextant, with a max score of 18 per tooth !!!!!!
- Disadvantage: Subjective to clinician’s opinion of assessing each sextant
- TRI > or equal to 12: acceptable
- TRI 9-12: questionable
- TRI < 9: unacceptable to retain a plastic core: consider: crown lengthening or cast post and core
0 Tooth Restorability Index:
- None
- 2/3 or more of the tooth sextant there is no axial wall of dentine or any dentine above the finishing line is lacking in height as to be unable to contribute to retention and resistance of a core or crown
1 Tooth Restorability Index:
- Inadequate
- Coronal dentine present in the tooth sextant but, it is insufficient to make predictable contribution to retention and resistance.
- Dentin walls that are less than 1.5 mm thick or more than twice as high as their thinnest part would be included in this category.
2 Tooth Restorability Index:
- Questionable
- More dentine is present than in 1, but in one’s clinical opinion it is not possible to be confident whether or not it will make a predictable contribution to retention and resistance
3 Tooth Restorability Index:
- Adequate
- There is sufficient coronal dentine in terms of thickness, height and distribution that this sextant will contribute fully to retention and resistance of the core and final restoration
What is a veneer?
uses:
= a layer of tooth cover material that is applied to tooth to restore localized or generalized defects and intrinsic discolorations
uses:
- teeth that are stained and can’t be whitened by bleaching
- chipped or worn teeth
- improve the appearance of rotated or misaligned teeth
- uneven spaces or diastemas between teeth
- ability to lengthen anterior teeth
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3 Components of composite resin:
Organic Matrix – a plastic monomer/resin material forms a continuous phase and binds filler particles (via a coupling agent)
INORGANIC filler – reinforcing particles and/or fibres dispersed in the matrix
Coupling agent – bonding agent promotes adhesion between filler and resin matrix
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Filler component in Composites:
Macrofilled Microfilled Hybrid Nanofilled Bulk
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For a posterior tooth we can use which filler component?
(for a molar or a post and core tooth)
BULK (ideally)
hybrid
(macrofilled)
- you need a combination of these particles
- bulk most of it and then hybrid at the top
- bigger size of particles
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For an anterior tooth we can use which filler component?
NANOFILLED (ideally)
macrofilled
hybrid
-need small size of particles so that they are polishable easily
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Composite Vs Ceramic:
Ceramic:
ADV:
Offer better inherent color and natural look
Less staining
Longer long-term survival compared to composite
Wear and abrasion resistance is high
Ceramic veneer allows good transmission of light
Better aesthetics
Very much depended on the laboratory skills
Tissue tolerance is excellent
DISADV:
Expensive
Very much depended on the laboratory skills
RISK OF SENSIBILITY problems and devitalization
Can be more destructive compared to composite
Needs at least 2 appointments
Technique sensitive (provisionalisation and cementation)
Composite:
ADV:
Faster; 1 appointment
Cheaper for the patient
Result immediately visible; what you see is what you get
HIGHER IMPACT STRENGTH (protects the antagonist by reducing the occlusal force)
Abrasion values comparable to those of natural teeth
Translucency (sometimes more options than ceramics)
Chemical bonding to all substructure materials
Repair of chipping for all veneering materials
Transition areas toward repairs not visible
Very much depended on clinician’s expertise + skills
Removes less tooth structure (more conservative than ceramic)
Reversible
DISADV: tend to discolor WEARS MORE marginal staining shade matching is difficult often require repair and replacement moisture sensitive (good moisture control is needed) very much depended on clinician’s expertise and skills expensier for dentist weak restoration because layering technique used creates a weaker, more porous work on tooth leaking cost more for the
direct Vs indirect (ceramic or composite) restorations depends on:
the age of the patient
the aesthetic requirement
the probability of the result
the difficulty of conception and longevity
direct option: depends on the clinicians expertise and type of composite
indirect option: as long as a good preparation and impression is taken then it mainly comes down to the expertise of the lab technician
-When preparing one tooth in the aesthetic zone is far more complicated than preparing a pair
Factors influencing perception of colour:
Light source: illuminates the object
Object: reflects, absorbs or transmits light to the observer
Observer: perceives reflected light
The shortest and longest wavelengths visible to the eye are:
shortest wavelength: violet
longest wavelength: red
The retina of the human eye contains 3 types of specialized cell, photosensitive to:
short wavelength:
medium wavelength:
long wavelength:
short wavelength: blue
medium wavelength: green
long wavelength: red
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Hue:
= the quality to distinguish one colour family from another
- corresponds to the wavelength of the light reflected by the teeth
- ex: red from yellow, green from orange
SOS !!!!!
Value:
= an achromatic measure of the lightness or darkness of a particular colour, ranging from pure black to pure white
High value → Light shade
Low value → Dark shade
-most important factor in colour determination and colour characteristic in SHADE MATCHING:
If it is not possible to achieve a close match with a shade guide, a lighter shade should be selected because it can be stained more easily to a lower value. It is impossible to stain a tooth lighter (higher value) without producing opacity
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Chroma:
- The degree of strength or saturation of a colour of particular hue
- describes the intensity or vividness of color
- the higher it is, the more vivid/density it is (dark)
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What kind of shades guides do you know?
- Vita Classical: (most commonly used; theocharides)
-based on hue:
A = reddish-brown B = orange-yellow C = greenish-grey D = reddish grey
with sub-classes of varying value and chroma - Ivoclar Chromoscope:
-also based on hue:
1 series = cream
2 series = orange
3 series = light brown
4 series = grey
5 series = dark brown
- value and chroma - VITA SYSTEM 3D-MASTER: (theocharides)
- based on the 3 dimensions of colour, emphasizing value as the most important dimension in colour matching
- here is where you need to know chroma, value and hue
- most advance, difficult and expensive
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If you chose an indirect restorative option what info would you include in your prescription?
patients details - id, birth date, tel, initials/name
dentists details - tel, address, name
specify which tooth you are requesting for a crown
specify if crown will be full coverage or partial coverage
specify what material the crown will be made of
design
what pontic design
Diagram / Illustration of prosthesis/ drawing
Impressions: Working and the opposing arch
FaceBow record (if needed)
Interocclusal record
Shade Mapping
Indices
Wax Ups (if available)
disinfected impressions or not
delivery date
send date
Size
Shape
Line angle of Tooth
Embrasure Space
Contact Point
Surface enamel details: perikymata, enamel infractions, crazing, fluorosis
Take photos
state which shade guide you are using
Identify where you want the finish line
Shiny or Matt Surfaces
Finishing of Fit Surface
Indirect method: Always state that you would like the post with the core separated from the crown
specify type, design and materials of bridges
Any modifications
indicate porcelain coverage
NOT:
smile line
or if patient has fillers
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What is considered as Biological Failure?
Discomfort, pain or sensitivity Caries Pulp Injury Periodontal breakdown Occlusal problems Tooth perforation Tooth fracture
Biological factor:
Which factors can lead to Caries?
Open margin
Short margin
Over-extended margin
Incomplete removal of caries during previous treatment
Poor oral hygiene
Wrong type of restoration used, promoting caries development
Xerostomia
Biological factor:
Which factors can lead to Pulp Injury?
Improper use of coolant
Over reduction leaving insufficient dentin protective barrier
Minute pulp exposure (to protect it: CaOH or GIC)
Use of irritating luting cement
Improper or no use of temporary prosthesis
Recurrent caries under restoration
Biological factor:
Which factors can lead to Occlusal Problems?
Premature contact in centric and eccentric occlusion leads excessive tooth mobility (occlusal trauma)
You might get - Loss of function: They don't function in occlusion They have no contact with opposing teeth They have permanent contact Over carved or under carved occlusal surface Loss of opposing/approximating teeth
Biological factor:
Which factors can lead to Periodontal Breakdown?
Patients complain of:
Mobility of abutment teeth that may eventually lead to loss
Pain which prevents mastication
Bad odour and taste
May present pocket formation or periodontal abscess
Periodontal breakdown may be due to:
Periodontally affected abutment teeth
Inadequate abutment teeth to support prosthesis
Poor Oral Hygiene
Poor marginal adaptation
Over or under contour of axial walls
Extensively large connectors that restrict the cervical embrasure
Pontic with large contact area on edentulous ridge
Improper or absence of proximal contact causing food impaction and periodontal pocket formation
Irregular or rough margins of prosthesis
Biological factor:
How are Tooth perforations made?
due to:
instrumentation (RCT)
post preparation
Biological factor:
How a Coronal Fracture is caused?
Lack of coronal tooth structure
Recurrent caries
Non-retained restoration
Presence of occlusal interference
Application of excessive force during cementation
Incorrect removal of cemented restoration
Trauma
Biological factor:
How a Root Fracture is caused?
Excessive widening of root canal during endo treatment or post preparation Forceful seating of post Caries extended to root surface Trauma Removing a crown without a sectioner
Biological factor:
How Discomfort, Pain or Sensitivity are caused?
Excessive pressure on soft tissue – caused by incorrect pontic/ridge relationship, overextended prosthesis margins or foreign body pressing on the ridge
Traumatic occlusion – Premature contacts
Torque - Due to absence of parallelism of abutment teeth or absence of temporary prosthesis (too much pressure on teeth which aren’t parallel)
Hypersensitivity – Due to under or over exposed margins of prosthesis, possible cervical caries or over displacement of gingival tissue during impression taking
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Mechanical Failure:
Cementation failure: looseness or dislodgment of restoration could be due to:
- Cement failure
- Retention failure
- Occlusal problems
- Different degree of abutments mobility
- Restoration failure (retainer, pontic, or connector)
- Occlusal wear or perforation of the prosthesis
Mechanical Failure: Cementation failure:
How a Cement failure is caused?
Incorrect cement selection
Clinician not following cementation protocol
Expired cement
Incomplete removal of temporary cement
INADEQUATE MOISTURE CONTROL
Inclusion of cotton fibers
Insufficient pressure seating / Incorrect seating
Mechanical Failure: Cementation failure:
An ideal luting cement would have the following properties:
Adequate working time (gives you time to work)
Adhere well to both tooth structure and metal/porcelain surface (good adhesion)
Provides a good seal
Non-toxic to the pulp
Has adequate strength properties
Be compressible into thin layers (seals better is its compressed into thin layers since there won’t be any gaps)
Has low viscosity and solubility
Exhibit good working time and setting properties
Mechanical Failure: Cementation failure:
How are Occlusal Problems caused?
Occlusal interference
Parafunctional activity
Possible perforation occlusally caused by occlusal adjustments
Loss of occlusal contacts
Mechanical Failure: Cementation failure:
How is Retention failure caused?
Insufficient clinical crown
Over tapered preparation
Ill fitting prosthesis
Misalignment
Mechanical Failure:
How to check cementation failure:
By pushing (apical pressure) on the prosthesis you can see/touch to feel the formation of air bubbles around the margin of the crown
By pulling the prosthesis you will detect movement
Be careful and differentiate if the movement is from the prosthesis or from the tooth itself
Mechanical Failure:
Restoration Failure:
Perforation
Marginal discrepancy
Veneering separation, fracture or wearing
Mechanical Failure:
Connector failure: (more on ceramic or zirconia bridges)
Improper designing of connector size and position
Thin metal at the connector
Incorrect selection of solder
Porosity
Mechanical Failure:
Occlusal wear or perforation of a restoration due to:
Heavy chewing, clenching or Bruxism wear of restoration leading to:
Perforation of occlusal surface of the metal restoration resulting to:
Leakage, cement dissolution & caries
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Aesthetic Failure:
Improper shade matching
Insufficient tooth reduction
Disharmony between restoration and adjacent teeth
Improper masking of metal by aesthetic material
Use of improper shade of cement with all ceramic restoration
Unnecessary display of metal in case of partial veneer metal restoration
Improper marginal adaptation, form, roughness, or extension which lead to gingival inflammation causing unnatural soft tissue color
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Maintenance Failure:
Poor OH and improper maintenance of any prosthesis
The patient must be informed about his responsibility in success or failure of restoration since it can be their fault as well
They need to visit the office every 6 m for a check up
The dentist must recall the patient for periodic clinical and radiographic examination to detect early any harmful changes that might occur
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2 main categories of implants:
Tissue level Implants:
- Smooth surface: allows soft tissue adaptation (=collar which is polished)
- Rough surface: goes in bone
- threads
- connectors
Bone level implants:
- has ONLY Rough surface
- threads
- connectors
-bone doesn’t adapt with smooth surface, only with the rough
- SOS
* What is an osseointegration?
= direct structural and functional connection between ordered living bone and the surface of a load-carrying implant
/ the biomechanical phenomenon whereby clinically asymptomatic rigid fixation of the implant is achieved and maintained in bone during functional loading
tear of blood vessels implant goes inside immediately friction - primary stability (need to check if we have this otherwise we cant place the crown; we will need to wait) osteoclasts remove bone new bone formation secondary stability
Osseointegration process:
-When placing the implant the drill perforates the bone architecture and ruptures blood vessels
-The defect created in the bone is quickly filled with blood
-Primary Stability: the only force that keeps the implant in place (at the moment)
-During the first minutes, blood starts to irrigate the area providing resources for healing
-Ions & proteins start to adhere on the implant’s surface. The bleeding eventually stops, due to the action of platelets which adhere to damaged blood vessels
(Healing process):
-Platelets release substances that promote cell division
-The clot fills the wound creating a provisional matrix that also adheres to the implant
-During the first hours immune cells clean the tissue debris and bacteria present in the wound
-Substances released from platelets increase the vascular permeability allowing leukocytes to move through the spaces created by endothelial cells
-Leukocytes & Ma move through the area destroying bacteria and releasing digestive enzymes
-The wound at this stage can follow its normal healing process OR develop a toxic environment which can lead to implant failure
-Days after surgery, fibroblasts migrate into the wound
-Collagen is synthesized and there is formation of new blood vessels. This restores the oxygen supply, thereby promoting tissue healing
-7 days after the surgery osteoclasts adhere to the residual bone, resorbing it and creating space for the formation of new bone – This will initially reduce the implant stability
-Osteoblasts migrate at the implant surface which after the first weeks, primary bone begins to form at the implant surface – This promotes Secondary Stability
- > if an implant after its placement its spinning it means there is a few primary stability
- > secondary stability checked with specific instruments
SOS
Factors affecting Osseointegration:
Implant material Implant design Surface properties Status of the bone Surgical technique Implant loading conditions
ex: a wider implant won’t have an effect on it
Surface properties:
Hydrophilic implant:
faster osseointegration but expensive
-for anteriors (not for posteriors)
SOS
Bone Quantity:
Bone Width =
Bone Height =
Bone Width = amount of bone present in width
e.g. buccally-palatally
Bone Height = amount of bone present in height apically-coronally (how much height we have)
SOS
Bone Quality:
type 1:
type 2:
type 3:
type 4:
Type 1: Dense bone
Type 2: Compact bone
-The best bone for osseointegration as there is good cortical bone for primary stability and better vascularity than type 1 !!!!!!!
Type 3: Cortical bone
Type 4: Spongeous bone
- you need to worry about it is really soft
-Bone Quality is related to the degree of bone density present
SOS
Indications for implants:
Replace missing tooth / teeth
Mandibular complete overdentures (where retention is a problem)
Long spans – where bridges are not appropriate and the patient wants a fixed option
Trauma cases
Oncology treated cases
Poor tolerance of dentures (gag reflex / burning mouth)
Orthodontic anchorage
(Implant Retained crown
Implants used in Orthodontics
Implant Supported Overdenture
Implant Retained bridge)
SOS
Contra-Indications for implants:
Too young (before full growth is completed)
Large amounts of soft and hard TISSUE LOSS
Psychological disturbances
Active periodontal disease (and increased risk of failed osseointegration)
Bisphosphonates (IV higher risk than oral)
Uncontrolled diabetes
Active cancer therapy (radio- and chemotherapy)
Bruxist
Pregnancy
SOS know it !!
Implant Retained Crown Vs Conventional Bridge
Implant Retained Crown:
ADV: adjacent teeth not affected, easier to clean, preserves bone at site of extraction
DISADV: surgical procedure involved, more technique sensitive, expensive, long-term maintenance
Conventional Bridge:
ADV: FASTER option, applicable in medically compromised patients
DISADV: adjacent teeth prepared, expensive, increased chance of bone loss at site of extraction
Prognosis for both:
- Both have excellent long-term prognosis
- Both can have excellent aesthetics
SOS
Which factor would NOT affect the success of the implants?
anything other than what is on the list
factors that would affect: selecting the right patient operators skills smoking or not quality and quantity of bone available patients OH absence of pathological infection
SOS
Before deciding the dimensions (length and diameter) and the type of implant (tissue or bone level implant) we are going to place, we need to make a consideration and analysis of:
- the bone volume present (using the CBCT)
- anatomical landmarks (nerves, roots, pathologies present)
- measurements of the mesio-distal and bucco-lingual edentulous space !!!!!!
How to place an implant?
according to the difficulty and to the clinicians preference and skills:
Non-guided:
- need to raise a flap to have a view
- you just go in and place the implant
Semi-Guided Surgery:
- very easy
- plastic retainer, cut it at the back (it’s a template/surgical guide to help/guide you were to place the implant)
- take impression and send to lab to wax up to know where the contour of the crown is and create this plastic retainer
- on day of surgery you just position the plastic there (like a night guard)
- surgical guide is extended to as many teeth as possible for stability (m or d)
- doesn’t have sleeves, it’s a plastic with a hole at the back
- semi b/c a little bit of error
- ex: you are worried that the thickness is a little bit at the edge so you have to go at least for a semi guided and raise flap
Fully Guided Surgery:
- no need to raise flap
- extra costs; expensive
- 3D printed
- w/ sleeves (w/o them it wont be an accurate guided surgery)
SOS
Mesio-distal spaces:
How deep the implant needs to be positioned? (corono-apical positions)
For a tissue level implant:
For a bone level implant:
An interproximal distance of at least 1.5 mm between the implant and perio attachment of adjacent tooth
The ideal corono-apical position is slightly different between tissue level and bone level implants:
- For a tissue level implant: the implant collar is positioned 2 mm below the future gingival margin
- For a bone level implant: the implant is placed at a distance of 3 mm below the future gingival margin
It is important to consider the horizontal biologic width around the implant
Surgery (Implant placement):
Step 1 – Prepare the alveolar ridge
Carefully reduce and smooth the ridge and mark the entry point
Step 2 – Mark the implant axis
With the smallest drill mark the implant axis by drilling to a depth of about 6 mm. Insert the depth gauge to check for correct implant axis orientation – you may choose to take a radiograph as well
Step 3 – Prepare the implant bed to full length (2.2 mm diameter)
Pre-drill the implant to the final preparation depth with the smallest drill (pilot drill)
Step 4 – Using a sequence of dills to reach the ideal width, with decreasing speed (to reach the final preparation depth). A depth gauge is used to check the depth.
Step 5 - Profile drill
Depending on the type of implant the appropriate profile drill is used to shape the coronal part of the implant bed.
In very dense bone an addition ‘drill’ is used that is known as the tapping thread.
Step 6 – Implant Placement
The implant can be inserted with a handpiece or with a ratchet
-with these you check the stability
-comes down to clinicians preference
Step 7 – Removing the implant carrier
The holding key, the ratchet and the implant carrier are all removed once the implant has been placed at full length
Step 8 – A healing cap or cover screw placed
This cap is to make sure that the inner part of the implant is protected while we allow the implant to osseointegrate and the soft tissue around it to heal
-Healing cap risky for bacteria leakage so with guided you need to close
-healing cap = comes above the soft tissue level so the implant is exposed to the env
-cover screw = close the flap completely and won’t be exposed to the env until it is ready
Step 9 – Closure of the wound
The soft tissue (mucoperiosteal flap) is adapted back to position and is sutured together to allow healing.
Note: this stage may vary depending on the loading protocols and if a one stage surgery or two stage surgery is followed
Types of Implant surgeries:
1 Stage Surgery:
- healing cap placed at the time of surgery (it is showing so stitch the gums around it)
- allow 6w-3m to heal (implant osseointegrates with the bone)
- a crown is then placed on the implant
- used when the bone quality is good, guaranteeing good initial implant stability or when cosmetics are not a concern (posteriors)
- you need a very good primary stability to put the cap immediately otherwise do the 2 stage surgery
2 Stage Surgery:
- cover screw placed and the gum completely covers the implant (complete closure)
- 4- 6m after osseointegration there is a 2nd surgery to uncover the implant
- then you add a healing cap
- wait at least 1w to allow soft tissue adaptation
- then proceed with crown fabrication
- used when there is addition of bone or soft tissue during the implant surgery or in very aesthetic zones
SOS
Different times of types of placement:
type 1
type 2
type 3
type 4
type 1: immediate placement !!!!!!
- an extraction socket with no healing of bone or soft tissues
- remove tooth and then go in and place the implant
type 2: early placement - with soft tissue healing
- 4-8 w post tooth extraction !!!!!!
- especially for aesthetics
- remove implant and allow those 6 w to lose the bone and then go in and place an implant
- a post extraction site with healed soft tissues but without significant bone healing
type 3: early placement - with partial bone healing
- 12-16 w post tooth extractions !!!!!!
- allowed a little bit of bone remodeling
- a post extraction site with healed soft tissues and with significant bone healing
- for posteriors
- better for primary stability
- no rush since posterior area so you can wait for the bone to remodel
type 4: late placement
- more than 6 m of healing post tooth extraction !!!!!!
- a fully healed socket
- ex: when you will remove a tooth, pt is not sure if they want implant or not so you add bone in socket or leave it to heal and then they will decide
Animal Bone grafting material:
Allows your bone to remodel in between for regeneration of bone and then this animal bone will dissolve
And at the same time include the membrane on top of it to cover it (Bio-Oss)
The rough surface of implants is:
A. Due to fabrication errors
B. Not desirable for osseointegration
C. Important to remove at the neck so that gingival plaque does not attach
D. Desirable for improved osseointegration
D. Desirable for improved osseointegration
The first event leading to osseointegration that occurs after implant placement is: A. Growth of new bone cells B. Formation of a blood clot C. Growth of fibrous tissue D. Gingival down growth
B. Formation of a blood clot
between bone and the implant within the first few minutes
C and D are wrong because growth of fibrous or soft tissue would not be replaced by bone and would result in failure
Excessive force on implant crowns results in:
A. Trauma to bone
B. Immediate fracture of implant components
C. Fatigue of implant components, leading to fracture
D. No damage to implants because of their high resistance to force
C. Fatigue of implant components, leading to fracture
A is wrong because although there may be some damage to adjacent bone, the implant complex suffers most.
B is wrong because immediate fracture is unlikely
Panoramic radiographs are useful for:
A. Ruling out bony pathologies and estimating bone availability
B. Performing precise measurements of bone height and width
C. Selecting the height and width of implants
D. Detecting all existing anatomic limitations
A. Ruling out bony pathologies and estimating bone availability
Which of the following statements about bone quality is true?
A. Type 4 bone is the densest bone
B. Type 1 bone is the densest bone
C. There is a direct correlation between bone density and implant survival rate
D. Bone quality is determined precisely based on Hounsfield numbers
B. Type 1 bone is the densest bone
When selecting an implant:
A. It’s best to choose the longest implant possible, because the longest implants survive best
B. It’s best to choose the widest implant possible, because the widest implants survive best
C. Implant surface selection is critical
D. At least 1 mm of bone lingual and buccal of the implant must remain for it to survive
D. At least 1 mm of bone lingual and buccal of the implant must remain for it to survive
SOS
Advantages of implants:
- Fixed replacement
- Good success / survival rates
- Preservation of tooth structure
- Provision of additional support
- Increased retention for removal prosthesis
- Resistance to caries
- Increased confidence
- Improves aesthetics, function and speech
SOS
There are some marks on a hard splint, what do they mean?
Green marks:
Blue lines:
Black lines:
Green marks: Indicate even occlusal contacts
- distribution of the load
- when they bite together
Black lines on canines: Indicate that on lateral excursions the canines are the last teeth in contact (canine guidance/mutually protected occlusion)
-when they move from side to side
Blue lines on anterior teeth: Indicate that on anterior guidance there is posterior disclusion
-when they move the jaw forward
SOS
Which is not an ideal treatment for a TMD pt?
a. reassurance
b. conservative management
c. physical therapy
d. lazer treatment
d. lazer treatment
SOS
If composites are used for a Nayyar core placement, what types of composites do we have regarding filler contents?
bulk (preferably) or hybrid
SOS
How would you apply composite on tooth to get excellent shade matching?
layering
SOS
Besides composites what other materials can be used for Veneers? (be specific)
emax (400MPa)
feldspathic (160MPa)
In Biological failure of fixed prosthesis which of the following is not a common cause of Pulp injury?
a. Improper use of coolant
b. Over reduction leaving insufficient dentin protective barrier
c. Lack of rubber dam use
d. Improper or no use of temporary prosthesis
c. Lack of rubber dam use
You are trying to root canal treat a tooth and you realised that you just made a perforation on the furcation of the tooth. What kind of failure is this?
a. Aesthetic
b. Mechanical
c. Biological
d. Maintenance
c. Biological
SOS
Aesthetic Risk Assessment:
Which patients are at a low risk, moderate risk or high risk for an implant placement?
Site level:
Low risk: thick gingival biotype low lip line healthy, patient has responded very favorably to periodontal therapy with optimal OH Low functional and aesthetic demands No cost-related concerns
High risk: neglected dentition active periodontal disease smoking high lip line many fillings missing 2 or more teeth presence of aggressive or refractory periodontitis high plaque and bleeding on probing scores high aesthetic demands high treatment costs
Site level:
if they have a really bad quality and quantity of bone
SOS
Monolithic Zirconia Crown reductions and margins:
1 mm occlusal reduction
- 5 mm functional cusp reduction
- 5 mm chamfer margin
> 0.7 mm axial reduction
+/- seating grove (1 mm above chamfer margin)
SOS
All Ceramic Crown reductions and margins:
1.5-2.0 mm occlusal/incisal reduction
2.0-2.5 mm functional cusp reduction (only for
molars)
1 mm deep chamfer/round shoulder margin
> 1 mm axial reduction
+/- seating grove (1 mm above chamfer margin)
SOS
Ceramo-metal Crown reductions and margins:
1 mm where metal, 1.5-2.0 mm where porcelain 1.5 mm functional cusp reduction (only for molars) occlusal reduction
> 0.7-1 mm axial reduction
1 mm shoulder margin buccally (where porcelain) and 0.5 mm chamfer margin lingually (where metal)
SOS
Which is the most important factor in colour determination and colour characteristic in shade matching?
Value
When should a post lie subcrestally?
always
-ve sensibility tests:
lateral luxation
extrusion
intrusion
enamel dentine pulp fracture
optimum taper for a crown preparation?
six degrees
