Bridgework 2 Flashcards
What are general indications for bridgework?
Function and stability of dentition
Speech
psychological reasons - rpd can be too much for pt
systemic disease - epileptic pt (seizure resulting in fracture or inhalation)
cooperative pt - good OH, wanting to maintain dental health
What are general contra-indications for bridgework?
uncooperative pt - poor oh, not willing to improve
MH contraidicnations - allergy
Poor OH
High caries + active disease
PD until adressed or improved
large pulps, young teeth - risk of pulp exposure
What are some local idincations for bridgework?
big teeth - greater retention and resistance
heavily restored adj teeth - good for conventional
favourable abutment teeth
favourable occlusion
What are some contraindications (loca) for bridgework?
High occlusal load
tilting and occlusal load
high chance of further tooth loss within arch
poor prognosis of abutment teeth
length of span too long - flex and fracture
ridge form and tissue loss (dente replaces yes soft tissue and hard tissue)
degree of restoration - if not much tooth left after prep
PA status
PD status
What are some types of conventional bridges? (4)
Conventional bridge (fixed fixed or cantliver)
Fixed moveable bridges
Hybrid bridge
Spring cantilever
What is a fixed-fixed bridge?
Retainer –> pontic –> retainer
theres a retainer at eachch end with Pontic in middle (retainer is on abutment teeth)
Where are fixed-fixed bridges most common?
Posterior teeth
When can we use a longer plan bridge?
if pt has class II incisal relationship then there is not much occlusal contact from lower teeth onto upper teeth so teeth not in occlusion so bridge wont be subject to high occlusal forces and wont flex as much
Pt with AOB - upper anterior dont occlude with lower anterior and Pontic is kept clear of occlusion
What are 5 advantages of fixed-fixed conventional bridges?
Robust
Maximise retention and strength as crown is retainer
abutment teeth can be splinted together (good in perio cases with mobile teeth - we can consider fixed-fixed design to splint teeth educing mobility)
Can be used in longer spans (can replace 6 and 5 using 4 and 7)
Lab construction is easy - impression –> lab
Why are fixed fixed conventional bridges more robust?
As we can use larger connectors between abutment and Pontic so more of a solid solution that can withstand occlusal forces
What are 4 disadvantages of fixed fixed conventional bridges?
preparation is difficult (parallel prep for common POI)
Minimally tapepered prep (5-7 degrees) to increase retention
Common POI for abutments
results in extensive tooth tissue removal (risk of pulp exposure)
What happens if abutment teeth are parallel?
if we prepare teeth and preps aren’t parallel technician will make. bridge that has POI largely based on one tooth and as a result wont seat as teeth have different paths of insertion
What is a potential solution if abutment teeth no parallel?
fixed moveable bridge
What issue can fixed moveable bridges fix?
If abutment teeth have different pathos of insertion resulting in us unable to fir bridge due to adjacent teeth interference
to get them parallel wed have to do extensive prep to aspects of teeth which is destructive
What is a fixed moveable bridge?
This is a type of conventional bridgework that consists of two components (we prep two abutment teeth and the teeth have different longitudinal axis and POIs so the bridge comes back in two parts - one initial down goes on one tooth and sits on one POI and other component that has Pontic and retainer on other tooth slides on other way and then these components slide together with male component which goes into female component like a jigsaw piece)
How does a fixed moveable bridge join?
The crown goes onto one tooth
retainer and Pontic on other tooth
there is a slot on the distal marginal ridge of front tooth and mesial aspect of the Pontic which has male component and that slides into female component
What is a cantilever bridge?
This is a bridge that has RETAINER –> PONTIC
Support for Pontic at one end only
can be adhesive or conventional
What are advantages of cantilever bridges? 3
Lab construction straighforward
conservative design compared to fixed fixed conventional
no need for tooth prep to be parallel as only one abutment teeth
What are disadvanatges of cantilever bridges?
Can only be used for short span due to one abutment tooth only (single tooth only)
rigid - more prone to fracture
mesial cantilever preferred (we want abutment more posterior and Pontic more anterior as when pt occludes they go posterior to anterior so if we have it other way around pt will occlude on Pontic first resulting it bridge debunking
How many teeth does a cantilever bridge replace?
1
Where is a cantilever bridge best placed?
Mesial cantilever bridge
this means that the abutment tooth is posterior
pontic tooth more posterior
if we have abutment anterior and Pontic posterior we result in see saw effect and bridgework lifts up (good in SDA case where pt has 4s and we replace 5s as no posterior occlusion behind)
When can we provide a distal cantilever bridge?
whenSDA and using 4s to replace 5s
What is a fixed moveable bridge?
This is a bridge where there is a rigid connector usually at DISTAL END OF PONTIC AND MOVEABLE CONECTOR MESIALLY
What are 5 advantages of a conventional fixed moveable bridge?
Preps dont need Common POI (no need to be parallel as bridge in two parts so more conservative)
Each prep designed to be retentive and independent
conservation of tooth tissue
allows minor tooth movement
can be cement in two parts to click in together
What are 4 disadvantages of fixed moveable bridge work?
length of span is limited - can only replace one tooth
lab construction is complicated
difficult to clean below moveable joint (male and female component connect)
no prov bridge (prep –> perm resto)
How many teeth can a fixed moveable bridge replace?
1
What is a hybrid bridge?
This is where theres one retainer with minimal prep
one retainer with conventional prep
What is advantage of hybrid bridge?
Can have one tooth as crown prep if large resto
and other abutment tooth can be minimal prep and is resin retained
What is the issue with hydrid bridges?
The metal wing on adhesive bridge is likely to de bond first and retainer on tooth that is crowned is robust so pt wont be aware it has debunked and bacteria can leak down palatal aspect and pt returns in pain with caries down palatal aspect
What is a spring cantilever bridge?
This is where there is one Pontic attached to the end of a metal arm that runs across the palate to a rigid connector on the palate side of the retainer
this is an old fashioned dtehcnique which is trying to be conservative of anterior teeth (if already restoration posteriorly we can use that tooth)
What is a spring cantilever bridge used for?
Replacing upper incisor teeth
What are advantages of spring cantilever bridges? 3
useful is there is spacing between upper incisors
good when adjacent teeth are u restored as we dont have to prep
if posterior tooth is already restored and would be good abutment tooth
What are disadvantages of spring cantilever bridges? 4
can only be used for upper incisor teeth
difficult to clean under palatal connectir
can irritate palatal mucosa
difficult to control movement of Pontic as metal arm is springy and can displace palatal soft tissues
How can we assess abutment teeth?
Clinically
Radiographically
must be Abel too withstand force directed from other teeth that are now missing
abutment teeth need to be healthy and free of inflammation and disease (absence of PA pathology and perio disease)
What is crown to root ratio minimum for abutment teeth?
Minimum of 1:1 crown:root ratio
optimum ratio is 2:3 with length of tooth coronal to alveolar crest compared to length of root in bone
we want more root surface area than crown - root to be at least same size as Pontic tooth replacing
short roots - not supportive
