trial metal coping

trial metal coping

• is a crucial step in FPD fabrication to ensure the accuracy of fit esthetics and function before final prosthesis completion error to corrected at this stage prevent failure after cementation.

Metal copic

• thin metal substructure fabricated that fit over the prepared tooth abutment in fixed prosthodontics

• it serve as the foundation or framework of a crown of fixed partial denture onto which esthetic material such as porcelain applied later

trial metal coping procedure

• try in and seating

• check marginal fit

• evaluate proximal contact

• check path of insertion

• check occlusion

• confirm framework passivity

common errors

• open margins

• over extended edges

• rocking framework

• tight contacts

Adjustments

• burs for metal reduction

• relieve tight areas

• recheck seating after adjustments

trial fitting

• the process of placing the prosthesis (trial denture) on a patients mouth for evaluation

• the try in the procedure can be accomplished on many patients without administering an esthetic

• the patient unimpaired tactile since can be valuable during the adjustment of occlusion and the annoyance of lingering anesthesia is avoided

• if the patient uncomfortable by the procedure anesthetic should be given

• cementation should be postponed if the patient reports tooth sensitivity under provisional temporary crown

• the tooth would be subjected to greater chemical and thermal trauma upon placement of permanent restoration

• never cement a crown permanently over symptomatic crown

unglazed stage

• chalky appearance is observed

• anatomy must be evident

• adjustment are done in unglazed stage before glazing

glazed stage

• its done to be obtain a smooth surface that stimulates natural tooth surfaces

• cannot or hard to make alteration

• glazed porcelain is stronger than unglazed porcelain

cementation

• is the process attaching any part by means of a cement

• is selected according to the function and biological demands of the particular clinical situation

luting agents for temporary crown

• zinc oxide eugenol

• polycarboxylate temporary cement

• non eugenol cement

zinc oxide eugenol

• widely used biocompatible dental material for temporary crown cementation

• offering sedative

• antibacterial

• obtundent properties that soothe sensitive dentin

non eugenol cement

• used if a resin cement will be used for a final restoration as eugenol can inhibit resin curing

polycarboxylate temporary cement

• is a non eugenol water soluble cement used for

• temporary crown

• bridges

• inlays and onlays

• it is designed for easy removal and provides quality seal without irritating the pulp

for final cementation

• glass ionomer cement type 1

• resin cement

• resin modified glass ionomer

• zinc phosphate

glass ionomer cement type 1

• used for permanent cementation of crown, bridges, inlays and orthodontics bands.

resin cement

• known for high strength and excellent adhesion

• ideal for ceramic/ porcelain adhesion

resin modified glass ionomer

• combine the strength of resin with fluoride release and strong bonding

zinc phosphate

• a traditional strong cement often used for metal based bridges

CEMENTATION

1. try in and adjustment

2. isolation and drying

3. cement application

4. seating the bridge

5. setting and finishing

6. clean up

7. final check

try in and adjustments

• before permanent cementation the bridge is placed in the abutment teeth to check marginal fit contact with adjacent teeth and occlusion

isolation and drying

• the prepared abutment teeth throughly dried to ensure cements binds properly

cement aplpication

• dental cements applied inside the retainers of the bridge

• crown should be filled to have excess when inserted

seating of bridge

• bridge is seated with firm consistent pressure

• often using of orangewood stick or biting force to ensure full setting

setting and finishing

• the bridge is maintained under pressure for 8-10 minutes while cement areas

clean up

• excess cement is carefully removed from the margin and under the pontic to avoid gum irritation

final check

• the bite is checked again and the bridge is polished

checking of occlusion

• using articulating paper after cementation of fixed bridge is a critical diagnostic step to ensure the restoration integrates properly with your natural bite

• because cementation can slightly increase the contact surface area and intensity of your bite this check patients long term mechanical and biological failures

primary importance of occlusion checking

• identification of high spots

• prevention damage ( including fracture or chipping, decementation and bone and tissue stress)

• patient comfort

identification of high spots

• articulating paper pinpoints areas excessive or premature contact

prevention of damage

• unbalanced bite forces (occlusal overload) can lead to serious complication

fracture and chipping

• excessive force on porcelain or ceramic surfaces often leads to structural fails

decementation

• repeated uneven pressure can break the cement seal causing the bridge loosen or fall out

bone and tissue stress

• prolonged high occlusion can lead to periodontal damage

• accelerated bone lose around the anchor teeth

patient comfort

• even minor misalignment can cause sensitivity jaw muscle tension headache or temporomandibular joint disorder

dentist often use a two step technique

• blue paper for biting

• red for grinding movements

to differentiate how the bridge function during various jaw movements

• normal contact

• heavy contact

• bull’s eye mark

normal contact

• light consistent marking similar to those on adjacent natural teeth

heavy contact

• large dark or smear like marks often indicate a high spot that requires selective grinding/ adjustment

bull’s eye mark

• a dark ring with a clear center (a bull’s eye) is a classic sign of significant high point that must be reduced.