Fundamental of Occlusion

PFM Crown Prep #4

w/ metal occlusal surface need 1.5mm occlusal reduction, porcelain occlusal need 2.0mm occlusal reduction

finish line design choices:

1. metal collar most sealed, worst esthetically

2. all porcelain

3. disappearing metal

Finish line placement/design

1. porcelain: 90

2. disappearing metal: 120 Facial surface with porcelain 1.2 to 1.3mm reduction

Tight occlusion/heavy load do metal (white gold b/c its stronger) and porcelain.

Metal on functional aspect of tooth

Porcelain on esthetic aspect

847.016 facial butt joint

Lingual margin is a chamfer (878.014 or 878.016) + lingual functional bevel Mesial is just past contact lingually

Distal is just before contact buccally.

Margin Refinement Spruing and Investing a Wax Pattern

1. Remelt the margin place the wax pattern on freshly lubricated die. Ensure that the margin is still clearly marked with the wax pencil. Remelt the entire marginal periphery of the wax pattern through to the die. 2. Trough Formation the result is a depression/trough 1-2mm wide circumferentially.

3. Addition of Wax eliminate the trough by adding wax with a wax adder or hot beaver tail burnisher. This will slightly over contour the wax pattern at the margin. Carve the excess wax almost to the margin with Hollenbeck carver. 4. Finish carving the margin with a warm beaver tail burnisher. The warm instrument results in a combination of melting, burnishing and carving of the margins.

Margin Refinement do not approach the finish line on the die with a sharp instrument. Any sharp instrument that removes stone while the wax margins are carved will produce a casting that does not fit the prepared tooth.

Final Margin Check

1. Over waxed margins, (wax that has been carried past the finish lines), may break off when the pattern is removed from the die, resulting in a short or shy margin. It may spring back if it doesnt break and result in a casting that doesnt completely seat.

2. Short Margins. A margin not waxed completely to the indicated finish line (red line) will not provide an adequate marginal seal.

3. Ripples. Any roughness in the wax near the margin will be duplicated in the casting. These may not be removed during polishing and may result in plaque accumulation and lead to irritation and inflammation of the gingival tissues.

4. Thick Margins. Thick or rounded margins will result in poor sealing of the restoration and poor cervical contours can lead to periodontal problems. The margin of wax should come to a fine edge.

5. Open margin. Can result from any of the above problems. Attention to detail is essential. The wax pattern margins must be burnished, and melted as well as cut, to ensure a close adaptation to the die margin.

After wax pattern is completed, a wax sprue former is attached to a non-functional cusp and then surrounded with investment.

The investment material is mechanically mixed under vacuum, poured around the pattern, and allowed to set.

After the investment hardens, the sprue former and wax pattern are burned out, and the molten metal is cast into the mold cavity left by the wax.

Types of Investment Material

1. Gypsum-bonded what we use. Older type, traditionally used for conventional gold alloys

2. Phosphate-bonded for PFM crowns. Designed primarily for alloys used in the metal ceramic restorations.

3. Ethyl silica-bonded for removable partial dentures. Used principally in the casting of base metal alloy partial dentures.

Gypsum-Bonded Investments 1. Type I: used for casting of inlays or crowns. Alloy casting shrinkage compensation is accomplished mainly by thermal expansion of the investment.

2. Type II: also used for casting inlays or crowns. The major mode of compensation is by the hygroscopic expansion of the investment.

3. Type III: used in the construction of partial dentures with gold alloys.

Gypsum-Bonded Investments made of (1) gypsum (2) silica (3) modifiers

Most investments now contain alpha-hemihydrate gypsum for greater strength.

The gypsum serves as a binder to hold the other ingredients together and to provide rigidity.

The investment may contain 25%-45% of gypsum product (the rest is silicone modifiers).

Contraction and Expansion of Gypsum-bonded Investments -

Gypsum shrinks considerably after dehydration from 200 to 400C (392 to 740F). A slight expansion then occurs, to approximately 700 degrees C (1300 degrees F), and then a tremendous contraction occurs.

This contraction is most probably due to decomposition, which also contaminates the casting with the sulfides of the non-noble alloying elements, such as silver and copper.

Therefore, gypsum investments must not be heated above 1300 degrees F, to help assure proper fit and uncontaminated castings. Silica in Gypsum-bonded Investments

Silica (SiO2) is added to regulate the thermal expansion

Silica eliminates the tremendous contraction of gypsum and converts it to an expansion during heating.

The expanded investment will compensate partially or totally for the casting shrinkage of the gold alloy.

Modifiers

include boric acid and sodium chloride

Regulate the setting expansion

Regulate setting time

Prevents most of the shrinkage of gypsum when it is heated above 572 degrees F

Setting Time - initial set in a few minutes, final set up to 60 minutes. Vacu-spat for 20 seconds will allow enough working time before initial set, but you must work efficiently.

Error and oversights in wax pattern will only be perpetuated in the casting. Few minutes spent on wax patterns will save hours that might be spent correcting the casting. A casting will never be smoother than the wax pattern. Nice smooth wax pattern will give you a great casting. It will also reduce the amount of time needed to finish and polish. Smooth wax patterns reduce surface tension. Reduced surface tension decreases surface bubbles during investing.

Casting ring holds investment in place during setting and ring liner accommodates setting expansion of investment. Use a piece thats 90 mm long

Sprue former is a small diameter pin or tube of wax, plastic or metal. Attaches to wax pattern being invested while the other end attaches to base former. Sprue former must allow the molten wax to escape from the mold. It must enable the molten metal to flow into the mold with as little turbulence as possible.

The metal within the channel must remain molten slightly longer than the alloy that has filled the pattern. This will provide a reservoir to compensate for the shrinkage that occurs during solidification of the casting preventing suck-back porosity.

Wax sprue formers are preferred because they melt at the same rate as the pattern and thus allow easy escape of the molten wax.

Large-diameter sprue is recommended b/c it improves the flow or molten metal into the wax pattern so gold does not solidify in the sprue and ensures a reservoir during solidification. If turbulence is generated in the molten gold from using a sprue former that is too small or too long porosities form in the gold casting.

Blow out when gold shoots all the way through the end.

Sprue is attached to a non-functional cusp at 45 degrees, the junction b/w all three waxes must be smooth.

Ring Liner used only with gypsum-bonded investments. The resilient liner is placed along the inside of the ring to provide a buffer of pliable material against which the investment can expand to enlarge the mold.

If there is no room for expansion outward, the expansion forces will be exerted inward toward the mold, resulting in distortion of the casting.

The layer of soft material b/w the investment and the wall of the ring also permits easier removal of the investment and casting from the ring later.

Ceramic paper and cellulose paper are used, we use ceramic paper at UOP.

Casting Ring Setup adjust the wax pattern up or down to within 1/8 to 1/4 (6mm) from the end of the casting ring. This places the reservoir in the heat center of the ring. Create and internal orientation dot. Insert the long end of the sprue into the hole and orient the margins of the wax pattern 90 degrees to the orientation dot. Visualize the dot at the 12 oclock position and the margins at the 3 oclock position Debubblizer surfactant painted on patterns prior to investing, reduces surface tension. Reduces chance of air bubble forming in investment and around casting which can lead to nodules on casting.

Water bath 40 minutes in water bath at 100 degrees F. if 6 rings or more in bath already, leave ring in bath up to one hour.

Hygroscopic Expansion occurs when the freshly poured investment is immersed in water bath of 100 degrees F. may be six or eight times the normal setting expansion of a dental investment. The older the investment (in terms of shelf life), the less is its hygroscopic expansion).

Effect of time of immersion into the water bath the greatest amount of hygroscopic setting expansion is observed if the immersion takes place before the initial set. The longer the immersion of the investment in the water bath is delayed beyond the time of the initial set of the investment, the less is the hygroscopic expansion.

When an investment cools from oven temp (900 F), it shrinks to less than its original dimension.

If the investment is reheated, it expands thermally to the same maximum reached whe nit is first heated. However, in practice the investment should not be heated a second time b/c internal cracks may develop.

Fundamental of Occlusion Occlusal Disease: It is the deformation or disturbance of function of any structures within the masticatory system that are in disequilibrium with a harmonious interrelationship between the TMJs, the masticatory musculature, and the occluding surfaces of the teeth.

Centric Occlusion (CO): refers to the relationship of the mandible to the maxilla when the teeth are in maximum occlusal contact, irrespective of the position or alignment of the condyle-disk assemblies.

Five Requirements of a Stable Occlusion:

1. Stable stops on all the teeth when the condyles are in Centric Relation (CR).

Point Contacts: are on lingual cusp tips of maxillary posterior teeth, buccal cusp tips of mandibular posterior teeth, central pits or marginal ridges on posterior teeth, incisals of lower anteriors and linguals of upper anteriors.

Orientation of Force: teeth are designed to absorb heavy forces in the direction of the long axis of the tooth. Most teeth are not designed to absorb damaging lateral forces.

Ideal Bite: (1) should have point contacts of the maxillary posterior lingual cusp tips and the mandibular posterior buccal cusp tips to the central fossa or marginal ridges of opposing posterior teeth. (2) forces exerted on the posterior teeth should be directed through the long axis of the teeth. (3) Normal buccal positioning of the maxillary buccal cusps should be outside or buccal to the mandibular teeth. 2. Anterior guidance in harmony with the border movements of the Envelope of Function.

Lower teeth are guided by a gentle slanted slope of the upper lingual surfaces.

3. Disclusion (separation) of all the posterior teeth in protrusive movements by the Most Anterior teeth (Anterior Guidance). Ideally this should be the 6 front teeth, but in some cases of an open bite for example, the most anterior tooth could be a bicuspid.

Note in protrusive and lateral movements there is no contact on the posterior teeth.

4. Disclusion of all the posterior teeth on the non-working or balancing side (side where the lower teeth are moving toward the tongue).

5. Disclusion of all the posterior teeth on the working side during excursions (side where the lower teeth are moving toward the cheek). A light Lateral force can loosen a post, just as it can loosen a tooth. It can also make a tooth sensitive.

Exception to rule 5 teeth may be in group function if they are in precise harmony with anterior and condylar guidance. Note: amount of contact area in a working side movement should decrease as you move posteriorly.

Key Points all five requirements must be fulfilled or one or more signs of instability will be seen in time

Teeth could loosen, wear excessively, move out of alignment, get sore, could get cervical notching abfractions. Open contact could develop, TMJ could break down, bone loss could occur, Tori could develop.

Curve of Spee allows for the normal functional protrusive movement of the mandible.

The curve of Spee begins at eh tip of the lower cuspid and touches the buccal cusp tips of all the mandibular posterior teeth and continues to the anterior border of the ramus. An ideal curve of Spee is aligned so that a continuation of this acc would extend through the condyles.

The curvature of this arc would relate, on average, to part of a circle with a 4-inch radius. Curve of Wilson the curve of Wilson is the mediolateral curve that contacts the buccal and lingual cusp tips of each side of the arch. It results from the inward inclination of the lower posterior teeth, making the lingual cusps lower than the buccal cusps on the mandibular arch; the buccal sups are higher than the lingual cusps on the maxillary arc because of the outward inclination of the upper posterior teeth. Curve of Wilson, Impact On Chewing the lingual inclination of the lower posterior teeth positions the lingual cusps lower than the buccal cusps. This design permits easy access to the occlusal table. As the tongue lays the food on the occlusal surfaces, it is stopped from going past the chewing position by the taller buccal cusps. Importance of Tongue Manipulate food down our throat, normally occurs after mashing food against palate

Dumps food laterally on our teeth during mastication, curve of Wilson is key here. Restricted Tongue: Ankylogossia -

Restricts tongue movement, move does not get transferred to the palate, food does not get pushed on lower occlussal plane for mastication, potential digestive disorders.

Overjet vs. Overlap (bite)

Class I Occlusion has ideal overjet and overbite. Class II Malocclusion retrognathid, pushed back jaw Malocclusion.

Can be causative factor in the development of obstructive sleep apnea disorder. Potential causative factors: bottle feeding, pacifier. Class III Malocclusion sometimes called an under-bite Consequences of mal-occlusion:

Bone loss

Abfractions

Flattened Occlusion, increased force

Tore

Cracked teeth

Reasons why maxillary first bicuspids most prone for breakdown.

1. First bicuspid is usually the first tooth that hits, or guides, if there is no cuspid rise.

2. First bicuspid usually has a weak root structure

3. First bicuspid usually has a proximal concavity that also makes it a weak tooth.

4. Maxillary bone less dense than mandibular bone.

Reasons for more breakdown around maxillary second molars.1. Closest tooth to the TMJ fulcrum. Less chance for error about 1:3 ratio to anterior teeth.

2. Receives strongest force on it because of muscle position.

3. Maxillary bone less dense than mandibular bone.

Abfractions due to the stresses resulting from biomechanical loading forces exerted on the teeth (static, as in swallowing and clenching or cyclic, as in chewing) both enamel and dentin can chip or break away. This loss of tooth substance, which shall be termed Abfraction, is dependent on the magnitude, duration, direction, frequency, and location of the forces. These abfractive lesions are caused by flexure and ultimate material fatigue of susceptible teeth at locations away from the point of loading. Ideal loading on teeth lines of stress directed down to apical area.

Traumatic forces lines of stress concentrating in area of cervical region. Tooth bends of flexes around pivot area. Potential reasons for abfractions, clefts, recession:

1. fairly high pivot point

2. root solid in the bone

3. crown flexes

4. enamel rods split and fracture off

5. thinness/health of bone in the area

6. tongue can play a role (abfraction totally subgingival)

* key point abnormal lateral forces that tooth was not designed to withstand flex and eventually fracture off parts of tooth.

Flattened Occlusion root, crown, bone are all solid. Bruxing is major contributor to flat teeth. Can be from attrition of the enamel just due to wear over time, ex: chewing of coarse foods.

Tori potential reasons for tori:

1. Similar to a flattened occlusion in that the root, crown and bone are all solid.

2. There is compression ionization or some form of stimulation through the bone that causes more bone to be laid down. The bone is laid down as a support system to help prevent the teeth from rocking in the bone and causing damage.

3. Tori are most prevalent in clenchers, bruxers, worriers, nervous individuals and those who have a driver-type personality. 4. They are non-pathologic outgrowths of bone.

Fractured Teeth fractured teeth are sometimes difficult to see and crack do not always show up on radiographs. One diagnostic tool that can sometimes be used is finding one significant pocket like this around a tooth when most of the other pockets are within normal limits.

Tight Bite inclines (broader surfaces) of opposing teeth are in contact. Contacts between teeth are much broader than point contacts. This may cause flat wear facets. Can be due to discrepancy in arch width and/or teeth having incorrect angulation or slant, or missing teeth (which can cause shifting or drifting of teeth). Results in forces being directed in the wrong directions within the tooth and not in the direction of the long axis.

Ideal bite point contacts and forces directed down long axis of tooth.

Incline (flat) contacts and damaging lines of force. Heavy wear facets and tori are due to tight bite* Take Home Message -

1. proper occlusion is critical to maintaining the oral environment

2. a little high spot of heavy mark on a restoration or natural tooth could lead to long-term issues.

3. one must look at the big picture of how a single occlusal disharmony could cause a domino effect.

Casting Alloys & Casting Technique

High Heat Oven

1. Start in a cold oven inserting in hot oven may result in cracking of investment.

2. Maximum temperature should be 900 degree Fahrenheit. (each additional ring add 10 minutes to ensure burnout of wax)3. Leave casting ring in oven for 1 hour (cold oven to 900F).

4. 10 minutes extra for each additional ring.

Centrifuge Machine Procedure

1. Rotate arm 3 times around

2. lock into place with pin by pulling lever up

3. check to see that cradle and counterbalance weights are in correct place

4. forces allow flow of molten metal into the mold

Gas/Air Torch

1. Used for regular alloys only, metal-ceramic casting require gas-oxygen torch

2. turn red knob first for a gas flame

3. turn green knob (air) once flame is adequate

4. Look for reducing Flame

(Mixing zone, combustion zone, reducing zone hottest part of flame/will reduce w/ least contaminants, oxidizing zone)

Technique

1. heat up cradle/crucible

2. place silver/gold alloy in crucible

3. heat until hot and shiny resembling mercury bead, note: always use reducing flame to assure even melting.4. add flux for conventional gold alloys (not metal-ceramic alloys)

5. once melted, take ring out of oven, place in cradle (must be done right away)

6. release centrifuge arm

7. let it spin until it stops by itself

8. wait 5 minutes (wait for it to lose the red glow) then quench (quench to increase ductility of metal).* be sure to orient the ring with the orientation dot so that your margins are at 90 so that centripetal force goes towards the margins.

Noble Metals include gold, platinum, and palladium - traditionally have been the basis for inlay, crown and bridge, and metal ceramic alloys, due to their corrosion resistance in the mouth.

Silver while silver is a noble metal in the periodic table of elements, it is more relative in the mouth, and therefore is not considered to be a noble metal.

Precious Metals include gold, palladium, platinum and silver - all noble metals are precious, but not all precious metals are noble (such as silver). All are white colored except for gold, which is yellow.

Base Metals non-noble elements. (put into noble metal to increase the working characteristics of the noble metals). Influence physical properties, control of the amount and type of oxidation, or add their strengthening effects to noble metal. Such metals that are reactive with their environment are referred to as base metals. Karat refers to the parts of pure gold, parts of gold in an alloy. Ex: 24-karat gold is pure gold, while 22-karat gold is an alloy containing 22 parts pure gold w/ 2 parts other metals

Fineness fineness describes gold alloys by the number of parts per thousand of gold, with pure gold being 1000 fine. Fineness rating is 10 times the percentage gold composition (an alloy that is 75% pure gold is 750 fine). Fineness is considered a more practical rating method than karat. The terms karat and fineness are rarely used to describe the gold content of current dental alloys. However, fineness is often used to identify gold alloy solders (have to make sure that if using type two gold, must use type two solder).

Dental Alloy Types:

1. Type I (soft): small inlays can be easily burnished and subject to very slight stress (inter-coronal restorations, relatively weak and under forces of mastication become worn)

2. Type II (medium): Inlays subject to moderate stress; thick crowns, abutments, pontics, and full crown

*These are rarely used anymore due to modern direct and indirect tooth-colored filling materials.

3. Type III (hard): inlays subject to high stress; thin crowns, thin cast backings, abutments, pontics, full crowns denture bases, and short span bridges.

4. Type VI (extra hard): denture base bars and clasps, partial denture frameworks, full crowns, and long span fixed partial dentures frameworks.

Dental Alloy Types 1. Metal Ceramic hard and extra hard, porcelain-fused-to-metal crowns, short span bridges (hard types), and long-span bridges (extra hard type). These alloys vary greatly in composition. Olympia Gold is what we use, primarily gold and palladium.

2. Removable Partial Denture Alloys: removable partial denture frameworks, for the most part they are lighter in weight, stronger and less expensive. Nickel or cobalt based alloys instead of the type IV alloys.

3. Base Metal Alloys: nickel and cobalt-based alloys have vastly different physical properties and handling characteristics. Used for crowns and bridges due to low cost, however margins are much harder to finish and patients may experience allergies to nickel.

Gold precious/noble

Silver precious/strength

Copper hardness/strength

Palladium precious/hardness/noble

Platinum precious/hardness/noble

ADA classifications for dental alloys:

1. High Noble: noble metal of 60% or greater. At least 40% must be gold.

2. Noble: noble metal content of at least 25%.

3. Predominantly base: noble metal content is less than 25%.

Melting Ranges

Type III gold 1652 to 1760 F (firmilay)

Ceramo metal 2192 to 2336 F (Olympia gold)

Casting temp ranges are generally about 100-150 F degrees greater than the melting range.

Recovery of Casting

1. plunge under cold water (quench) once red glow has disappeared (~5min).

2. gypsum investment will disintegrate or breakdown

3. remove gross residue with toothbrush or discoid/cleoid

4. oxides are removed by placing in 50% hydrochloric acid (Prevox) aka pickling Casting Errors and Defects

1. large nodule due to air trapped during investment

2. multiple random nodules due to inadequate vacuum during mixing

3. black, rough casting due to breakdown of investment from excessive heat

4. short, rounded margins with sharp button due to pattern too far from end of ring or, if casting is shiny, incomplete burnout of wax

5. short, rounded margins with rounded or lumpy button due to alloy not hot enough or insufficient casting force.

6. fins due to dropped ring, rapid heating of wet or unhardened mold, or excessive casting force.

7. random porosity due to debris in wax pattern. Loose particles of investment from sharp edges.

8. shrink-spot porosity due to sprue attachment too bulky. Sprue too long or thin or button too small.

9. nodules on underside only due to prolonged vibration after pouring.

Finishing and Polishing creates smooth surfaces that are less receptive to bacterial colonization. Helps prevent tarnish and corrosion. The surface of the casting that is retrieved from the investment is too rough for the mouth. The external surface of a cemented restoration must be smooth, and it should create as nearly a perfect uninterrupted transition from restorative material to tooth as possible. A rough surface accumulates plaque that is harmful to the periodontal tissue.

The amount of plaque is directly related to the roughness of the surface.

Rough surfaces are also uncomfortable to the patient.

Finishing taking a surface with deep scratches and reducing them to finer scratches that are almost undetectable to the naked eye.

Polish acquiring a smooth, shiny, lustrous surface layer.

The Beilby Layer as a gold surface is polished, minute amounts of the abraded surface material (possibly even of molecular size) are filled into surface irregularities, resulting in a microcrystalline surface layer that is known as the Beilby layer. Tarnish surface discoloration on a metal or even a slight loss or alteration of the surface finish or luster.

In the mouth, tarnish occurs from formation of calculus and plaque.

It is the forerunner of corrosion.

Corrosion actual deterioration of a metal by reacting with its environment. May occur through action of moisture, acid, or alkaline solutions and certain chemicals

Ingredients in foods and the water, oxygen and chloride present in saliva all contribute to corrosion.

Use of Abrasives

Abrasive are exceptionally hard materials that develop sharp cutting edges when they are chipped.

Polishing materials consist of abrasives and softer material that are reduced to extremely fine particle size.

For maximum cutting efficiency, the abrasive must be appreciably harder than the material on which it is used.

Finishing and polishing should start with an abrasive that is coarse enough to remove gross irregularities.

The surface is smoothed with abrasives of progressively smaller particle size.

This way scratches are substituted with increasingly smaller scratches until they are eliminated or reduced to microscopic size.

Diamond the hardest of all abrasives, diamond should be reserved for use on hard, brittle substances such as enamel or porcelain.

Silicon Carbide pressed into may shapes to form separating discs and the many points and wheels known as green stones.

Aluminum Oxide a course grit is used in the brown, pink, or coral stones used for finishing metal ceramic copings. A fine grit is used in white stones, which may also be used on gold.

Sand sandpaper disks are coated with a dense crystalline form of quartz, called flint. Flint is a naturally occurring mineral that chips to form sharp cutting edges. It is not as durable of strong as some other abrasives, but it is a useful abrasive in finishing cast gold.

Impregnated rubber wheels, discs and points used for polishing metals and ceramics. Available in various grits.

BBC (buffing bar compound) a fine polishing powder combined with a wax binder to form a black cake. Used in the initial polishing step of gold on either a bristle brush or a cloth buff wheel.

Rouge composed of iron oxide (Fe2O3), also in cake form. Used in the final step of polishing gold castings. It is applied with a soft bristle brush or a buff wheel. Forms of Abrasives these materials are bonded to a paper backing or mixed with a binder and pressed into various shapes. They come in the form of stone or rubber wheels, discs, and points that are used for specific processes. They are also incorporated into pastes for use on brushes, cloth wheels, or rubber cups.

1. Separating discs (joe dandy discs) stiff discs that cut on the edges as well as on the sides. Useful for removing sprues from castings, for sectioning fixed partial dentures, and for contouring embrasures around pontics. 2. Moores Discs flexible paper discs coated on one side with various grits or garnet, sand, emery, and cuttle, and are used for contouring and smoothing large convex areas on gold. Each disc has a square hole for mounting on a special mandrel, which allows them to be rotated in reverse.

3. Heatless Stones (Mizzy Stones) extremely coarse stones for bulk removal of metal (not necessarily heatless!)

4. Busch Silent Stones large, fine-grained stones for reducing broad areas of porcelain.

5. Green Stones contain silicon carbide. Manufactured in may different shapes. Permanently mounted to their mandrels, so they can be rotated in reverse as well as forward.

6. White Stones contain fine-grained aluminum oxide. Useful for smoothing the rough surfaces left by green stones and for adapting gold margins to enamel intraorally

7. Rubber wheels, Discs, and Points for finishing and polishing metals and ceramics. Course discs, finer discs (Burlew), even finer discs (Brownies and Greenies).

When using abrasives use higher speed and light pressure, higher pressure produces more heat. Especially with finishing, move the disc about quickly to avoid the formation of flat spots (light pressure helps too).

When making an adjustment during the finishing process, care should be taken to reshape the anatomy, rather than creating dents and facets in order to smooth out the adjustment.

Wheels are good for adjusting contact areas.

Discs are good for broad surfaces, such as axial surfaces of a crown.

Points are good for getting into the grooves.

Clinical C.I.M.O.E.

1. Contacts: probably tight due to application of porcelain maintain proper position and shape

2. Internal: use fit-checker to locate premature internal contacts

3. Margins: make sure closed to 25 micro tolerance use pig-tail explorer

(open, over-contoured, under-contoured)

4. Occlusion: check patient in both centric and lateral positions adjust as needed

5. Esthetics

Use horizontal depressions to make crown appear wider (round diamond burr)

Move line angles to lateral borders to aid in widening crown

Use facial depressions to make crown appear less flatter and narrower

Cast Refinement

Greatest benefit: decrease chair time for pre-cementation adjustment of occlusion

Die Trimming: to have access to the margin

Goal of Mounted Casts: M.I. of mounted casts should be identical to M.I. of teeth

Steps to Process:

1. Remove positive errors

2. Secure casts in maximum intercuspation (glue gun)

3. Mount casts in M.I.

4. Position two pieces of mylar marking media (accufilm) to cover entire arch and tap in M.I.

5. Eliminate all M.I. incline contact (posterior teeth)

6. Continue mark and adjust cycle until M.I. refinement objectives are met

7. Eliminate all excursive incline contacts that prevent contact of desired existing wear facets.

8. RL, LL, and P excursions completed

Do not adjust marginal ridges of teeth adjacent to preparations!

Do not alter tooth contours of teeth opposing preparations!Concepts in Bridge Preparation Always think of bridge prep as a single tooth.

As length increases it is more difficult to judge draw. Criteria for the preparation

1. Each individual abutment preparation must have individual draw

2. Each abutment preparation must draw with each other

3. The preparations should be centered along the long axis of the tooth/teeth (think of FPD as one unit)

4. The finish line is positioned .5mm supragingival lingually, and .5mm subgingivally on facial.

5. A chamfer finish line is used lingually, a shoulder facially

6. the total occlusal reduction is 1.5mm on all cusps

7. the cusps should be centered along the arch form

8. cusp inclines should not be modified

9. 6-10 degrees of taper should be maintained

10. Chamfer-shoulder blend must occur just lingual to the proximal contact points.

Want to establish draw as one unit, four walls with converging draw Review treatment plan (several questions should be asked):

1. Is the design of the FPD Ive chosen to use the vest alternative?

2. Should I have considered a RPD or implant?

3. What is the individual crown to root ratio of each proposed abutment tooth? Bare minimum is crown to root ratio of 1:1, ideally would like to try to have 2:3.4. What is the root configuration of each abutment tooth? Teeth that have concavities in their roots are better support, oval roots (canines) are little support for fixed pros.

5. Will Antes Law be violated? Antes Law the peri-cemental coverage of 2 abutment teeth need to be greater than the peri-cemental coverage of the tooth being replaced. (peri-cemental root surface area of tooth).

6. Are the individual abutments sound?

7. Are they strong enough to withstand the patients occlusal forces?

8. How will I restore the occlusion? (need to consider curve of Wilson and curve of Spee.)

9. Are there other teeth that need addressing prior to FPD preparation?

10. Am I ready for the preparation appointment? (may have considerations other than just the bridge/abutments.)

Prior to the preparation appointment several questions must be asked:1. Have any medical concerns been addressed?2. Are all teeth periodontally stable?

3. Have caries been arrested?

4. Is the oral hygiene of the patient acceptable? (important)

5. Have financial arrangements been made?

6. Do I have mounted study models?

7. Do I have pressed form splint or putty matrix fabricated?

8. Is my diagnostic wax-up completed?

9. Have I completed the provisional shell?

10. Have I determined the abutment design?

11. have I a clear goal what must be accomplished at the first appointment? Retainer Designs there are many options and combinations to select from:

1. range from conservative to heavily prepared

2. most conservative = Maryland bridge retainer

3. least conservative = porcelain jacket retainer

4. other retainers options included inlay, onlay, FVC, PFM

5. a combination of these could be considered.

Restoration Design all completed before you ever touch the patient

1. what material will be used?

2. what material will the patient occlude against?

3. what type of connector will be used?

4. what will be the shape of the pontic?

5. where will the margins be located? (complete the laboratory Rx propr to tooth preparation)

Post and Core options Restorations of Endodontically Treated Teeth

Various Options: endodontically treated, alloy w/ or w/out plugs, comp w/ or w/o plugs various types of resin, direct post and core, indirect custom cast post and core, non endodontically treated, alloy, composite light polymerized or auto polymerized.

Deciding what to use: vital vs. non vitalComposits for smaller cores, amalgams for larger cores. Dowel Overview The longer a dowel, the greater its retention. A tooth with a dowel that is the length of the crown or shorter has less chance for success than a tooth that has no dowel at all.

The success rate of dowel-treated teeth can increase to more than 97.5% when dowel length equals or exceeds the length of the crown.

Despite innovative designs...the amount of remaining dentin and root morphology may be the ultimate factors in resistance to fracture.

94% success teeth with coverage, 56% success teeth without coverage.

Fractured tooth #10 what steps are taken prior to restoration?

1. Assess amount of remaining tooth structure, is there enough biological width? Must have 1.0 to 2.0mm of vertical axial tooth structure. This creates a ferrule effect.

Ferrule Effect should be created using remaining tooth structure prior to pattern fabrication.

1. 1.5mm 2mm long

2. parallel walls

3. totally encircle tooth

4. end on sound tooth structure

5. not invade attachment apparatus

2. Cast Dowel Pattern fabricated with acrylic resin or composite resin. Dowels should extend at least the length of the crown or 2/3 the length of the root which ever one is greater. Dowell Length dowels should be at least the length of the crown or 2/3 the length of the root which ever is greater except when the root is curved or dilacerated. Then the post length must terminate at the point at which the curve or dilacerations begins (if you dont stop here, you will go right out the side of the tooth). This ensures that the tooth is not subject to pre-mature fracture and increases the retention of the post. Shoulder Preparation the apical endodontic fill should be 4.0mm (want to maintain a gutta percha seal of at least 4mm.

Custom Cast Dowel and Core the indirect method is accomplished in 3 steps:

1. Step one: canal preparation cannot violate biological space, need 3mm from crest of bone to tooth for biological width. 2. Step two: pattern fabrication Duralay, (1) create the shape of original tooth (2) then do ideal crown preparation on duralay model. 3. Step three: finishing and cementation 1.00 2.00 mm below the margin of your core. Crown Fabrication the finished crown should create a ferrule effect. The ferrule effect requires 1.0 to 2.0mm of tooth structure below dowel. Ferrule Effect: the action of surrounding an object with a ring. In this case a crown. (ex: putting a metal band around a piece of wood and then trying to chop it, not going to fracture in half as easily). Precision Attachment RPD adds additional stress to already compromised situation.

Natural tooth post and core dowels are only made to retain a core, they do nothing to strengthen the tooth, rather they weaken it.

The dowel provides retention for the core and the coronal restoration

Protects tooth by dissipating or distributing forces along the length of root

Does not strengthen a tooth. It weakens a tooth if dentin is sacrificed by placing a large diameter dowel.

Natural tooth post and core a tooth with an intact clinical crown can be adequately restored with composite resin. A dowel provides unnecessary reinforcement that may weaken the tooth.

A dowel diameter should be no more than one third the root diameter at the CEJ. As you move more apically no less than 1 mm at midroot and beyond. Dowel Shape active vs. passive, taper (morphologic) vs. parallel

Active actively engages dentin of tooth (dont like so much b/c add unnecessary lateral forces in the tooth, may lead to fracture.)

Parallel Sided & Passive very nice, no lateral forces and still retentive.

1. Consider preformed posts in roots with large cross-sectional diameters: Maxillary incisors

Maxillary canines

Maxillary molars palatal root

2. Consider morphologic cast posts in narrow ribbon shaped roots:

Mandibular incisors

Maxillary premolars

Mandibular molar distal roots

Morphologic cast Posts more conical shape and as such have the potential to act as wedge if not placed properly. Less retentive than parallel-sided posts in large root diameters

Minimal stress during cementation

Act as wedges during occlusal loading in short lengths

Clinically in large teeth with morphologic features: Resin reinforcement significantly improves the structural resistance to facture of thin walled teeth compared to morphologic dowel restorations.

Intracanal anatomy may nave been destroyed during endodontic access*

Pathology may create large intracanal irregularities

Consider Luminex System internally etch interior of canal and bond composit, can be used to fix anatomical abnormalities.

Ability of posts to resist forces:

1. increased length

2. parallel sides

3. moderate diameter

Ideal post diameter should not exceed 1/3 diameter of the tooth.

Standard parameter for dowel length

1. two-thirds of the length of the canal.

2. equal coronal and radicular lengths (1:1 root to crown ratio, enable the forces to be distributed along the long axis of the tooth more easily.)

3. one-half the bone supported length of the root.

4. preservation of endodontic seal 3-5mm, 4mm ideal.

Inadequate dowel length increases risk of tooth fracture. Must be below crest of bone.

Too much taper can cause fracture when vertical forces are applied.

Violation of post size increases risk of fracture due to large size of cast post and core, can split the root in many directions. As post diameter increases, resistance to root fracture is directly related to remaining tooth structure.

Ideal Dowel 3mm from a fixed prosth. Point of view. 7mm from an endodontic point of view. 4 mm happy midpoint.

Preparation 1. Part one- canal preparation: prepare tooth using conventional anterior PFM design creating a ferrule effect. Remove any unsupported coronal tooth structure so that the height is no greater than twice the width. Then place an anti rotational groove.

The height of can be no greater than twice the width of crown

Counteract rotational forces, into side of post hole prep, locking feature

2. Para post kit: (extremely aggressive cutting instruments) for build-up and cast dowel fabrication. Various sizes: never being with desired end size to save time. Always step up from smallest to desired end size. Burn out posts correspond to drill size in para post kit, and are available at clinic window.

Have two main functions

1. For pre-fabricated dowel and core use

2. To retain provisional

3. Initial gutta percha and tooth structure removed with : (1) warm lux plugger (2) gate glidden burs or peeso. These are not end cutting burrs, just cut on sides to remove gutta percha.

4. Try in steal post, this will be used later in provisional fabrication. Confirm working length with radiograph.

5. Use salt and pepper technique w/ Duralay.

Remove gutta percha

Size canal appropriately with para post drill

Lubricate canal with Vaseline

Bead and flow additional duralay around burn out post

Pomp as needed

Confirm passive fit upon final set

Place back into canal

Build coronal portion of cast post with salt and pepper technique.6. Select desired post size and mark working length with rubber stopper on instrument.

7. Confirm working length

8. Pattern fabrication dappen dishes are used to aid application of duralay to the plastic post. Initial placement of post and acrylic place post in canal before initial shine is lost. Building the pattern: after initial set remove pattern and confirm accuracy, replace and allow for full set. Using s&p technique to build pattern in steps. After complete set, the material will withstand indentation with the explorer and possess no shine.

9. Re-prepare tooth after set using the criteria for an anterior PFM crown prep, prepare tooth.

10. After complete set and preparation refinement, remove pattern and check for detail. Pattern can be added to if any voids are present.

11. At this point the pattern shipped to lab for investment and casting.

Clearfil Photocore in non-endodontically treated teeth, light cured composit resin only.

Paracore bonded resin, dual cured.

Core paste not used, bad.

BondLink bond enhancer. Simply a coupling agent that bonds between single bottle adhesives and self cure composites.Treatment planning for the replacement of missing teeth Missing teeth can be replaced by one of three prosthesis types:

1. removable partial denture (RPD)

2. tooth-supported fixed partial denture (FPD)

3. implant-supported fixed partial denture

selection of the type of prosthesis several factors must be considered when choosing the type of prosthesis:

1. biomechanical

2. periodontal

3. aesthetic

4. financial factors

5. patients wishes

the general dentist or prosthodontist will act as the quarterback and should manage the sequencing and referral to other specialists. The treatment guidelines we recommend are just guidelines, not laws and are not absolute.

Removable Partial Denture (RPD) indications:

1. edentulous space greater than two posterior teeth (in line with Antes Law)

2. anterior space greater than four incisors

3. spaces that include a canine and two other contiguous teeth

central incisor, lateral incisor, canine

lateral incisor, canine, first premolar

canine and both premolars

an edentulous space with no distal abutment will usually require a RPD

there are exceptions where cantilever FPDs can be considered, but approach cautiously

requirements for abutments for a RPD are not as stringent as those for FPD (not as important b/c have a large framework that are distributing forces throughout the mouth).

Conventional tooth-supported FPD when a missing tooth or teeth are to be replaced, a FPD are preferred by the majority of patients

If the abutment tooth are periodontically sound, the edentulous space is short and straight, and the retainers are well designed and executed, the FPD can be expected to provide a long life of function.

There should be no great soft tissue defect (if present, ridge augmentation may be required)

A dry mouth creates a poor environment for a FPD

Tooth position and alignment are maintained, in part, by the interaction b/w teeth

When a tooth is removed, adjacent teeth often migrate into the vacated space

If a FPD is fabricated without first re-establishing the occlusal plane, an occasional interference may be created (this is confirmative dentistry, need to make condition better than when patient comes in. This could potentially lead to lateral interferences.)

Occlusion is properly restored by correction of the occlusal plane in conjunction with placement of FPD (crown on 14 first, then the FPD in order for thickness of gold to be maintained - this may mean root canal for 14). Components of FPD:

Resin-bonded tooth-supported FPD

Conservative restoration

Reserved for the use on defect-free abutments

Generally used to replace a single missing tooth (usually an incisor or premolar)

Should not be used with a deep vertical overlap because possibility of fracture is greatly increased (metal to tooth bond is never that great) Preparations require resistance features (well-defined grooves)

Implant supported FPD

Ideally suited for use where there are insufficient numbers of abutment teeth or inadequate strength in the abutments to support a conventional FPD

Implants can be used as a pier, but there is some risk involved in using this with natural teeth

In a dry mouth implants can survive better than natural teeth.

No prosthetic treatment

If a patient presents with long-standing edentulous space into which there has been little or no drifting or elongation of the adjacent or opposing teeth, the question of replacement should be left to the patients wishes.

This does not contradict the recommendation that missing teeth routinely should be replaced. Doesnt affect the patients lifestyle, function is fine

Abutment evaluation Whenever possible an abutment should be a vital tooth (theyre always going to be better abutments) Endodotically treated teeth can be used as abutments (weaker abutment and may need to consider including an additional abutment with endodontically treated abutment.) Teeth that have been pulp capped should not be used as abutments (rule a school). If a tooth has been pulp capped proceed w/ endodontic treatment. (delivering a new bridge and then having to proceed with endo sucks, b/c then you have to drill a hole through it.) The supporting tissues surrounding the abutment teeth must be healthy and free from inflammation before any prosthesis can be contemplated.

The roots and their supporting tissues should be evaluated for three factors:

1. crown-root ratio

2. root configuration

3. periodontal ligament area

Crown-Root ratio a measure of the length of tooth occlusal to the alveolar bone compared to the length of the root embedded in the bone.

With apical movement of the bone, the chances of harmful lateral forces increases.

The optimum crown-root ratio for FPD is 2:3, ratio of 1:1 is minimum that is acceptable.

There are situations in which crown-root ratio greater than 1:1 might be considered adequate (ie the root is shorter than the crown)

Ex: if the occlusion opposing a proposed FPD is composed of artificial teeth, occlusal forces will be diminished, with less stress to the abutment teeth.

Root Configuration - conical incisor bad, three rooted molar good

Important point in the assessment of an abutments suitability from a periodontal standpoint.

Roots that are broader labiolingually than they are mesiodistally are preferable to roots that are round in cross section (incisors).

Multirooted posterior teeth with widely separated roots will offer better periodontal support than roots that converge. Although the root surface area of teeth may be similar, the root configuration of the max premolar with greater faciolingual dimension, makes it a superior abutment to the central incisor.

The molar with a divergent root will be better than abutment tooth tan one whose roots are fused.

Periodontal Ligament Area

1. large teeth have greater surface area and are better suited to withstand added stress

2. When supporting bone has been lost due to periodontal disease, the involved teeth have a lessened capacity to serve as abutment.

3. The length of the pontic span that can be successfully restored is limited, in part, by the abutment teeth and their ability to accept additional load.

Antes Law

Stated that the root surface area of the abutment teeth had to equal or surpass that of the teeth being replaced

If two teeth are missing, a FPD probably can replace the missing teeth but the limits are being approached (ex: with anterior teeth, where the occlusal loads are not as great as in the posterior of the mouth)

It is possible for FPDs to replace more than two teeth The most common example is an anterior FPD replacing four incisors

Canine to second molars are also possible.1. The combined root surface area of the second premolar and the second molar is greater than that of the first molar being replaced.

2. The combined root surface area of the first premolar and the second molar abutments is approximately equal to that of the teeth being replaced.

3. the combined root surface area of the canine and the second molar abutments is exceeded by that of the teeth being replaced.

Biomechanical considerations

there is one unit of deflection(X) (how much flexure in a pontic bridge that may occur) for a given span length (p)

The deflection will be 8 times as great (8X) if the span length is doubled (2p)

The deflection is 27 times as great (27X) when the span length is tripled (3p)

There is one unit of deflection (X) for a span with a given thickness (t)

Connector spaces there will 8 times as much deflection (8X) if the thickness is decreased by one-half (t/2).

Problem with flexure is that it may cause fracture in the porcelain.

FPDs are usually made with white gold (type IV stronger than normal gold b/c its had other metals added to it).

Tilted molar abutments when a mandibular molar tilts mesially, there is a discrepancy between the long axis of the molar and that of the premolar.

One treatment option is the use of ortho

FPD using a proximal half crown as a retainer on a tilted molar abutment

FPD using a telescope crown and coping as a retainer on a tilted molar abutment.

A nonrigid connector on the distal aspect of the premolar retainer compensates for the inclination of the tilted molar.

Mo inlay preparation conservative prep as the retainer.

Indirect Provisional Restorations Steps taken prior to preparation:

1. review of health history

2. review of dental history

3. full mouth series of x-rays

4. treatment planning patient involved

5. financial arrangements

6. study models face bow transfer

7. mounting study models

8. diagnostic wax-up and model fabrication

9. pressed from splint fabrication

10. indirect provisional fabrication

11. preparation design

12. build-up fabrication

Pressed form splint fabrication:

Using the mounted diagnostic cast fabricate pressed form splint.

This is accomplished by placing false teeth in the edentulous space.

Template-fabricated provisional FPD

When a FPD is to be made, the provisional restoration should also be in the form of a FPD

In the posterior this method will better stabilize the teeth than individual crowns

Patient can become accustomed to having a tooth or teeth in the edentulous space

Pressed form splint fabrication once the cervical areas of the false teeth and edentulous spaces have been blocked with small bead of wax, an impression is made of the quadrant. This impression may be poured in a fast setting stone (mounting stone or yellow stone with slurry water added.)

Template-fabricated provisional FPD

1. crown forms or denture teeth are placed in the edentulous space on the diagnostic cast.2. if the cast is relatively thick, a hole can be drilled though the center for better adaptation of the pressed form splint

3. a plastic sheet is secured in the frame of the vacuum forming machine

4. the plastic sags as it is heated to the proper temp. allow to sag below lower rim of plastic retainer (@ least 1 inch).

5. pull frame down over the perforated stage of he vacuum forming machniie and engage vacuum

6. cut plastic to remove the template from the diagnostic cast.

7. cut out pressed from splint two teeth distal and mesial to the abutment teeth. For a six-unit bridge there should be ten teeth in pressed from splint. 8. prepare quadrant arch or duplicate impression for FPD. Note: preps should be more conservative than those planned for final restoration.9. try template on quadrant arch impression and confirm fit. Coat all teeth with petroleum jelly.10. mix acrylic resin (bosworths trim) and fill splint in area of the bridge.11. place some acrylic in the interproximal areas of the cast12. fully seat splint and hold in position with rubber bands, rubber bands should be in places where theyre supported by natural teeth13. the provisional (any methyl methacrylate) and quadrant arch assembly are placed in your Aqua-press for 10-15 minutes with warm water at 15 PSIs. note: fill press to top and tighten at the sink.excess water will escape. 14. remove provisional from the cast. The model may have to sacrificed. Once the provisional shell is removed from the cast it is grossly trimmed15. trim provisional to create ovate pontics with properly formed embrasures16. smooth pontic area. Provisional shell is now ready for preparation appointment. Laboratory Fabricated Provisional FPD good for long-span provisionals or long-span posterior provisionals that are exposed to greater forces. These are also useful in cutting down chair time in large reconstructive cases. Cements and Cast Post and Core Cementation1. examine surface under magnification for obvious surface irregularities

2. remove surface irregularities

3. place fit checker on post

4. try-in with minimal apical pressure

5. allow to cure remove prematurities

6. repeat process until complete setting

Cement Selection there are several types of cements available for the permanent retention of indirect restorations

Types

1. zinc phosphate

2. zinc silicophosphate

3. polycarboxylate

4. glass ionomer

5. composite resin cements

6. hybrid ionomer cements

Definitive Cement Properties

Thin film thickness

Low solubility

High compressive strength

Retentive/bonding properties

Biocompatible

Ease of use

Pacific Cements permanent cements

1. zinc phosphate cement

2. reinforced glass ionomer

auto mixed

hand mixed

3. self-etch adhesive resin cement

Polycarboxylate Cement

Higher tensile strength than zinc phosphate

Significantly lower compressive strength than zinc phosphate

Low pH (4.8)

Little effect on pulp due to size of molecule

Bonds to enamel, dentin and stainless steel but not gold

Brand names: durelon, carbosylon

Made of:

Liquid: polyacrylic acid

Powder: zinc oxide

Glass Ionomer Cement

Has many properties of an ideal cement

Has a 10-60% fluoride content in its powder

In use since 1977 in US

Hass good compressive and tensile strength

Tin-plating can cause bond to restoration

Less soluble than zinc phosphate

Studies show that G.I. are more retentive than zinc phosphate

Brand names: Advance, Fuji Duet

Not without disadvantages:

pH is lower than zinc phosphate

if exposed to moisture during cementation greatly reduces strength

micro expansion = increased root fracture potential following post cementation

GC Fuji Plus (were using to cement the gold crown).1. lightly hand shake material to loosen contents

2. activate by compressing pink plunger at base completely

3. mix in amalgamator for 8 seconds

4. load crown immediately and seat on dry (not desiccated) preparation

GC FujiDem hand mixed original version of Fuji Plus. Same chemical component as Fuji Plus. Express by clicking activator until desired quantity is present.

Zinc Silicophosphate Cement

Has high compressive strength

Moderate tensile strength

Acidic pH Problem: thick film thickness, can prevent complete seating of restoration

Not used much anymore

Zinc Phosphate Cement

Possesses high compressive strength

pH of 3.5 at time of cementation

has been blamed for contributing to pulpal irritation

used at UOP in limited situations

easy to clean and remove excess

brand names: flecks, lee smith zinc

made of:

1. Liquid orthophosphoric acid

2. Powder zinc oxide

Cementation with Zinc Phosphate Cement Field must be kept dry during final placement

Quadrant is isolated with cotton rolls and suction

Can place copal varnish, or dentin bonding agent to reduce pulpal irritation

Cool glass slab is used with one cap full of powder and 5-6 drops of liquid. Small increments of powder are introduced into the liquid. Always incorporate powder to liquid. Cement is mixed with a circular motion over a wide area.

Test the cement by lifting the spatula about an inch off the glass slab; cement should string out roughly one inch.

The inner walls of the crown are coated with a thin layer of cement, using the small end of an instrument or brush.

While the cement hardens, the patient maintains pressure by biting on a resilient plastic wafer or wooden stick.

Immediately after placement of restoration in patients mouth clean glass slab under running water. Failure to do this will allow cement to harden on your glass slab and make cleanup quite difficult.

Resin Luting Cement

Composed of a resin matrix of bis-GMA and a filler of fine inorganic particles

Can be light-cured , autopolymerizing, or dual cured

Poor technique = potential for leaking due to setting shrinkage or poor dentinal bond

New cements do not require dentin bond material to prevent pulpal reactions.

Usually in a paste-paste form

Brand names: rely-x, all-bond, C + B metabond, EnForce, Panavia 21, and many others.

RelyX Unicem: self-adhesive resin cement (were using to cement the P2Z and cast post). Activation for 5 seconds

Trituration 15 seconds

Dispensing: 30 seconds working time

Pacific Cements

Provisional cements

1. Temp Bond

2. Ultra Temp Polycarboxylate

3. Temp Bond NE

Polycarboxylate Cement

Higher tensile strength than zinc phosphate

Significantly lower compressive strength than zinc phosphate

Low pH (4.8)

Little effect on pulp due to size of molecule

Bonds to enamel, dentin and stainless steel but not gold

Brand names: durelon, carboxylon

Made of:

Liquid: polyacrylic acid

Powder: zinc oxide

Directions for use

1. switch cap with mixing tip

2. dispense directly into clean provisional restoration

3. seat provisional on dry tooth

4. clean off excess with damp 2x2 or wet microbrush

Temp Bond NE Kerr: NE = non-eugenol

Should be used as a replacement for eugenol containing provisional cements when either a resin cement or reinforced glass ionomer cement is to be used as the definitive cement.