Restoration Of Endodontically Treated Teeth

Restoration of Endodontically Treated Teeth

Contents • • • • • • • • • •

Introduction Historical development General Considerations Tooth preparation Techniques for post fabrication Core build up Removal of existing Posts Recent advances in posts Conclusion Bibliography

Restorations of endodontically treated teeth are designed to protect the remaining tooth from fracture and to replace the missing tooth structure

The final restoration may include some combination of Dowel Core Coronal restoration

Dowel /Post ,extensively rigid restorative material placed in the root of a non vital tooth The dowel provides retention for the core and must be designed to minimize the potential for root fracture from functional forces.

The Core replaces lost coronal tooth structure and provides retention for the crown. The Crown restores function and esthetics and protects the remaining root and coronal tooth structure from fracture.

Historical Development Various methods of restoring pulpless teeth have been reported for more than 200 years. In 1747, Pierre Fauchard described the process by which roots of maxillary anterior teeth were used for the restoration of single teeth and the replacement of multiple teeth.

Posts were fabricated of gold or silver and held in the root canal space with a heat softened adhesive call “Mastic”.  The longevity of restorations made using this technique was attested to by Fauchard:

Teeth and artificial dentures, fastened with posts and gold wire, hold better than all others.

They sometimes last fifteen to twenty years and even more without displacement. Common thread and silk, used ordinarily to attach all kinds of teeth or artificial pieces, do

In Fauchard’s day, replacement crowns were made from bone, ivory, animal teeth, and sound natural tooth crowns. Gradually, the use of these natural substances declined, to be slowly replaced by porcelain.

A Pivot (what is today termed a Post) was used to retain the artificial porcelain crown into a root canal, and the crown-post combination was termed a “Pivot Crown”. Porcelain pivot crowns were described in the early 1800s by a well-known dentist of Paris, Dubois de Chemant.

Pivoting (posting) of artificial crowns to natural roots became the most common method of replace artificial teeth and was reported as the “best that can be employed by Chapin Harris in the Dental Art in 1839.

Early pivot crowns in the United States used seasoned wood (white hickory) pivots. The pivot was adapted to the inside of an all-ceramic crown and also into the root canal space.  Moisture would swell the wood ,giving it a tighter fit and helped retain the pivot in place.

G.V.Black later developed a porcelain faced crown secured in place with a screw embedded in gold foil filling the canal The Richmond crown was in vogue for many years which is a self contained restoration with dowel being a part of the final crown

Prothero reported removing two central incisor crowns with wooden pivots that had been successfully used for 18 years. Subsequently, pivot crowns were fabricated using wood/metal combinations, and then more durable allmetal pivots were used.

Metal pivot retention was achieved by various means such as threads, pins, surface roughening, and split designs that provided mechanical springs retention

Unfortunately, adequate cements were not available to these early practitioners cements that would have enhanced post retention and decreased abrasion of root caused by movement of metal posts within the canal.

One of the best representations of a pivoted tooth appears in Dental Physiology and Surgery, written by Sir John Tomes in 1849. Tomes’s post length and diameter conform closely to today’s principles in fabricating posts.

Endodontic therapy by these dental pioneers embraced only minimal efforts to clean, shape, and obturate the canal. Frequent use of the wood posts in empty canals led to repeated episodes of swelling and pain. Wood posts, however, did allow the escape of the socalled “Morbid Humors”.

Although many of the restorative techniques used today had their inception in the 1800s and early 1900s, proper Endodontic treatment was neglected until years later.

Structure of endodontically treated teeth • Papa and others found no significant difference in the moisture content between endodontically treated teeth and vital teeth • Vital dentin exhibited a moisture content of 12.35 % whereas dentin from endodontically treated teeth had a moisture content of 12.10%

• Huang et al compared the mechanical properties of human dentin from treated teeth and vital teeth and noted an insignificant effect of Endodontic treatment on compressive and tensile strength of dentin • The volume of tooth loss is perhaps the primary factor in the decreased strength of endodontically treated teeth

FEW IMPORTANT QUESTIONS…

SHOULD CROWN’S BE PLACED ON ENDODONTICALLY TREATED TEETH? Retrospective study of 1,273 teeth endodontically treated 1-25 years previously compared the clinical success of anterior and posterior teeth.

• It was determined that coronal coverage did “NOT” significantly improve the success of endodontically treated ANTERIOR teeth.

Crowns are indicated only on those endodontically treated anterior teeth when they are • Structurally weakened by large restorations • Multiple coronal restorations • Color changes that cannot be effected by bleaching, resin bonding and porcelain laminate veneer

Significant increase in clinical success was noted when cuspal coverage crowns were placed on maxillary and mandibular premolars and molar. Restorations that encompass the cusps ,that have interdigiation with opposing tooth

Conclusion 1.Crowns should be placed on endodontically treated POSTERIOR teeth that have occlusal interdigitation with opposing teeth ( wedging) 2.Crowns DO NOT enhance the clinical success of ANTERIOR endodontically treated teeth.

WITH PULPLESS TEETH, DO POSTS IMPROVE LONG-TERM CLINICAL PROGNOSIS OR ENHANCE STRENGTH? • Lovdahl and Nicholls ( 1977), Lu (1987) and others – posts and core FAILS to increase the fracture resistance or decrease the fracture resistance of endodontically treated teeth.

• Hunter et al (1989) in a photoelastic stress analysis • If walls of a root canal are thin owing to removal of internal root caries or over instrumentation during post preparation,increases stress – post “may” STRENGTHEN THE TOOTH.

Kocc et al (1992) FEA study a.When loaded Vertically along long axis – post decreases maximal dentin stress by 20% b.450 angle loading – 3 to 8 % decreases in stress The reinforcement effects of posts is doubtful for anterior teeth because they are subjected to angular forces

• Eckerbom etal (1991):examined radiographs of 200 patients and reexamined them after 5 yrs and concluded that “Apical periodontitis was significantly more common in teeth with posts than endodontically treated without posts.”

CONCLUSION:

Purpose of a post is to provide “RETENTION” for a core.

WHAT IS THE CLINICAL FAILURE RATE OF POSTS AND CORE? Answer: Post and core – average absolute rate of failure 9 % (7 to 14 % range)

WHAT ARE THE MOST COMMON TYPES OF POST AND CORE FAILURE ? Answer : Loss of retention,post loosening and root fracture are the most common causes of post and core failure.

• WHICH POST PRODUCES THE RETENTION?

DESIGN GREATEST

CLASSIFICATION 1. Custom made 2. Prefabricated Mode of retention

1. Active:primarily gain retention by threads that engage the intraradicular tooth structure 2. Passive:gain their retention

Depending on the material used 1.Metal(stainless steel,platinumgoldpalladium,titanium) 2. Carbon fiber 3. Fiber Reinforced Composite 4. Ceramic 5. Thermoplastic

Depending on shape Parallel Tapered Depending on surface Smooth Serrated Threaded

• Tapered , Smooth-sided Post System • Tapered ,Serrated post system • Tapered , Threaded Post System • Parallel ,Smooth- Sided Post System • Parallel –Sided , serrated Post System • Parallel –Sided , threaded Post System

• These broad categories are no longer useful because of continued development in the field. • Dowels exhibit features of more than one category ,therefore classification by desired clinical properties is more clinically meaningful.

Three clinically significant features can be categorized as follows • Retentive qualities of dowels • Protective qualities of dowels • Esthetic qualities of dowels

Tapered post has a wedging effect that creates stress on the root Tapered Posts are the least retentive and threaded posts the most retentive .

Parallel posts resist tensile , shear and torquing forces better than tapered posts It distributes stress more evenly along their length during function,providing greater protection against dentin failure.

• IS THERE A RELATIONSHIP BETWEEN POST FORM AND THE POTENTIAL FOR ROOT FRACTURE ? • Henry ( 1977) - in a Photo elastic stress analysis – Threaded Post produce undesirable levels of stress.

• Standlee etal(1982)in a Photo elasticAnalysis“Tapered threaded post” are the worst stress producer. • Deutsch et al ( 1985) Tapered, threaded post increases root fracture by 20 TIMES that of a Parallel,threaded posts

CONCLUSIONS: • All types of threaded posts produce the greatest potential for root fracture(7%) compared with tapered cemented posts (3%)and parallel cemented posts(1%)

• WHAT IS THE PROPER LENGTH FOR A POST ?

Buranhan et all (1999): Finite Element Analysis study said that when teeth with diminished bone support ,stresses increase dramatically and are concentrated in the dentin near the root apex

• There is a relationship between post length and alveolar bone level • To minimize the stress in the dentin and in the post ,the post should extend more than 4mm apical to the bone.

CONCLUSIONS: 1.Make the post approx 3 / 4 the root length for long rooted teeth. 2. For average root length – post length is dictated by retaining 5mm of apical guttapercha.

HOW MUCH GUTTA-PERCHA SHOULD BE RETAINED TO PRESERVE THE APICAL SEAL ?

5mm (Though 4mm produces an adequate seal but radiographic angulation errors etc., can lead to lesser apical gutta-percha than 4mm, leading to failure because of leakage). Therefore 5mm should be retained.

CONCLUSION • 2 TO 3MM – HIGHEST LEAKAGE • 4 TO 5MM – ADEQUATE SEAL

DOES POST DIAMETER AFFECT RETENTION AND THE POTENTIAL FOR TOOTH FRACTURE ?

Studies relating retention to post diameter have produced mixed results

WHAT IS THE RELATIONSHIP BETWEEN POST DIAMETER AND THE POTENTIAL FOR THE ROOT PERFORATIONS?

• Answer: Lloyd and Palik (1993) There are presently three distinct philosophies concerning the preparation of dowel space for endodontically treated teeth.

The Conservationist: • This group generally advocates only minimal instrumentation of the canal after removal of guttapercha. • The instrumentation is limited to removal of undercuts that prevent withdrawal of dowel patterns, because endodontically treated teeth with the smaller diameter dowels resists fracture.

• Robbins specifically recommended the most conservative dowel that provided adequate retention without compromising the fracture resistance of the root.

• Goering and Mueninghoff recommended that dowel preparation should only minimally alter the internal anatomy of the canal.

• Gutman advocated only slight

enlargement of the existing canal anatomy for dowel space, referred to as “Internal

Shaping of the Canal”.

The Proportionist: • The development of a dowel space in proportion to the root structure is a concept perpetuated by many investigators and dentists. • Stern and Hirshtelo and Johnsot et al. recommended that the optimal diameter of the dowel was one third the diameter of the root.

• A-Dowel diameter should be no more than one third the root diameter at the CEJ

This clinical guideline for determining the appropriate diameter of dowel, according to Shillingburg and Kessler, generally involved the mesiodistal width of roots

Tilk et al. applied the “One Third Principle” in an exhaustive study of mandibular and maxillary root widths, and recommended ranges for dowel diameters for each tooth.

They suggested that the one third relationship preserved sufficient tooth structure to resist root fracture.

Shillingburg etal(1982)- measured 700 root dimensions to determine post diameter that would minimize risk of perforation Mandibular incisors- 0.6 - 0.7 mm Maxillary central incisor ,palatal root of maxillary first molar - 1.7 mm

Principal roots-for post space preparation: mandibular distal and maxillary palatal Mesial roots of mandibular molars and buccal roots of maxillary molars should not be used for post owing to higher risk of perforation on the furcation side of the root

The Preservationist: The philosophy of dowel space preparations depends on a minimal thickness of dentin surrounding the entire dowel to prevent tooth fracture. Caputo and Standee proposed that at least 1mm of sound dentin be maintained around the entire circumference.

Hail et al. compared in vitro prefabricated the custom dowels and cores and concluded that the ideal was 1.75mm of tooth structure remaining in any direction from the margin of the prepared dowel.

• CAN GUTTA PERCHA BE REMOVED IMMEDIATELY AFTER ENDODONTICALLY TREATED AND POST SPACE PREPARED? Answer : Adequately condensed guttapercha can be safely removed immediately after endodontically treatment.

• WHAT INSTRUMENTS REMOVE GUTTA- PERCHA WITHOUT DISTURBING THE APICAL SEAL? Instruments used for removal for gutta- percha  Gates- Glidden- Burs  Paeso reamers  Warm Plugger GPX Bur

The root canal system should first be completely obturated A post cannot be placed if the canal is filled with a full-length silver point,so these must be removed and the tooth retreated with gutta-percha

There are two commonly used methods to remove guttapercha: One uses a warmed endodontic plugger Other uses a rotary instrument,which is sometimes used in conjunction with chemical agents.

Although it is more time consuming the warmed endodontic plugger is preferred because it eliminates the possibility that the rotary instrument will inadvertently damage the dentin.

If the gutta-percha is old and has lost its thermoplasticity,use a rotary instrument, Make sure that it follows the gutta-percha and does not engage dentin(this will cause a root perforation) For this reason,high-speed instruments and conventional burs are contraindicated.

Peeso-reamers and Gates Glidden drills are often used for this purpose. These are considered ‘safe-tip’ instruments because they are not end-cutting burs. The friction generated between the fill and the tip of these burs softens the guttapercha,allowing the rotary instrument to track the canal with reasonable predictability.

The gates glidden drill has a long thin shaft ending in a flame shaped Peeso reamer has long sharp flutes connected to a thick shaft.It should be used with caution as it tends to remove all the guttapercha or also cause perforation the root

• CONCLUSIONS: Both rotary and hot hand instrument can be safely used to remove adequately condensed gutta percha when 5 mm are retained apically.

• CAN A PORTION OF A SILVER POINT BE REMOVED AND STILL MAINTAIN THE APICAL SEAL ? Removal of a portion of a silver point during post preparation causes apical leakage.

DOES THE USE OF A “ CERVICAL FERRULE” (CIRCUMFERENTIAL BAND OF METAL) THAT ENGAGES TOOTH STRUCTURE HELP PREVENT TOOTH FRACTURE? • FERRULE: Brown gave the origin of this word from Latin word for iron( Ferrum ) and Bracelets ( Viviola).

 Ferrule can be defined as a metal ring or cap put around the end of a tool or cane to give added strength ”  A dental ferrule is an encircling band of cast metal around the coronal surface of the tooth.  There are two types of ferrule. 1. Crown ferrule. 2. Core ferrule.

• Ferrule effect has been shown to significantly increase the fracture resistance of an endodontically treated tooth by counter acting functional stress such as lever forces and wedging effects

• This effect is used in the dowel preparation in the form of circumferential contrabevel • This contrabevel reinforces the coronal aspect of dowel preparation • This effect can be used when there is little or no clinical crown remaining

CONCLUSIONS: -

Differences of opinion exist regarding the effectiveness of ferrules in preventing tooth fracture Ferrules have been tested when they are part of the core and also when the ferrule is created by the overlying crownengaging tooth structure.

Most of the data indicate that a ferrule created by the crownencompassing tooth structure is more effective than a ferrule that is part of the post and core. Ferrules that grasp larger amounts of tooth structure are more effective than those that engage only a small amount of tooth structure.

Treatment Planning: -

The teeth should have the following characteristics before going for post and core fabrication.  Good apical seal  No sensitivity to percussion or biting pressure.  No exudates  No fistula  No apical sensitivity.  No active inflammation.

Treatment goals Maintain the coronal and apical seal of the root canal filling materials Protect and preserve the remaining tooth structure Provide a supportive and retentive foundation for placement of a definitive restoration Restore function and esthetics

All the changes that accompany RCT influence the selection of restorative procedures.

Important include

considerations

1.The amount of remaining tooth structure. 2.The anatomic position of the tooth- anterior, posterior. 3.The functional load on the tooth.

Key features of an endodontically treated tooth include  Adequate Apical seal Minimal canal enlargement Adequate Post Length Positive Horizontal Stop Anti rotation Margin design

• Anti rotation: includes using pins or key ways or preparing remaining coronal tooth structure • Positive stop:of the core on to sound dentin is required to prevent of wedging effect that could contribute to root fracture

Ideal Properties Of A Dowel:  Maximum protection to root.

Adequate retention within the root Maximum retention of the core and crown. Maximum protection of the crown margin cement seal.

Pleasing esthetics when indicated High radiographic visibility. Retreivability. Biocompatibility.

Tooth Preparation

Retention form Preparation geometry Post length Post diameter Post surface texture Luting agent

Post length

• Short posts ,root fracture is common because of their failure to be completely surrounded by peri radicular bone

• Rosen et al stated that the apical extension of the dowel should reach a point which lies at least half way between the apex of the root and alveolar crest

• A dowel with sufficient apical extension will prevent root fracture

The fulcrum point of a short post is closer to the occlusal table. Goldrich recommends the ideal post length as long as the clinical crown being restored

Resistance form a)Stress distribution Stresses are reduced as post length increases

Rotational resistanceauxiliary pin,small groove placed in canal.

• The depth of insertion of the pesso reamer is determined by superimposin g it over a radiograph of the tooth being

• Canal is prepare d with peaso reamers

The dowel space preparation is finished

Custom made post Custom made post can be cast from the direct pattern or indirect pattern

A direct technique using autopolymerizing technique is recommended for single canals. whereas the indirect procedure is more appropriate for multiple canals.

Direct Procedure 1.Lightly lubricate the canal and notch a loose-fitting plastic plastic dowel. 2.Use the bead-brush technique to add resin to the dowel and seat it in the prepared canal

• Preformed Plastic form is trimmed to fit loosely into the canal

This should be done in two steps:  Add resin only to the canal orifice first.  An alternative is to mix some resin and roll it into a thin cylinder.  This is introduced into the canal and pushed to place with the monomer-moistened plastic dowel

Do not allow the resin to harden fully within the canal.loosen and reseat it several times while it is still rubbery. Once the resin has polymerized,remove the pattern.

• Plastic pin is notched to retain the resin • After this pattern has set ,a second mix is then added to build up

• Coronal portion of acrylic pattern is prepared for final restoration

The post pattern is complete when it can be inserted and removed easily without binding in the canal.

Once the pattern has been made,the acrylic pattern is cast .

Pattern Fabrication Thermoplastic Post:

With

 The canal is lubricated and excess lubricant is removed with paper points The post was previously trimmed until its beveled portion protrudes about 1.5-2 mm above tooth preparation

• Heat the thermoplastic resin over a flame • The plastic rod is covered for two thirds of its anticipated length • The coated post is inserted and can be removed in 5-10 seconds

• After any protrusions have been removed ,the core is built up and trimmed to ideal tooth preparation form

Indirect Procedure Cut pieces of orthodontic wire to length and shape them like a letter J Verify the fit of the wire in each canal Coat the wire with tray adhesive .Lubricate the canals to facilitate easy removal of impression without distortion

Using a lentulospiral,fill the canals with elastomeric impression material

Seat the wire reinforcement to full depth of each post space,syringe impression material around the prepared teeth,insert the impression tray

Remove the impression ,pour the working cast Lubricate the cast Add inlay wax in increments Wax core can be shaped

Restoration with a Prefabricated Post

Before cementing the post confirm the length of the post corresponds to the length of the newly created post space Use cylindrical diamond or carbide bur to prepare anti rotational box Place the post in to the post space

• A micro etcher allows air abrasion surface treatment with a 50 micron aluminium oxide

• Air abrading the entire surface before cementation increase retention

• Place the cement in the canal with the lentulo spiral. • This results in an even coating of cement

• Tooth preparation for final crown is complete

ESTHETIC QUALITIES OF DOWEL:• Current restorative procedure allows fabrication of highly esthetic, ceramic coronal restorations that contain no metal substructure.

• These restorations can have remarkable depth of lifelike color and vitality, with no unnatural opacity, shadows, gray colorations, or artificial brightness from underlying metal

• Esthetic restoration of non vital teeth is also possible today, with the development of white or tooth- colored , dowel and core material.

Dowel selection for the esthetic case will depend on Evaluation of desired physical properties of the esthetic dowels The amount of remaining tooth structure

• Dowel materials should be inert to the corrosive effects of oral fluids because no dowel and cement combination has been shown to form a liquid proof seal against micro leakage.

• Corrosion is not an issue with nonmetallic dowels or with custom- cast dowel and cores if the cast dowel and core are fabricated completely from non reactive gold alloys. • The most significant corrosion occurs is Stainless Steel dowels when a custom core is cast onto a preformed metal dowel.

CORE Consists of restorative materials placed in the coronal area of tooth replacing carious, fracture or otherwise missing coronal structure and retains the final crown.

Desirable physical characteristics of a core include the following : • High compressive strength. • Dimensional stability. • Ease of manipulation. • Short setting time for cement. • An ability to bond to both tooth and dowel.

CAST CORE



A cast metal dowel and core is the traditional way to restore endodontically treated teeth

 Noble corrosive

metals

are

non

Disadvantage Of cast dowel and cores have a higher rate of root fracture Secondly ,the financial cost service is high Casting can result in porosity ,resulting in fracture of the metal.

• Amalgam Core-are highly retentive but has a potential for corrosion and subsequent discoloration of the gingiva or remaining dentin • Amalgam use is declining world wide ,because of safety and environmental issues. • Composite resin core

Glass ionomer core It is indicated when • Significant sound dentin remains • Additional retention is available with pins or dentin preparations • Moisture control is assured • Caries control is indicated

• Provisional Restorations (Temporization) To prevent drifting of opposing or adjacent teeth, an endodontically treated tooth requires a proper provisional restoration immediately following completion of endodontics.

• Of particular importance are good proximal contacts to prevent tooth migration leading to unwanted root proximity. • If a cast post-and –core is made an additional provisional restoration is needed while the post-and-core is being fabricated.

• This can be retained by fitting a wire (e.g., a paper clip or orthodontic wire ) into the prepared canal. • The restoration is then conveniently fabricated with auto polymerizing resin by the direct technique.

Removal Of Existing Posts: • Occasionally an existing postand-core must be removed (e.g., for retreatment of a failed root canal filling.). • Patients must understand in advance that post removal is a risky process and occasionally results in radicular fracture.

If sufficient length of post is exposed coronally, the post can be retrieved with thinbeaked forceps Vibrating the post first with an ultrasonic scaler will weaken brittle cement and facilitate removal A thin scaler tip or special post removal tip is recommended.

 Although histological

examination with animal models shows no harmful effect in the periodontal tissues,ultrasonic removal is slower than other methods and may result in an increased number of canal and intradentin cracks.

Alternatively, a post puller can be used. This device consists of a vise to grip the post and legs that bear on the root face. A screw activates the vise and extracts the post

A post that has fractured within the root canal be removed with a post puller or forceps. The post can be drilled out, but great care is needed to avoid perforation. The technique is best limited to relatively short fractured posts.

Another means of handling an embedded fractured post (described by Masserann in 1966)uses special hollow endcutting tubes(or trephines)to prepare a thin trench around the post. This technique has shown success

Historically, key criteria for dowels was rigidity to resist bending under function Today there are dowels with physical properties that resemble those of dentin, in addition to addressing all other clinical retention, esthetic, and radiographic issues.

Occlusal forces are transferred through the core to the dowel and ultimately disbursed along the length of the root. The more similarly dowels , cements and restorative materials behave in comparison to dentin, the less force is concentrated among the components and the root during function.

• However, successful restoration of endodontically treated teeth includes more than root fracture resistance. • Function and esthetics must be restored, and this restored dentin dowel core and cement- crown complex must remain intact and resist micro leakage and recurrent caries over time.

Cast Post

• Least retentive of all post • Generates high levels of wedging stress • Indicated when canal system has been over prepared / in incomplete root

Stainless Steel • Posts are available in wrought,precious & non-precious alloys. • Can be used with a variety of direct and indirect techniques

Recent Advances in Posts

Flexi Post • Flexi-post is the patented splitshanked,parallelthreaded posts

Through the incorporation of the spilt shank,the stresses of insertion are absorbed by the post(not the root) during placement The design distributes functional stresses evenly around the embedded blades Parallel sided threads cut into dentin rather than pushing it away.

This maximizes retention without contributing to the production of tensile stresses. The entire length of shank is vented which releases internal hydrostatic pressure upon cementation.

• Based on the studies “The flexi

post system displayed twice the retention of the other systems evaluated”

Endopost

High fusing precious metal alloy It was the first of the practical manufactured aids to post fabrication that consistently & reliably afforded post length and

Composi post Carbon fiber reinforced root canal post. In 1990 ,Duet et al,described a nonmetallic material for the fabrication of posts based on the carbon-fiber reinforcement principle.

Carbon fiber posts are made of unidirectional carbon fibers embedded in an epoxy matrix.

The resulting post is strong but has significantly lower stiffness and strength when compared to ceramic and metal post.

• One advantage of a carbon fiber post is the ease of its removal for retreatment. • The very strong carbon fibers prevent the drill from tracking laterally, avoiding penetration of the dentin. • Therefore, if concern exists about the long term prognosis of an endodontically treated tooth, a carbon fiber post should be considered.

• The chief disadvantage of a carbon fiber post is its black appearance, which presents an esthetic problem ( as can metal posts).

Carbon fiber/epoxy showing through the facial surface of the composite build-up can prohibit the use of an all ceramic crown.

• The newer carbon fiber post comes with a quartz exterior that makes the post tooth colored which is more esthetic.

Carbon fiber and metal dowels are not esthetic and should be not be used for esthetically critical restorations. They are appropriate for teeth to be resorted with gold or porcelain fused- to metal crowns.

Luscent Anchor Post • The luscent anchor post (Dentatus) is a fiber glass,clear resin post

It is designed to refract & transmit natural tooth colors for esthetic post & foundations. Is Radiolucent Designed to be placed passively in prepared canals Available in 3 diameters.

Parapost Fiber White Posts • A filled resin,mono-directional fibers matrix with a flexural modulus that very closely approximates that of the natural dentin • White translucent • Available in four diameters

Ceramic Post Indications Teeth requiring very translucent allceramic crowns Contra-indications Metallic ceramic crown is planned

• Advantages Esthetics • Dis-advantages Cost Long term data are limited Ceramic materials may have a tendency to fracture

• Zirconia dowels are highly radio plaque and visible on radiographic films, but they are stiffer than dentin. • Zirconium can therefore, be considered an esthetic equivalent to preformed metal dowels, they are highly bondable to the root structure

• Zirconium is extremely hard and cannot be cut from a canal: the length must be trimmed before cementation

• The Post Endodontic Treatment of Teeth Presents the Dental Practitioner With the Dilemma of Selecting From a Large Array of Materials,techniques and Designs.

• Today, the Endodontic and Prosthodontic aspects of treatment have advanced significantly, new materials and techniques have been developed, and a substantial body of scientific knowledge is available on which to base clinical treatment decisions.

Bibliography • Harty’s Endodontics in clinical practicePitt Ford • Endodontic therapy- Franklin Weine • Pathways of the pulp- Cohen and burns • Endodontic practice- Grossman • Color atlas of Endodontics- William Johnson • Practical Endodontics- a clinical guideEdward Besnor • Endodontics- E.Nicholis • Ingle –2002 edition

• Principles of preparing endodontically treated teeth for dowel and core restorations-JPD Aug 1973 • The Prosthodontic use of endodontically treated teeth:theory and biomechanics of post preparation.JPD Feb 83 • Management of endodontically treated teeth,JPD April 1983 • Restoration of endodontically treated teeth – Dental clinics of North America

Fundamentals of tooth preparations for cast metal and porcelain restorations. Shillinburg HT Jr. Quintessence Publishing Co. Inc. 1987 Fundamentals of Fixed ProsthodonticsShillingburg Contemporary Fixed Prosthodontics. Rosenstiel Tylman’s Theory and Practice of fixed Prosthodontics. 8th edition. All India Publishers and Distributors