Restoration of endodontically treated tooth Amalgam resin composite

Restoration of endodontically treated tooth

• Amalgam, resin composite, and glass ionomer in combination with a prefabricated post • Amalgam had the lowest failure rate, • Glass ionomer core buildup materials caused the greatest number of failures • R. E. Kovarik, L. C. Breeding, and W. F. Caughman, “Fatigue life of three core materials under simulated chewing conditions , ” The Journal of Prosthetic Dentistry, vol. 68, no. 4, pp. 584– 590, 1992

• Some studies supported the use of amalgam dowels in the root canals • Tamse compared 49 mesial roots extracted due to vertical fractures with 52 mesial mandibular roots without fractures, • and found that 67. 3% of the vertically fractured roots had an amalgam dowel in the coronal part (1 -2 mm) of the root.

• In another study, endodontically treated teeth not crowned after obturation were lost 6 times more often than teeth crowned after obturation • S. A. Aquilino and D. J. Caplan, “Relationship between crown placement and the survival of endodontically treated teeth , ” The Journal of Prosthetic Dentistry, vol. 87, no. 3, pp. 256– 263, 2002.

• A 10 -year prospective clinical trial, showed 94% survival rate of metal post-and-cores with a crown • G. Heydecke and. M. C. Peters, “The restoration of endodontically treated, single-rooted teeth with cast or direct posts and cores: a systematic review, ” The Journal of Prosthetic Dentistry, vol. 87, no. 4, pp. 380– 386, 2002.

• Another 17 -year controlled prospective study showed that the type of core restorations under the crowns had no effect on the survival rate of 307 endodontically treated teeth • W. A. Fokkinga, C. M. Kreulen, E. M. Bronkhorst, and N. H. J. Creugers, “Up to 17 -year controlled clinical study on postand- cores and covering crowns, ” Journal of Dentistry, vol. 35, no. 10, pp. 778– 786, 2007.

Post-core • The use of posts does not reinforce endodontically treated teeth and some reports even show that teeth which were restored without a post and core are less susceptible to fracture than teeth with post and core • A. Smidt and E. Venezia, “Techniques for immediate core buildup of endodontically treated teeth, ” Quintessence International, vol. 34, no. 4, pp. 258– 268, 2003

Post-core • Its success relies on the success of the entire system and vice versa. • For anterior restorations, consider using a ceramic or light-colored fiber post made of quartz, silicone or glass fibers.

Post Shape • Posts come in three basic shapes: parallel, tapered, and parallel-tapered

Parallel • Parallel posts are more retentive than tapered ones. • They seem less likely to cause root fractures, distributing stresses evenly along their length. • However, parallel posts require removal of more tooth structure than tapered ones and, therefore, may not be suitable for roots with thin walls.

Tapered • Tapered posts allow for minimal dentin removal since most roots themselves are tapered. • The stresses absorbed by these posts are concentrated in the apex • Creating a wedging effect and increasing the risk of vertical root fracture. • Because of this increased risk when tapered posts fail, they are more likely to leave the tooth unrestorable.

Parallel-tapered • Advantages of both designs with few reported disadvantages. • This post has a parallel shaft, tapering at the apical end. • This mix achieves retention associated with parallel sides, while allowing tooth preservation at the apex.

Length and Diameter • Post retention improves with increases in post length, rather than diameter. • An increase in post length with a minimum diameter preserves tooth structure and reduces shear stresses and risk of fracture.

• Diameter is important for strength and resistance to post fracture • Sequential use of post twist drills, starting with narrowest and working up to the desired post diameter, can be useful in minimizing tooth loss during post-space preparation. [

The groove is normally located where the root is bulkiest, usually on its lingual aspect. Rotational resistance in an extensively damaged tooth can be obtained by preparing a small groove in the root canal. This must be in the path of placement of the post and core.

Influence of post and cores on light transmission through all-ceramic crowns • Some ceramic systems are semi-translucent (IPS Empress®, Ivoclar Vivadent) • Others are semi-opaque (In-Ceram®, Vident, Brea, CA). • A traditional metal post (gold or titanium) results in poor esthetics because of the lack of light transmission.

• . Metallic posts also create a light blue/gray appearance at the gingival margin, possibly as a result of shadows.

Metal post • • • Esthetic Corrosion reactions Taste Oral burning Oral pain Sensitization and other allergic reactions • • Hayashi Y, Nakamura S. Clinical application of energy dispersive x-ray microanalysis for nondestructively confirming dental metal allergens. Oral Surg Oral Med Oral Pathol 1994; 77: 623 -626

Radiopacity FRC Postec shows reduced radiopacity Used in conjunction with Variolink II provides additional x-ray identification

Removal FRC Postec can be removed with a rotary instrument if retreatment is required

Zirconia posts • • • Meyenberg Good chemical stability Mechanical strength High toughness Color similar to that of natural teeth • • Ahmad I. Yttrium–partially stabilized zirconium dioxide posts: an approach to restoring coronally compromised nonvital teeth. Int J Periodontics Restor Dent 1998; 18: 454 -465.

Zirconia posts • Nearly impossible to remove • Removal of zirconia post by ultrasonic causes temperature rise of the post and on the root surface

Zirconia post • Cormier et al: fracture strength of zirconia post varied according to the different stages of tooth restoration. • When the post alone was bonded into tooth, fracture strength was 101. 5 N; • when the post was bonded into tooth with core buildup, fracture strength was 179. 7 N; • with post and core buildup as well as full veneer restoration, fracture strength was 238. 8 N • Cormier CJ, Burns DR, Moon P. In vitro comparison of the fracture resistance and failure mode of fiber, ceramic and conventional post systems at various stages of restoration. J Prosthodont 2001; 10: 26 -36.

• The bond strengths of luting agents to zirconia posts were measured without bonding to any tooth structure, and it was shown that a dual-cured resin cement, Panavia (Kuraray, Osaka), produced better results than other cement types • Sahmali S, Demirel F, Saygili G. Comparison of in vitro tensile bond strengths of luting cements to metallic and tooth-colored posts. Int J Periodontics Restor Dent 2004; 24: 256 -263.

• The reviewed studies suggested that FRC and zirconia posts might be the preferred clinical choice for preventing coronal microleakage • • • Jung SH, Min KS, Chang HS, Park SD, Kwon SN, Bae JM. Microleakage and fracture patterns of teeth restored with different posts under dynamic loading. J Prosthet Dent 2007; 98: 270 -276 Reid LC, Kazemi RB, Meiers JC. Effect of fatigue testing on core integrity and post microleakage of teeth restore with different post systems. J Endod 2003; 29: 125 -131 Usumez A, Cobankara FK, Ozturk N, Eskitascioglu G, Belli S. Microleakage of endodontically treated teeth with different dowel systems. J Prosthet Dent 2004; 92: 163 -169

• zirconia posts showed the highest radiodensity level, followed by metallic posts, carbon fiber posts, glass fiber posts, and carbon fiber post covered with quartz fiber.

• In a study by Dietschi et al. • It was reported that the carbon fiber post presented the lowest marginal gap proportion (7. 11%) compared to other post types which • presented higher degrees of marginal gap formation: • titanium post at 11%, zirconia post at 16. 5%, and • stainless steel post at 17. 4% • Dietschi D, Ardu S, Rossier-Gerber A, Krejci I. Adaptation of adhesive post and cores to dentin after in vitro occlusal loading: evaluation of post material influence. J Adhes Dent 2006; 8: 409 -419.

• A) a flame heated endo plugger, • B) Gates. Glidden drills • C) GPX drills

sixty-six extracted maxillary central Removed from CEJ Ah 26 Six teeth were used as positive and negative control • other sixty teeth were divided into 3 groups, each group containing 20 teeth • apical dye leakage in each group was measured by astereomicroscope • •

• Minimal mean dye leakage was related to the hot plugger group • Maximum mean leakage was observed in Gates glidden drill group

• Kwan and Harrington (1981) and Madison and Zakariasen (1984) found that post space preparation with Gates Glidden drills immediately after obturation actually decreased the amount of apical leakage.

Flame-heated endo pluggers Fast Inexpensive don‘t cause canal shape alterations Burn potential for the dentist, dental assistant or the patient • did not cause any permanent damage to the • periodontium • •

Peeso reamers • Very fast • Creates parallel walls which provide optimal retention form for the post • possiblity of creating root perforation, canal transportation, overenlargement of the canal • Only in straight canals

• The gates glidden drills are more conservative instruments compared with Peeso reamers drills

GPX • match standardized endothontic file sizes # 25 #50. • Slight frictional heat which softens the GP before removal • Fast and effective • The bur does not engage the dentin so canal shape remains unaltered and the frictional heat generated is minimal