R ESTORATIVE CONSIDERATIONS FOR ENDODONTICALLY TREATED TEETH. ADA Meeting 19 July 2011

Endodontics The branch of dentistry that deals with maintaining healthy dental pulp in a state of health and the treatment of diseased dental pulp to promote healing and restoring the health of the tooth and the surrounding peri-radicular tissues to maintain the function and aesthetics of the teeth.

The Consultation - History - Exam - Diagnosis - Treatment plan - Treatment - Recall

The Plan Coronal Restoration - Remaining tooth structure - Periodontium - Strategic importance - Occlusion - Material(s) - Additional Retention - Nayyar technique - Posts? - PINS Root Canal Treatment - Non-surgical - Surgical

Do we need posts?

Posts Posts DO NOT strengthen root filled tooth They retain the core NO POST is the best option However……….

Posts Type - Prefabricated not cast post

Posts Shape – Parallel sided not tapered

Posts Length – Long not short The Crowbar Effect

Posts Diameter – Debatable α material

Posts Material – Rigid and not flexible Gold, fibre such as carbon, glass, or even zirconia, or stainless steel, or titanium

Posts Design – Serrated (not smooth or screw type) Serrated Smooth Screw

Posts Cement – Type and amount Whatever type of cement that is used for the post it t must fit loosely in the canal. If you are a getting a tug back with your post, you have a problem.

Case

Prefabricated Long Thick Serrated Parrallel Rigid Cement Clinical Guidelines

What core material do you use?

Final Restoration/Core

Direct restoration Amalgam Advantages - Proven track record - Quick and easy to place - Relatively Inexpensive - Good coronal seal Disadvantages - Mercury - Colour - Does not bond to teeth - Require retentive features

Composite Advantages - Matches tooth colour - Less toxic - Minimal preparation - Bonds to teeth Disadvantages - Technique sensitive - Coronal leakage Direct restoration

Glass Ionomer Advantages - Matches tooth colour - Less toxic - Minimal preparation - Moisture tolerant - Releases flouride Disadvantages - Technique sensitive - Weak Direct restoration

Indirect CAD/CAM – CD4, Cerec Advantages - Matches tooth colour - Less toxic - Quick turn-around - Bonds to teeth Disadvantages - Technique sensitive - Brittle - Cost - set up - patients In-direct restoration

Indirect lab based – Gold, PFM, PJC, Zirconia Advantages - Matches tooth colour - Less toxic - Good seal - Restores tooth resistance Disadvantages - Time consuming - Brittle – (Porcelain) - Cost - Delayed In-direct restoration

Clinical Guidelines

A virgin tooth is prestressed where the cusps are in constant tension pushing towards each other to allow for the flexing occlusal forces. Occlusal filling – 20 %. I will happily replace this with amalgam or composite. MO or DO – 40 % I would restore them with amalgam or composite. However as soon as you roughly lose just over 2/3(M-D) x 1/3 (B-L) of the tooth I would seriously consider cusp capping with amalgam or composite MOD – 60 % At this stage, I will do a full coverage restoration with amalgam or composite If a cusp is missing then the ability to withstand fracture reduces even further. When restoring a tooth, one must look at the remaning tooth structure and then decide what filling they will do. This is the primary determining factor. The aim of the game to restore the tooth to as close to its original state.

Do all root filled teeth require crowns? The routine use of posts and cores in anterior teeth is not required unless there is gross loss of coronal tooth structure. In fact there is lesser leakage with a bonded composite that a post core and crown. If you are going to make a veneer, you are better off making a crown. Generally too much tooth structure is lost to make a nice veneer so crown the tooth especially if it is heavily filled Root canal treated posterior teeth, usually needs a crown when they are cusp capped. As a general rule, It can increase the chances of success by 6-11 fold. In any case the core material that is used does not matter if there is sufficient tooth structure to provide a ferrule effect.

The Ferrule When using a core build up in either anterior or posterior teeth, ideally there must be at least 2 mm of sound tooth structure above the free gingival margin for the placement of a crown. This is the ferrule. This increases the resistance of teeth to fracture and also allows for the margins from getting plaque accumulation and subsequent secondary decay. 1mm ferrule double the resistance to fracture. Uneven ferrule is better than no Ferrule. So dont pick up that bur and trim the last remaining millimetre of supra-gingival tooth just so that your cast post is easier to fit.

Crown Lengthening Surgery 1.0 mm cemetal-fibrous interface, 1.0 mm epithelial attachment, 1.0 mm sulcus 1.0 mm finishing margin = 4.0 mm above crestal bone Orthodontic extrusion is better than CLS

How long before a crown Review in 6 months to check for healing. If no change. Review in another six months. Crown when healing visible at the recall. If crowning will reduce the chances of leakage such post core crown for anteriors. Crown immediately after RCT.

Is coronal seal more important?

The coronal seal is NO more important than the root filling itself. The Coronal Seal Adequate root filling Coronal seal

Clinical Guidelines Timing of final restoration Tooth fracture prior to final restoration; Inadequate final restoration – lacks ideal marginal integrity – forces of occlusal function – deterioration Recurrent decay

How do we improve our success rate?

Pathway to success

Sensibility test

Pathway to success Correct diagnosis

Pathway to success Rubber dam isolation

Adequate Access Pathway to success

Locate all the canals MB 2 is Not a Myth!!

Thorough chemo-mechanical preparation Pathway to success

Well constructed provisional restoration Pathway to success

Unidentified Iatrogenic damage Pathway to success Perforation

Produce an acceptable root filling and construct a good coronal seal Pathway to success

Outcomes Favourable - Healing - Pre-operative PA area 73%-97% - More than 2 roots 84% - No pre-operative PA area 88%-97% - Single rooted teeth 93% Overall -Healing 41% - 86%

Conclusion Each case must be treated on its own merit There is no recipe to ensure success Ensure correct informed consent Refer if unsure Do or do not... there is no try. – Yoda