This document discusses the ferrule effect in restoring endodontically treated teeth. It defines a ferrule as a band of metal encircling the coronal tooth structure that extends at least 1.5-2mm below the finish line. The presence of a ferrule helps resist fracture by reinforcing the tooth against lever forces and post insertion stresses. It also helps prevent root fractures. An adequate ferrule requires sufficient height, width, and number of surrounding walls. Teeth can be classified based on their ferrule characteristics into categories with varying risk levels. When little structure remains, crown lengthening or orthodontic extrusion may help create a ferrule, but extraction may be a better option if
The patient who requires a single denture opposing a natural or restored dentition challenges the clinician even more than the completely edentulous patient does. This is due to the biomechanical differences in the supporting tissues of the opposing arches. So a proper evaluation, correction of the existing factors and proper sequence of denture construction is necessary to give a more stable prosthesis.
a detailed account of the principles of tooth preparation with main reference from Shillingburg
The presentation is available on request. Mail me at apurvathampi@gmail.com
Fixed partial dentures transmit forces through the abutments to the periodontium. Failures are due to poor engineering, the use of improper materials, inadequate tooth preparation, and faulty fabrication. Of particular concern to prosthodontist is the selection of teeth for abutments. They must recognize the forces developed by the oral mechanism, and resistance.
Successful selection of abutments for fixed partial dentures requires sensitive diagnostic ability. Thorough knowledge of anatomy, ceramics, the chemistry and physics of dental materials, metallurgy, Periodontics, phonetics, physiology, radiology and the mechanics of oral function is fundamental.
A concise and brief presentation on cleaning and shaping of root canals. Colorful and well pictured. Ideal for UG students and PG students to get a good understanding of BMP techniques.
Protaper means progressively taper.
•NiTi
Protaper means progressively taper.
•NiTi
Increased flexibility
• Each instrument produces its own 'crown down effect' as larger tapers make way for smaller tapers.
• Protaper files engage a smaller area of dentine reducing torsional loads and file fatigue
The patient who requires a single denture opposing a natural or restored dentition challenges the clinician even more than the completely edentulous patient does. This is due to the biomechanical differences in the supporting tissues of the opposing arches. So a proper evaluation, correction of the existing factors and proper sequence of denture construction is necessary to give a more stable prosthesis.
a detailed account of the principles of tooth preparation with main reference from Shillingburg
The presentation is available on request. Mail me at apurvathampi@gmail.com
Fixed partial dentures transmit forces through the abutments to the periodontium. Failures are due to poor engineering, the use of improper materials, inadequate tooth preparation, and faulty fabrication. Of particular concern to prosthodontist is the selection of teeth for abutments. They must recognize the forces developed by the oral mechanism, and resistance.
Successful selection of abutments for fixed partial dentures requires sensitive diagnostic ability. Thorough knowledge of anatomy, ceramics, the chemistry and physics of dental materials, metallurgy, Periodontics, phonetics, physiology, radiology and the mechanics of oral function is fundamental.
A concise and brief presentation on cleaning and shaping of root canals. Colorful and well pictured. Ideal for UG students and PG students to get a good understanding of BMP techniques.
Protaper means progressively taper.
•NiTi
Protaper means progressively taper.
•NiTi
Increased flexibility
• Each instrument produces its own 'crown down effect' as larger tapers make way for smaller tapers.
• Protaper files engage a smaller area of dentine reducing torsional loads and file fatigue
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
Rehabilitation of endodontically treated teeth : Post & CoreNaveed AnJum
These days we often come across mutilated or badly broken teeth in our practice. However various factors are involved for a better prognosis of such a teeth. This presentation mainly focuses on post and core treatment of such a teeth.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
3. Introduction
◦ Successful clinical outcome of an endodontically treated tooth depends not
only on adequate root canal treatment but also on an adequate restorative
treatment which is performed afterwards.
◦ A RC treated tooth is inherently compromised because of the loss of firm
coronal dentin, instrumented canals and hence increased flexure in response to
occlusal forces.
◦ When a tooth has suffered significant structure loss, the restorative options may
include restoring the tooth with various involved procedures or extracting the
tooth.
3
4. ◦ The longevity of endodontically treated tooth is directed related to the amount
of remaining sound tooth structure.
◦ When restoring these cases, the restoration’s ability to brace solid sound tooth
structure is the key for long-term success.
◦ Successful restoration of a root filled tooth should provide:
◦ 1. Effective coronal seal
◦ 2. Protection of remaining tooth structure
◦ 3. Restored function
◦ 4. Acceptable aesthetics
◦ And to fulfil all these requirements, a post retained crown is usually indicated.
◦ At one time dowel was thought to strengthen the remaining tooth structure
and was referred to as Intra-coronal Crutch by Rosen.
4
5. ◦ However, root fracture is one of the most common modes of failure of these
restorations.
◦ Fractured post, cores or roots of further crowned endodontically treated teeth
are disappointing clinical outcomes.
◦ Hence, for an attempt to reduce the failure when restoring such teeth,
incorporating certain designing features during the tooth preparation is
important. Ferrule is one of them.
◦ The incorporation of the long standing concept of ‘ferrule’ or ‘the ferrule
effect’ has been accepted as one of the foundations of the restoration of the
endodontically treated tooth that has suffered advanced structure loss.
5
7. A ferrule, in respect to
teeth, is a band that
encircles the external
dimension of residual
tooth structure.
A dental ferrule is an
encircling band of cast
metal around the coronal
surface of the tooth.
(Galen WW, Mueller KI: Restoration of the Endodontically Treated Tooth. In Cohen, S. Burns, RC, editors: Pathways of the
Pulp, 10th Edition.) 7
8. ◦ Extending a preparation apically
creates a ferrule and helps
prevents fracture of an
endodontically treated tooth
during function.
◦ A Prepared with a ferrule
(arrows).
◦ B Prepared without a ferrule.
8
9. •The role of a dental ferrule, is embracement of the hard tissue by
crown restoration of a certain height which is mandatory for a post-
endodontic reconstruction of severely damaged teeth.
•A dental ferrule preparation combines a shoulder preparation with
parallel coronal dentin walls.
•The tooth tissue is enclosed by the crown improving the overall
resistance of the restoration
9
10. DEFINITION
The ferrule effect can be defined as ‘‘a 360
metal collar of the crown surrounding the
parallel walls of the dentine extending coronal
to the shoulder of the preparation”.
(Sorensen & Engelman)
10
11. MISINTERPRETED AS..
• The remaining amount of sound dentine above the finish line.
• It is in fact not the remaining tooth structure that is the ‘ferrule’ but rather the actual
bracing of the complete crown over the tooth structure that constitutes the ferrule
effect, i.e. the protection of the remaining tooth structure against fracture.
Jotkowitz A:Rethinking Ferrule:a new
approach to an old dillemma.British
Dental Journal,2010;209(1):25-33 11
14. FERRULE ADVANTAGES:
There are four advantages of this effect:
1:Promotes embracing actionofartificialcrownagainstdentin,
2:Preventstheshatteringoftheroot,
3:Reducesthewedgingeffectofatapered dowel,and
4:Resistsfunctionalleverforcesandthelateral forcesexertedduring
dowelinsertion.
RosenH:Operativeproceduresonmutilatedendodonticallytreatedteeth.JProsthet Dent1961;11:973-986.
SorensenJA,EngelmanMJ:Ferruledesignandfractureresistanceof
endodonticallytreatedteeth.JProsthetDent1990;63:529-536
14
15. •The use of a ferrule as part of the core or artificial crown may be of benefit in
reinforcing root-filled teeth.
•A protective ‘ferrule effect’ could occur owing to the ferrule resisting
stresses such as
•functional lever forces,
•the wedging effect of tapered posts and
•the lateral forces exerted during the post insertion.
(Sorensen & Engelman1990).
15
16. CROWN FERRULE: Ferrules created by the
overlying crown engaging tooth structure.
CORE FERRULE: Ferrules that are part of a
cast metal.
16
18. Four direct factors influencing the ferrule as well as two additional indirect
factors that may influence the functionality of the ferrule:
◦ a) Ferrule height
◦ b) Ferrule width
◦ c) Number of walls and ferrule location
◦ d) Type of tooth and the extent of lateral loads
◦ e) Type of post
◦ f) Type of core material.
18
19. •1.Ferrule height
Greater the height of remaining tooth structure
better the fracture resistance.
Ferrule height of 1.5 to 2 mm of vertical tooth
structure would be the most beneficial.
The crown should encompass at least 2 mm past
the tooth core connection to achieve the most
protective ferrule effect.
19
20. • Sorensen & Engelman (1990) advised that as much coronal tooth as
possible should be preserved, and a butt-joint margin between the core
and tooth be used, i.e. minimal taper.
• Every effort should be made to save as much of the coronal tooth structure
as possible, because this helps reduce stress concentrations at the gingival
margin." The amount of remaining tooth structure is probably the single
most important predictor of clinical success.
• The presence of a 1.5- to 2-mm ferrule has a positive effect on fracture
resistance of endodontically treated teeth.
20
22. 2. Ferrule width
Esthetic restorations often
require fairly aggressive
preparations at the gingival
margin and sometimes buccal
defects such as abfraction may
compromise the buccal dentin
wall.
It has been accepted that the
walls are considered too thin
if they are less than 1 mm in
thickness, and would negate
the ferrule effect.
22
23. 3. No of walls and ferrule location
A circumferential ferrule would be optimal but caries may
affect the interproximal areas and abrasion or erosion the
buccal walls.
A crown preparation will further reduce the wall thickness
and only a partial ferrule will remain.
Ng et al said that good palatal ferrule is as effective as
having a complete “all around” ferrule.
Al-Wahadni and Gutteridge found having a 3 mm ferrule on
the buccal aspect was better than having no ferrule at all.
23
24. 4.Type of tooth and extent of lateral load
Anterior teeth are loaded non-axially.
Posterior teeth are loaded occluso-gingivally.
Anterior teeth with a deep overbite and parafunction are at a higher
risk of failure.
Teeth that are in group function with long maxillary buccal cusps
produce higher lateral forces than if there was canine guidance.
24
25. 5. Type of post
Cast posts have been used for many years for the support of the final restoration.
However, in recent years this type of restoration has been progressively
replaced by composite cores with a glass fiber post or metal post.
Fiber-reinforced posts have shown positive results as compared to metal
posts.
25
26. 6. Core materials
Composite resin with dentin bonding agent has frequently been
implicated as material that can strengthen the tooth and
reinforced cusps as compared to amalgam.
26
28. •Repairable fractures: above cemento-enamel junction (CEJ),
horizontal cervical fracture, core-tooth fracture.
•Non-repairable oblique fracture: entirely below CEJ, fracture in
the middle or apical third of the root, vertical root fracture.
Non repairable fractures are more common with cast dowel
post and 2mm ferrule
Reparable fractures are seen with fiber-reinforced posts
and 2mm ferrule.
Aggarwal, et al:Effect of ferrule on fracture resistance. Journal ofConservative
Dentistry ,2014;17(2):183-7
28
29. HOW TO CREATE FERRULE IN A
NO FERRULE CASE????
There are two methods:
1.Crown lengthening
2.Orthodontic extrusion
29
30. Effect of apical preparation on crown-to-root ratio.
A Schematic of extensively damaged premolar tooth. Apical extension of the gingival margin would encroach on the
biologic width.This preparation has no ferrule.
B Creating a ferrule with orthodontic extrusion reduces root length (R) while crown length (C) remains unchanged.
C Surgical crown lengthening also reduces root length (R) but increases crown length (C). This results in a much less
favorable crown-to-root ratio, which may not in fact strengthen the restoration.
Dr. A.G. Gegauff.
30
31. CLASSIFICATION OF FERRULE
Jotkowitz A:Rethinking Ferrule:a new approach to an old
dillemma.British Dental Journal,2010;209(1):25-33
31
Although current literature does not
present a uniform description and
design of the ideal ferrule, a
classification that is based on the
remaining tooth structure would be of
value.
32. Category A : No anticipatedrisk
Category B : Low risk
Category C : Medium risk
Category D : High risk
Category X : No ferrule
32
33. 33
Category A : No anticipatedrisk
Sound dentine walls remaining all aroundthe tooth, with height greater than 2mm and
with a minimum thickness of 1mm.
Such teeth do not present an anticipated risk for structural or mechanical failure
Category B : Low risk
Compromised or no ferrule present on either proximal surface. (ie less than 2mm height
and/or 1 mm thickness) OR two compromised proximal walls on a tooth that undergoes
light lateral loads.
Such teeth present low risk for structural or mechanical failure.
Category C : Medium risk
Two compromised proximal walls on a tooth that undergoes heavy lateral loads OR a
compromised buccal or lingual wall on a tooth that undergoes light lateral loads. Such
teeth present medium risk for structural or mechanical failure.
34. 34
Category D : High risk
A compromised buccal or lingual wall on a tooth that undergoes heavy lateral loads OR a
compromised buccal, and lingual wall on any tooth OR a tooth that has only two adjacent
walls or only a single wall remaining. Such teeth present high risk for structural or
mechanical failure and alternate treatment modalities should be considered and may be
more appropriate.
Category X : No ferrule
No ferrule can be established, such that the tooth is non-restorable. Actual treatment
rendered will be determined based on considering the entire dentition and attachment
apparatus, as well as individual patient risk factors and expectations.
36. Summary and Conclusion
◦ Based on the evidence from in vitro and in vivo studies reviewed, the presence
of ferrule has a positive effect on fracture resistance of endodontically treated
teeth.
◦ More successful prognosis could be expected if healthy dentin extending 1.5 to
2 mm coronal to the margin of the crown is provided circumferentially.
◦ If the clinical situation does not permit a 360 circumferential ferrule because of
extensive caries lesions, previous restorations, or fractures, an incomplete
ferrule is still considered a better option than complete absence of a ferrule.
◦ Moreover, including a ferrule in the preparation design could possibly lead to
more favourable fracture patters.
37
37. ◦ With regard to the effect of different restorative procedures on tooth resistance,
literature data are often controversial, probably because of the different
methodologies and study designs used.
◦ However, it could be generally concluded providing an adequate ferrule lowers
the impact of the post and core system, luting agents, and the final restoration
on the performance of endodontically restored teeth.
◦ When it comes to severely damaged teeth with no coronal structure, in order to
provide space for a ferrule, orthodontic extrusion should be considered rather
than surgical crown lengthening.
38
38. ◦ This approach preserves more tooth structure and ensures more favourable
biomechanical behaviour.
◦ If neither of the alternative methods for providing a ferrule can be performed,
currently available evidence suggests that poor treatment outcome is very
likely.
◦ Therefore, clinicians may take in consideration tooth extraction followed by
appropriate surgical and/or prosthetic rehabilitation.
39
39. References
◦ (Galen WW, Mueller KI: Restoration of the Endodontically Treated Tooth.
◦ In Cohen, S. Burns, RC, editors: Pathways of the Pulp, 10th Edition.)
◦ Jotkowitz A:Rethinking Ferrule:a new approach to an old dillemma.British Dental
Journal,2010;209(1):25-33
◦ RosenH:Operativeproceduresonmutilatedendodonticallytreatedteeth.J Prosthet Dent1961;11:973-986.
◦ SorensenJA,EngelmanMJ:Ferruledesignandfractureresistanceof endodonticallytreatedteeth.JProsthetDent
1990;63:529-536
◦ Trushkowsky RD:Restoration of endodontically treated teeth: Criteria and technique considerations.
Quintessence Int 2014;45:557–67
◦ Aggarwal,etal:Effectofferruleonfractureresistance.JournalofConservative Dentistry ,2014;17(2):183-7
◦ Jelena Juloski et al Ferrule Effect: A Literature Review JOE — Volume 38, Number 1, January 2012
40
Whether a tooth requires a post or not , is determined by the amount of remaining coronal tooth structure and the functional requirements.
Frequently the remaining tooth structure is not sufficient and a post is indicated to provide retaintion for the crown restoration.
It should be clear that the term ferrule is often misinterpreted. It is often used as an expression of the amount of remaining sound dentine above the finish line.
Posts are frequently used for the retention of a core material in teeth that have had extensive loss of coronal tooth structure.
Their use, however, may increase root fracture due to excessive pressures during insertion or because of lateral movement of the post within the root, thus ironically increasing the risk of root fracture and treatment failure.
Therefore, the use of a correct ferrule design is of particular importance in teeth restored with post and cores.
Ferrule design
If more than 2 mm of coronal tooth structure remains, the post design probably has a limited role in the fracture resistance of the restored tooth.
A classification of single rooted pulpless teeth based on the amount of remaining supra-gingival tooth structure has been recommended by Kurer in 1991 to aid with treatment planning of endodontic treated tooth.
This classification described five classes of pulpless teeth:
1 with sufficient coronal tissue for a crown,
2 requiring a core,
3 with no coronal tooth structure and
4 with deep fractures and
5 with periodontal complication respectively.
As suggested by Stankiewicz and Wilson the classification could be of more value if a subgroup were included that accounted for the presence of a minimal effective ferrule.