This document discusses factors to consider when selecting abutment teeth for fixed partial dentures (FPDs). It defines an abutment tooth and outlines how to assess potential abutments, including taking radiographs and evaluating crown morphology, root configuration, crown-to-root ratio, and other anatomical features. Good abutment teeth are vital with adequate bone and root support and crown structure to withstand forces from the FPD. Location, occlusion, tooth structure and root health must be optimized for successful force distribution from the prosthesis.
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.
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 presentation on the instructions to be given to complete denture patients at the insertion appointment. Dealing with patients can be hard at times but with a proper approach, a strong rapport can be formed with the patient.
Failures in Fixed Partial Denture
(Prosthodontics FPD- Dental science)
Various types of failures in the fabrication of fixed partial denture
Dr.Sachin Sunny Otta
St.Gregorios Dental College,Kothamangalam,Ernakulam
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.
A presentation on the instructions to be given to complete denture patients at the insertion appointment. Dealing with patients can be hard at times but with a proper approach, a strong rapport can be formed with the patient.
Failures in Fixed Partial Denture
(Prosthodontics FPD- Dental science)
Various types of failures in the fabrication of fixed partial denture
Dr.Sachin Sunny Otta
St.Gregorios Dental College,Kothamangalam,Ernakulam
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.
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.
Tooth preparation for full veneer crowns /certified fixed orthodontic course...Indian dental academy
The Indian Dental Academy is the Leader in
continuing dental education , training dentists
in all aspects of dentistry and offering a wide
range of dental certified courses in different
formats.
Indian dental academy provides dental crown &
Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit
www.indiandentalacademy.com ,or call
0091-9248678078
Dental Esthetics include the use of bonded ceramic veneers and laminates. This presentation helps to understand various concepts relating to the preparation and utility of such restorations. - Dr. Abhishek John Samuel, MDS (Endodontics)
Failures in fixed partial dentures /certified fixed orthodontic courses by In...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
This presentation describe the evaluation of badly damaged teeth for crowning before starting RCT treatment, because the treatment of such teeth is always achieved by crowning otherwise they will end for extraction. All the necessary procedures to save the damaged teeth are discussed in the context of restoring function, aesthetic and mechanical qualities. Evaluation of any case based on scientific data will insure durability and patient satisfaction.
Design of a fixed Partial Denture (with Abutment Tooth Preparation)Taseef Hasan Farook
A simplified take on the steps to designing a Fixed partial denture. This presentation also includes an overview of abutment preparation, associated finishes and methods of impression taking prior to the designing of the prosthesis itself
Overdentures are a useful treatment option in many clinical situations. A simple complete lower overdenture which encloses the roots of two root-treated canines has been shown above (Fig. 12.51). Cases can be more complicated than this. The reduction in the crowns of the teeth may have occurred due to tooth wear from a combination of erosion and attrition. In the elderly, where such tooth reduction has occurred, root canal treatment may not be necessary. The removal of the roots will not benefit the patient and the overdenture is the best form of treatment.
Less common situations, such as partial anodontia, cleft palate or loss of tooth crown substance in dentinogenesis imperfecta, may also require restoration using overdentures. The distinction between an onlay and an overdenture is not clear-cut and a potentially difficult partial denture treatment, such as the restoration of a free end saddle, may be helped by the coverage of a canine or molar tooth with a reduced crown rather than a more involved crown restoration.
In the case illustrated in Figure 12.53, an elderly patient has severe tooth surface loss. The aetiology of this wear must be diagnosed before treatment is commenced. For instance, is this wear a result of parafunction or erosion from the consumption of acidic drinks? The remaining dentition has been restored and a definitive overdenture placed.
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Abutment /certified fixed orthodontic courses by Indian dental academy Indian dental academy
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Description :
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Diagnosis and treatment planning in fixed partial denturesApurva Thampi
This gives an overview on the diagnostic and treatment planning procedures required in fixed partial dentures and also about the biomechanics involved in the selection of an appropriate fixed prosthesis.
The presentation can be available upon request. Mail me at apurvathampi@gmail.com
Similar to Abutment & Its Selection In Fixed Partial Denture (20)
One of the best seminar of the author. Covered in detail regarding the increasing vertical dimension, centric relation, methods to record centric relation, philosophies of occlusion and in detail everything about full mouth rehabilitation.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
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Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
1. Abutment & Its Selection In
FPD
Guided By:-
Dr. Dilip Dhamankar (HOD)
Dr. Ravi Kumar C.M. (Prof.)
Dr. Meenaksi (Prof.)
Dr. DRV Kumar (Reader)
Dr. Arun (Reader)
Dr. Manish Chadha (Senior
Lect.)
Dr. Devendra (Senior Lect.)
Dr. Mayank (Senior Lect.)
Dr. Soham Prajapati
2nd Year PG,
Dept. of Prosthodontics
& Maxillofacial Prosthesis
Including Oral Implantology
22-11-14
1/135
2. Contents
• Introduction
• Definition
• Assessment of abutment teeth
• Criteria of selection
• Factors governing abutment selection
Crown
Crown to root ratio
Root configuration
Root surface area
• Biomechanical Consideration
– Length of span
– Height of connector
– Double abutment
Abutment & Its Selection In FPD 2/135
3. Contents
• Types of Abutment
– Questionable Abutment
– Pier Abutments
– Cantilever Fixed Dental Prosthesis
– Spring Cantilever Abutment
– Tilted Molar Abutments
– Canine replacement FDP
– Splinted Abutments
Conclusion
References
3/135Abutment & Its Selection In FPD
4. Introduction
• Every restoration must be able to withstand the
constant occlusal forces to which it is subjected &
this is of particular significance when designing &
fabricating a fixed dental prosthesis.
• All the forces that would normally be absorbed
by the missing tooth are transmitted, through the
pontic, connectors, & retainers to abutment
teeth.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. 3rd ed. Chicago: Quintessence; 1997.p. 85-103.
4/135Abutment & Its Selection In FPD
5. Introduction
• Abutment teeth therefore withstand forces
normally directed to the missing teeth, in
addition to those usually applied to the
abutments, so the clinician must evaluate the
abutment teeth carefully.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. 3rd ed. Chicago: Quintessence; 1997.p. 85-103.
5/135Abutment & Its Selection In FPD
6. Definition
• Fixed Partial Denture
– A partial denture that is luted or otherwise securely
retained to natural teeth, tooth roots, and/or
dental implant abutments that furnish the primary
support for the prosthesis.
6/135Abutment & Its Selection In FPD
The Glossary of Prosthodontic Terms, 8th Edition J Prosthet Dent 2005;81:63.
7. Definition
ABUTMENT –
That part of a structure that directly receives
thrust or pressure; an anchorage .
Or
A tooth, a portion of a tooth, or that portion of a
dental implant that serves to support and/or
retain a prosthesis .
Abutment & Its Selection In FPD 7/135
The Glossary of Prosthodontic Terms, 8th Edition J Prosthet Dent 2005;81:63.
8. Assessment of Abutment Teeth
• Considerable time and expense are spared, and
loss of a patient’s confidence can be avoided, by
thoroughly investigating each abutment tooth
before proceeding with tooth preparation.
• Radiographs are made, & pulpal health is
assessed by evaluating the response to thermal &
electrical stimulation.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. 3rd ed. Chicago: Quintessence; 1997.p. 85-103.
Abutment & Its Selection In FPD 8/135
9. Number and Type of Radiographs
Needed.
• 1 OPG
• If no periapical lesions are present,
– 4 Bitewings Radiographs [2 with each quadrant
(one for premolars and one for molars)]
– 4 IOPA Radiographs (1 for each quadrant covering
incisors and canine)
• If periapical lesions are present,
– 12 IOPA Radiographs
– 2 Occlusal Radiographs
9/135Abutment & Its Selection In FPD
10. • The primary purpose of roentgenograms is to
disclose hidden areas and structures such as
– Root length and morphology
– Pulp outline
– Periodontal ligament space
– Alveolar bone
– Infrabony defects
– residual roots
– impacted or supernumerary teeth
– The extent of present or past caries
– Evaluate root canal filling
Assessment of Abutment Teeth
10/135Abutment & Its Selection In FPD
11. • Existing restorations, cavity liners, & residual
caries are removed & a careful check is made
for possible pulpal exposure.
• In younger adults generally the pulp horns are
high & broad, but as age progresses there is
receding of the pulp horns & also sometimes
calcification occurs
Assessment of Abutment Teeth
11/135Abutment & Its Selection In FPD
12. • But when the tooth is non- vital due to reasons like trauma,
periapical pathology, endodontic treatment will have to be
carried out followed by restoration.
Assessment of Abutment Teeth
12/135Abutment & Its Selection In FPD
13. • The supporting tissues surrounding the abutment teeth must
be healthy & free from inflammation before any prosthesis
can be contemplated.
• The abutment teeth should not exhibit any mobility, since
they will be carrying an extra load.
Assessment of Abutment Teeth
13/135Abutment & Its Selection In FPD
14. Assessment of Abutment Teeth
• Diagnostic Cast
– Dimension of edentulous space.
– Occlusal plane
– Final outcome of propose treatment through
‘diagnositic waxing’
V Rangarajan, Textbook Of Prosthodontics, pg 470
14/135Abutment & Its Selection In FPD
15. Assessment of Abutment Teeth
• Diagnostic Cast
– Rotated and malposed teeth can be easily
observed. The form and contour of prospective
abutment teeth and the gingival tissues can be
visualized as well as the alignment and contacts of
opposing teeth.
Reynolds JM. Abutment selection for fixed prosthodontics. J Prosthet Dent 1968;19:483-8.
15/135Abutment & Its Selection In FPD
18. LOCATION, POSITION & CONDITION
• Teeth with the following characteristics are
preferred abutments:
– Teeth adjacent to edentulous spaces.
– Teeth with grossly decayed crown that can be
restored with a full veneer crown. (periodontal
support should be uncompromised.)
18/135Abutment & Its Selection In FPD
19. LOCATION, POSITION & CONDITION
– Modifications like dowel core and pin retained
amalgam restorations may be needed to restore
crown morphology in grossly destructed teeth.
– Vital teeth are preferred, though endodontic
treated teeth can be used.
– Pulp capped teeth should be avoided because
they are under the risk of requiring RCT.
19/135Abutment & Its Selection In FPD
22. SHAPE
22/135Abutment & Its Selection In FPD
• Some teeth have tapered crown form that interferes with
the preparation parallelism, necessitating full coverage
crowns to improve esthetics and retention.
• Examples:
• Peg laterals
• Anterior teeth with poorly developed cingula and short
proximal walls
• Mandibular premolars with poorly developed lingual
cusps and short proximal surfaces
• Thin incisors.
23. Bulbous form Tapered form
Peg form Conical form
SHAPE
23/135Abutment & Its Selection In FPD
24. CROWN LENGTH
• The abutment teeth must have adequate occlusocervical
crown length to achieve sufficient retention.
• Full coverage restorations and crown lengthening are
considered with short clinical crowns to ensure adequate
retention.
Long Crown Short Crown
24/135Abutment & Its Selection In FPD
25. DEGREEOF MUTILATIONOF CROWN
25/135Abutment & Its Selection In FPD
• The size, number and location of carious lesions or
restorations in a tooth will influence the type of retainer on
an abutment.
• If the mutilation/fracture is severe, removal of that tooth is
necessary which will alter the design of the original
prosthesis.
26. Abutment & Its Selection In FPD
• The size, number and location of carious lesions or
restorations in a tooth will influence the type of retainer on
an abutment.
• If the mutilation/fracture is severe, removal of that tooth is
necessary which will alter the design of the original
prosthesis.
• For such tooth, PRINCIPLE OF SUBSTITUTION should be
followed.
DEGREEOF MUTILATIONOF CROWN
26/135
27. OCCLUSAL ANATOMY
• Has an indirect influence on the loads transmitted.
• The ridges and grooves increase the sharpness and
shearing action of teeth and reduce friction between
opposing surfaces by keeping the contacting area to a
minimum.
• This permits the most efficient mastication of food,
thus reducing the load transmitted.
• According to Stallard, worn-down teeth need more
muscular power and longer and more masticatory
strokes in order to chew food enough .
Reynolds JM. Abutment selection for fixed prosthodontics. J Prosthet Dent 1968;19:483-8.
27/135Abutment & Its Selection In FPD
28. BUCCOLINGUAL DIMENSION
The Occlusal surface of pontics should harmonize
with buccolingual dimension of natural
unmutilated teeth, and recreate the normal
buccal and lingual form to the height of contour.
Reducing the width of the pontics does not
materially reduce the forces transmitted to the
abutments, but merely places heavier per unit
stress on the restoration and produces conditions
in the pontic similar to those of malposed and
improperly contoured teeth.
Reynolds JM. Abutment selection for fixed prosthodontics. J Prosthet Dent 1968;19:483-8.
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29. MESIODISTALDIMENSION
• The total mesiodistal width of the cusps of
abutments should equal or exceed the width
of the cusps of pontics.
• The is relationship assures that the occlusal
load transmitted to the abutment teeth will
not be more than twice the amount normally
supported by these teeth individually.
Reynolds JM. Abutment selection for fixed prosthodontics. J Prosthet Dent 1968;19:483-8.
29/135Abutment & Its Selection In FPD
30. MESIODISTALDIMENSION
• Most healthy
organs of the body
are considered to
have a reserve
capacity equal, at
least, to their
normal functional
requirements.
Reynolds JM. Abutment selection for fixed prosthodontics. J Prosthet Dent 1968;19:483-8.
30/135Abutment & Its Selection In FPD
31. The shape of the roots also determines the ability
of the root to handle occlusal forces.
Teeth with a wider buccolingual
dimension than mesiodistal have
a greater ability to handle load
than conically shaped roots.
Multi-rooted teeth with separated roots
are better at displacing occlusal load than
teeth with conjoined roots.
31/135Abutment & Its Selection In FPD
Root Configuration
32. • The tooth with conical roots can be used as an abutment
for a short span fixed partial denture if all the other
factors are optimal.
• Teeth with longer root are stronger abutment than
compared to shorter ones.
• A single rooted tooth with evidence of irregular
configuration or with some curvature in the apical third
of the root is preferable to the tooth that has a nearly
perfect taper.
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. 3rd ed. Chicago: Quintessence; 1997.p. 85-103.
32/135Abutment & Its Selection In FPD
Root Configuration
33. • The length of the abutment root is directly proportional
to the stability and strength of the prosthesis.
• Stability : The quality of a prosthesis to be firm, steady,
or constant, to resist displacement by functional
horizontal or rotational stresses
33/135Abutment & Its Selection In FPD
Root Configuration
V Rangarajan, Textbook Of Prosthodontics, pg 470
The Glossary of Prosthodontic Terms, 8th Edition J Prosthet Dent 2005;81:63.
34. • Because of the conical shape of most roots, the actual
area of support (A) diminishes more than might be
expected from the height of bone (H). In addition, the
centre of rotation (R) moves more apical (R’) and the
lever arm (L’) increases, magnifying the forces on the
supportive structure.
34/135Abutment & Its Selection In FPD
Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics. 3rd ed. St. Louis:
Elsevier; 2000. p. 46-64.
35. Root Proximity
• Must be adequate clearance between the
roots of proposed abutments to permit the
development of physiologic embrasures in the
complete prosthesis.
• Malpositioned anterior teeth and mesiobuccal
roots of maxillary molars often present
unfavourable root proximities.
• Selective extraction or root resection
procedures may be the only solution.
V Rangarajan, Textbook Of Prosthodontics, pg 470
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36. Abutment Evaluation
• Crown-to-Root Ratio
– Ideally, a clinical crown-to-root
ratio of 2:3 is sought after.
Minimally, we’d like to see a 1:1
for a tooth to be considered for
use as an abutment.
– This ratio is determined by a
comparison of the linear
measurement of the portion of
the tooth above the bone to that
within the bone.
Reynolds JM. Abutment selection for fixed prosthodontics. J Prosthet Dent 1968;19:483-8.
36/135Abutment & Its Selection In FPD
37. Abutment Evaluation
• Crown-to-Root Ratio
– Hence for the same reason, an abutment teeth with a less
than desirable crown-root ratio is more likely to successfully
support a FPD if
• Opposing Occlusion is a Removable Prosthesis
• Opposing Periodontally Weak teeth
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. 3rd ed. Chicago: Quintessence; 1997.p. 85-103.
37/135Abutment & Its Selection In FPD
V Rangarajan, Textbook Of Prosthodontics, pg 470
Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics. 3rd ed. St. Louis:
Elsevier; 2000. p. 46-64.
38. Abutment Evaluation
• Crown-to-Root Ratio
– Force exerted on FPD depend the opposing dentition,
muscular activity of the patient and parafunctional habits.
– Average values of force exerted against a fixed prosthesis
• RPD – 26 lb
• FPD – 54.5 lb
• Natural teeth 150 lb
Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE. Fundamentals of fixed
prosthodontics. 3rd ed. Chicago: Quintessence; 1997.p. 85-103.
38/135Abutment & Its Selection In FPD
39. Some Facts
– The mean duration of the chewing cycle during which the
teeth are subjected to occlusal forces was 240 ms.
– Masticatory force generated
• Natural dentition -- 120-180 lb
• CD -- 16-22 lb
• RPD -- 22-28 lb
• FPD -- 50-65 lb
• Implant-supported -- 10-100 lb
complete dentures
39/135Abutment & Its Selection In FPD
S Gowri Shankar, Dentest Clinical Sciences, 5th edition, pg 1016
Lundgren D, Laurell L., Occlusal force pattern during chewing and biting in dentitions
restored with fixed bridges of cross extension, J Oral Rehabil. 1986 Jan; 13(1):57-71
40. • Periodontal Ligament Area
– The periodontal ligament area can be used as a
scale or measurement to determine the potency of
an abutment.
– Tylman stated that the two abutment teeth could
support two pontics.
– Johnston et al improvised Tylman’s Statement amd
proposed the famous ANTE’s Law.
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Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed prosthodontics. 3rd ed. St. Louis:
Elsevier; 2000. p. 46-64.
41. • Periodontal Surface Area (Ante’s Law)
– “The combined pericemental area of the
abutment teeth should be equal to or greater in
pericemental area than the teeth to be replaced”.
– In cases where the periodontal surface area seems
inadequate, the use of multiple teeth for
abutments may be indicated depending on other
biomechanical factors.
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42. The combined root surface area of the second
premolar and the second molar (A2p+A2m) is
greater than that of the first molar being
replaced (A1m).
The combined root surface area of the first
premolar and the second molar abutment
(A1p+A2m) is approximately equal to that of the
teeth being replaced (A2p+A1m)
The combined root surface area of the canine
and the second molar (Ac+A2m) is exceeded by
that of the teeth being replaced (A1p+A2p+A1m
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43. • Jespen (1963) has reported average measurements of
root surface areas that can be used to calculate the
abutment to pontic ratio.
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44. Abutment Evaluation
• Periodontal Surface Area (Ante’s Law)
Order of Abutments concerning
Periodontal Surface Area:
• First Molar
• Second Molar
• Canine
• First Premolar
• Second Premolar
• Central Incisor
• Lateral Incisor
Maxillary Arch
44/135Abutment & Its Selection In FPD
45. Abutment Evaluation
• Periodontal Surface Area (Ante’s Law)
Order of Abutments
concerning Periodontal
Surface Area:
• First Molar
• Second Molar
• Canine
• Second Premolar
• First Premolar
• Lateral Incisor
• Central Incisor
Mandibular ArchMandibular Arch
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46. • It has been shown that provided periodontal disease is
treated , periodontal health maintained and occlusal
forces evenly distributed, FPD can be successful with as
little as ¼ of the support advocated by Ante.
• Hence, Ante’s Law is a safe and useful guideline for
abutment selection, when employed with other factors
involved in evaluating abutment capabilities.
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47. LONG AXIS RELATIONSHIP
o The long axis relationship of
abutment teeth should be no
more than 25- 30 degree from
the parallel.
oForces are withstood best
when they are directed along
the long axis of the tooth.
47/135Abutment & Its Selection In FPD
48. o A severely inclined tooth will
not withstand forces as well
as one that is erect.
o Abutment teeth in an FPD
must be prepared with a
common path of insertion for
all retainers when rigid design
is employed.
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49. ARCHCURVATURE
When pontics lie outside the interabutment axis line,
the pontics act as a lever arm, which can produce a
torquing movement.
This is a common problem in replacing all four maxillary
incisors with a fixed partial denture.
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50. This can best be accomplished by gaining additional
retention in the opposite direction from the lever
arm and at a distance from the interabutment axis
equal to the length of the lever arm.
The first premolars sometimes are used as secondary
abutments for a maxillary four-pontic canine-to-
canine fixed partial denture
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52. PERIODONTALFACTOR
• Abutment teeth must be
free from
– periodontal diseases,
periodontal pockets,
– osseous defects,
– gingival inflammation,
– and must have an
adequate zone of
attached gingiva.
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53. PERIODONTALFACTOR
• Biologic width is the distance established by the “junctional
epithelium and connective tissue attachment to the root
surface” of a tooth
• Mean Biologic width – 2.04mm
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54. • To avoid encroaching on the biologic width, the tooth
preparation must terminate at least 2mm coronal to
the alveolar crest.
• The presence of caries, fractured root structure, or
previous restorations apical to the gingival crest in
abutment teeth may predispose to violation of biologic
width during tooth preparation.
• A short clinical crown may induce the dentist to
overextend the preparation apically in an attempt to
enhance retention.
54/135Abutment & Its Selection In FPD
56. Tooth Form
• Two methods of modifying the tooth form to
change the unfavorable crown to root ratio.
– Construction of complete crown.
– Change the occlusal surface of the tooth with an
onlay.
Malone WFP, Koth DL. Tylman’s theory and practice of fixed prosthodontics. 8th ed. St. Louis:
Ishiyaku EuroAmerica; 1989. p. 67-8.
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57. Tooth Form
– Change the occlusal surface of the tooth with an
onlay.
• Lateral and tipping stresses arise during function when
the cuspal inclines are steep or the occlusal topography
is too broad.
• Ideally, forces applied to the tooth fall within the
periphery of the root structure in bone.
• In mandible, this force is transmitted to the root by the
buccal cusps.
Malone WFP, Koth DL. Tylman’s theory and practice of fixed prosthodontics. 8th ed. St. Louis:
Ishiyaku EuroAmerica; 1989. p. 67-8.
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58. Tooth Form
• Hence, the location of the cusp in relation to the roots
in the buccolingual direction influences the direction of
the trasmitted force upon periodontium.
• If the direction of the functional forces fall within the
lateral borders of the clinical root, stress is directed
vertically upon the periodontium.
• If the force is directed beyond the confines of the root,
tipping stresses are induced.
Malone WFP, Koth DL. Tylman’s theory and practice of fixed prosthodontics. 8th ed. St. Louis:
Ishiyaku EuroAmerica; 1989. p. 67-8.
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59. Tooth Form
• Narrowing the buccolingual width of the occlusal
surfaces of the reconstructed crowns encourages a
more desirable location for the mandibular buccal and
maxillary palatal cusps in relation to the root.
Malone WFP, Koth DL. Tylman’s theory and practice of fixed prosthodontics. 8th ed. St. Louis:
Ishiyaku EuroAmerica; 1989. p. 67-8.
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60. Biomechanical Considerations
• Management of Destructive Forces
– The design of the bridge should allow for occlusal
forces and dislodging forces, like torque, flexure,
and tension to be handled.
– Occlusion should be designed to optimize the
distribution of occlusal forces evenly throughout
the envelope of motion over the entire mouth.
60/135Abutment & Its Selection In FPD
62. • Length of Span
(Law of Beams)
– The Law of Beams is an
engineering principle
that states that as the
length of the span
increases, the flexure of
a system will be the
increase in length to the
power of three (cubed).
62/135Abutment & Its Selection In FPD
63. Therefore, doubling the length would yield 8 times
the flexure. Tripling the length would yield 27 times
the flexure.
63/135Abutment & Its Selection In FPD
64. • Height of Connector (Law of Beams)
– As the height of the span decreases, the
flexure of a system will be the increase in
length to the power of three (cubed).
– Therefore, halving the connector height would
yield 8 times the flexure. A connector only 1/3
as tall would yield 27 times the flexure.
64/135Abutment & Its Selection In FPD
65. Double Abutment
• This refers to the use of two adjacent teeth at
one or both ends of the FPD as abutments.
65/135Abutment & Its Selection In FPD
66. Double Abutment
• The abubtment adjacent to edentulous space
is termed as primary abutment and the
adjacent abutment is termed as secondary
abutment.
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67. Double Abutment
• Indications:
– To increase retention of restoration.
– To increase area of supporting periodontal
ligament and bone.
– Unfavourable crown-root ratio.
– Long span FPDs
– Spint and stabilize periodontal compromised
teeth.
67/135Abutment & Its Selection In FPD
68. Double Abutment
• Secondary abutment must meet the following
criteria:
– It must have as much root surface area, as
favorable a crown root ratio and similar retention
as the primary abutment.
– Sufficient crown length and space should be
present between the adjacent abutments to
prevent impingement of the gingiva under the
connector.
68/135Abutment & Its Selection In FPD
70. Questionable Abutment
• Definition
– A common dilemma especially when the
abutment is periodontally involved, partially
fractured, polycarious or in poor arch position.
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72. • Disturbances In Size of Teeth
– Microdontia
– Macrodontia
• Disturbances in Number of Teeth
– Anodontia (Complete or Partial)
– Supernumerary Teeth
Swapan Kumar Purkait. Essentials of Oral
Pathology, 2nd Edition, 235-250.
72/135Abutment & Its Selection In FPD
74. CROWN AND ROOT
– Gemination (Twinning)
• Developmental anamaly, which refers to the partial
development of two teeth from a single tooth bud
following incomplete division.
• Twinning refers to the complete and equal division of a
single tooth germ that result in the formation of one
normal and one supernumerary tooth.
• Deciduous mandibular incisor and permanent
maxillary incisors.
Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition, 235-250.
74/135Abutment & Its Selection In FPD
75. CROWN AND ROOT
– Fusion
• Union of two adjacent normal tooth germs at the level
of dentin during development.
• Fusion results in one anomalous large crown in place of
two normal teeth and is having a single enlarged root
or two roots.
• In both dentition and the incisors are frequently
invloved.
Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition, 235-250.
75/135Abutment & Its Selection In FPD
76. • CROWN
– Dens-Evaginatus
• Developmental anomaly of tooth in which a focal area
of the crown projects outward and gives rise to Globe
shaped protruberence on the occlusal surface, which
appears as an extra cusp.
• Does not enounter any problem. Can be used as
abutment.
Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition, 235-250.
76/135Abutment & Its Selection In FPD
77. ROOT
• Concrenscence
• Union of the roots or two or more adjoining teeth due
to deposition of cementum is known as concrescence.
• Acquired defect (erupted or unerupted).
• Permanent maxillary molars
Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition, 235-250.
77/135Abutment & Its Selection In FPD
78. • Root
– Dilaceration
• Refers to the angulation or a sharp bend or a curve
anywhere along the root portion of a tooth.
• Best as abutment tooth
• Seen in both dentition with any tooth.
Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition, 235-250.
78/135Abutment & Its Selection In FPD
79. • CROWN, ROOT & PULP
– Dens-In-Dente (Tooth Within a Tooth)
• A defect in the morphologic of tooth in which a focal
area on the tooth surface is folded or invaginated
pulpally to a variable extend.
• Maxillary Lateral Incisor.
Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition, 235-250.
79/135Abutment & Its Selection In FPD
80. • DISTURBANCES IN THE STRUCTURE OF TEETH
80/135Abutment & Its Selection In FPD
81. • Enamel
– Amelogenesis imperfecta (hereditary)
– Focal enamel hypoplasia (local factors)
– Acquired
• Nutritional deficiency (vitamin a, c & d)
• Congenital syphilis
• Fluorides
Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition, 235-250.
81/135Abutment & Its Selection In FPD
84. Carious Teeth
• Determine its amount and distribution.
• Polycarious – usually susceptible to recurrent
caries.
• Full coverage crowns after removal of carious
part and restoring it
• Caries Control Program
– Prophylaxis ----- Fluoride treatment
– Dietary consultation
– Restoration
84/135Abutment & Its Selection In FPD
85. Carious Teeth
Caries Control Program
– Endo-Perio consultation
– Cast metal restoration after amalgam restoration
– Recall system strictly maintained.
85/135Abutment & Its Selection In FPD
86. Periodontally Involved teeth
Prior to or concomitant carious control program.
- Excessive mobility – no FPD.
- Splinting may be tried.
Treatment
- Early interception
- elimination of those periodontally involved
teeth beyond the dignity of a restoration.
86/135Abutment & Its Selection In FPD
87. Periodontally Involved teeth
Treatment
- Termination of finishing line at or above the
soft tissue(except for esthetics and retention).
- quadrant splinting if and when single units
are impossible.
- telescopic type full arch splinting for
terminal cases.
87/135Abutment & Its Selection In FPD
88. • Disadvantage of Splinting
– Severely limits ability to perform oral hygiene
procedures.
– Crucial decision – especially sound terminal
abutment to stabilize healthy teeth.
88/135Abutment & Its Selection In FPD
89. Resected Teeth
• Clinical evidence shows selected usage is
acceptable.
• Surgery should be so performed that cleanable
gingival termination is possible.
• Bicuspid/molars are most suitable.
• Resected maxillary molars- use only if it’s a must-
as a pier abutment.
• Patient should be informed of the risk and the
dentist must be confident to do the procedure.
89/135Abutment & Its Selection In FPD
90. Resected Teeth
• Treatment
– Core and Dowel
– Crown and contour to prevent tissue stagnation.
– Splinting
90/135Abutment & Its Selection In FPD
91. Attrition and Abrasion
• Short teeth
• Problem encountered are:-
– Vertical height is less so less retention.
– FPD may not be possible.
– Plan out for Overdentures or Telescopic Crown.
91/135Abutment & Its Selection In FPD
92. Eroded Teeth
• The gingival finish line is placed beyond the
eroded area/ restoration.
• It arrests the process.
• Has the pulpal recession proceeded at the
same rate as erosion – not usually related.
• If bone support is adequate – restoration and
full coverage are usually recommended.
92/135Abutment & Its Selection In FPD
93. Pier Abutment/Intermediate Abutment
• It is a natural tooth located
between terminal
abutments that serve to
support a fixed or
removable prosthesis.
• Because they lie in the
middle of the span, they can
act as a fulcrum for
destructive forces.
93/135Abutment & Its Selection In FPD
94. • A common clinical situation , either in maxillary or
mandibular arch is of missing first premolar & first
molar, resulting in FDP design where –
First premolar & first molar are terminal abutments
& second premolar serves as a pier abutment.
94/135Abutment & Its Selection In FPD
95. • Parfitt GJ (1960), have shown that the faciolingual
movement ranges between 56-108 µm, and intrusion of
28 µm. Teeth in different segments of the arch move in
different directions. Because of the curvature of the
arch, the faciolingual movement of an anterior tooth
occurs at a considerable angle to the faciolingual
movement of molar.
95/135Abutment & Its Selection In FPD
96. • These movements of measurable magnitude and in
divergent directions can create stresses in a long span
prosthesis that will be transferred to the abutments.
• Because of the distance through which it occurs, the
independent direction and magnitude of movements of
the abutment teeth, and the tendency of the prosthesis
to flex, stress can be concentrated around the
abutment teeth as well as between retainers and
abutment preparations.
96/135Abutment & Its Selection In FPD
97. • It has been postulated that the tendency of the
terminal abutments to intrude during function results
in a teetering movement, where the pier acts as a
fulcrum.
• This movement will eventually result in debonding of
the less retentive terminal retainer i.e canine &
inevitably the failure of the prosthesis.
97/135Abutment & Its Selection In FPD
98. • In order to overcome this potential risk, the use of
non-rigid connector has been advised.
• Shillinburg et al ( 1973 ) determined that the patrix of
non-rigid connector ( either a precision or
semiprecision attachment) should be placed at the
distal aspect of the pier retainer & matrix in the distal
pontic.
98/135Abutment & Its Selection In FPD
99. Precision Attachment
• Synonym : Parallel Attachment
• a retainer consisting of a metal receptacle
(matrix) and a closely fitting part (patrix); the
matrix is usually contained within the normal
or expanded contours of the crown on the
abutment tooth and the patrix is attached to a
pontic or the removable partial denture
framework
---- GPT, 8th Edition
99/135Abutment & Its Selection In FPD
100. SemiPrecision Attachment
• Synonym : Semiprecision rest
• A rigid metallic extension of a fixed or
removable partial denture that fits into an
intracoronal preparation in a cast restoration
---- GPT, 8th Edition
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101. • He assumed that this would nullify the fulcrum effect,
& that the matrix portion of the attachment would be
seated firmly in place when pressure was applied
distally to the pier, due to mesial movement of distal
abutment.
101/135Abutment & Its Selection In FPD
102. • Markley (1951) suggested that non-rigid connector
should be placed on one of the terminal retainers, &
emphasized that it should not be placed at the pier
abutment because this would subject the relatively
weak premolar abutment to the extreme loads.
• Gill (1952) recommended placing non-rigid connectors
at one side or both sides of pier abutment.
• Adams ( 1956) advised placing one non-rigid connector
at the distal side of the pier, & if desired adding one
more at the distal of the anterior retainer.
102/135Abutment & Its Selection In FPD
103. • However use of non-rigid connector in a posterior 5
unit FDP with a pier is contraindicated in some
situations ( SCHILLINBURG ET AL )
Abutment teeth with significant mobility.
Span between abutments is longer than 1 tooth.
If the distal retainer & pontic are opposed by a
removable partial denture or an edentulous ridge,
while the 2 anterior retainers are opposed by
natural dentition, possibly allowing the distal
terminal abutment to supraerupt.
103/135Abutment & Its Selection In FPD
104. Cantilever Fixed Dental Prosthesis
• Terms Used are:- Swing On or free-end
• A fixed dental prosthesis in which the pontic is
cantilevered i.e. is retained and supported only on one
end by one or more abutments ( GPT-8)
Joseph E. Ewing, Fixed Parial Prosthesis, 2nd Edition, 270.
104/135Abutment & Its Selection In FPD
105. Cantilever Fixed Dental Prosthesis
• Long term prognosis of single abutment cantilever is
poor.
• Forces applied to a cantilever FDP are resisted on only
one side, leading to imbalance.
• Endodontic treated tooth are contraindicated as
abutment.
105/135Abutment & Its Selection In FPD
106. • Vertical forces can cause tipping,
and horizontal forces, rotation of
abutment teeth.
• A Cantilever induces lateral forces
on the supporting tissues, which
may be harmful and lead to tipping,
rotation, or drifting of the
abutment.
106/135Abutment & Its Selection In FPD
107. • Prospective abutment teeth for cantilever FDP should
be evaluated with an eye toward lengthy roots with a
favourable configuration, long clinical crowns, good
crown-root ratio, & healthy peridontium.
• Generally, a cantilever should replace only one tooth &
have atleast two abutments.
107/135Abutment & Its Selection In FPD
109. • Rigid bridge design is always preferred for
cantilever principle.
• Cantilever principle when properly applied,
will serve as an excellent compromise to meet
clinical conditions.
Joseph E. Ewing, Fixed Parial Prosthesis, 2nd Edition, 270.
109/135Abutment & Its Selection In FPD
110. SPRINGCANTILEVER ABUTMENT
• Abutment is not located
adjacent to edentulous
space and pontic recieves
support from one side only.
• A posterior abutment,
generally, premolar is used
to replace an anterior tooth
and a bar is used to connect
the abutment and pontic.
110/135Abutment & Its Selection In FPD
111. SPRINGCANTILEVER ABUTMENT
• Indication
– Replacement of missing central incisor when diastema is to
be maintained.
• Contraindication
– Mandibular arch as bar causes tongue interferences.
• Disadvantages
– Bar interferes with speech and can cause food entrapment.
111/135Abutment & Its Selection In FPD
112. TILTED MOLAR ABUTMENTS
Loss of permanent mandibular
first molars to caries early in life
is still relatively common.
If this space is ignored, the
second molar will tilt mesially
with eruption of the third molar.
112/135Abutment & Its Selection In FPD
113. • It then becomes difficult or impossible to make a
satisfactory FDP, because the positional relationship
no longer allows for parallel paths of insertion with
out interferences from adjacent teeth.
113/135Abutment & Its Selection In FPD
114. Treatment Options
PROXIMAL HALF CROWN ON MOLAR
ORTHODONTIC TREATMENT –
Uprighting the tilted molar
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115. TELESCOPIC CROWN & COPING NONRIGID CONNECTOR
115/135Abutment & Its Selection In FPD
116. Canine replacement fixed partial dentures
• Fixed partial dentures replacing canines can be
difficult because the canine often lies outside the
interabutment axis.
• The prospective abutments are the lateral incisors,
usually the weakest tooth in the entire arch, and the
premolar, the weakest posterior tooth.
116/135Abutment & Its Selection In FPD
117. • A fixed partial denture replacing a
maxillary canine is subjected to more
stresses than that replacing a
mandibular canine, since forces are
transmitted outward (labially) on the
maxillary arch, against the inside of the
curve (its weakest point).
• On the mandibular canine, the forces
are directed inward (lingually), against
the outside of the curve (its strongest
point)..
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118. SPILNTED ABUTMENT
It is the abutment which is used in addition to the
primary abutments in case of a long edentulous span, or
if the primary abutment is weak.
118/135Abutment & Its Selection In FPD
119. SPILNTED ABUTMENT
Splinting is done by:-
- Splinting by Bonding (Composite)
- Provisional splinting with full coverage acrylics.
Malone WFP, Koth DL. Tylman’s theory and practice of fixed prosthodontics. 8th ed. St. Louis:
Ishiyaku EuroAmerica; 1989. p. 67-8.
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120. SPILNTED ABUTMENT
Splinting is done by:-
- Experience has shown that splinting can create more
problems than it solves.
-Splinting is arduous, expensive and time
consuming, the completed restoration is difficult for
the patient to clean.
Malone WFP, Koth DL. Tylman’s theory and practice of fixed prosthodontics. 8th ed. St. Louis:
Ishiyaku EuroAmerica; 1989. p. 67-8.
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121. • Conditions where increase in number of abutments is
considered ( TYLMAN )
Bone loss from periodontal disease.
Mesial or distal tipping or changes in axial inclination.
Less than favourable opposing arch relationships
producing increased occlusal load.
Endodontically restored abutment teeth with root
resections.
Arch form situations creating greater leverage factors.
Tooth mobility created after osseous surgery.
Malone WFP, Koth DL. Tylman’s theory and practice of fixed prosthodontics. 8th ed. St. Louis:
Ishiyaku EuroAmerica; 1989. p. 67-8.
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123. • Every restoration must be able to withstand the constant
occlusal forces to which it is subjected. This of a
particular significance when designing and fabricating a
FPD.
• Since the forces that would normally be absorbed by the
missing teeth are transmitted through pontic, connectors
and retainers to the abutment tooth.
• If success is to be attained, the prosthodontist must take
into account the abutment mobility, alveolar bone
support, root configuration and angulation, opposing
occlusion, pulpal condition, presence of endodontic
treatment, and the remaining tooth structure.
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124. REFERENCES
• Rosenstiel SF, Land MF, Fujimoto J. Contemporary fixed
prosthodontics. 3rd ed. St. Louis: Elsevier; 2000. p. 46-64.
• Shillingburg HT, Hobo S, Whitsett LD, Jacobi R, Brackett SE.
Fundamentals of fixed prosthodontics. 3rd ed. Chicago:
Quintessence; 1997.p. 85-103, 191-2.
• Malone WFP, Koth DL. Tylman’s theory and practice of fixed
prosthodontics. 8th ed. St. Louis: Ishiyaku EuroAmerica; 1989. p.
67-8.
• Swapan Kumar Purkait. Essentials of Oral Pathology, 2nd Edition,
235-250.
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125. REFERENCES
• S Gowri Shankar, Dentest Clinical Sciences, 5th edition, pg 1016
• V Rangarajan, Textbook Of Prosthodontics, pg 470
• Joseph E. Ewing, Fixed Parial Prosthesis, 2nd Edition, 14-20.
• The Glossary of Prosthodontic Terms, 8th Edition J Prosthet Dent
2005;81:63.
• Reynolds JM. Abutment selection for fixed prosthodontics. J
Prosthet Dent 1968;19:483-8.
125/135Abutment & Its Selection In FPD
126. • Yoav Grossmann, Avishai Sadan : The prosthodontic concept of
crown-to-root ratio: A review of the literature ; J Prosthet Dent
2005;93:559-62.
• Jerome.M.S and Robert.D.S Free end pontics used on fixed partia;
denture J.Prosthet.Dent 1968;20;121-138
• Igal Savion, Chris L. Saucier, Stefan Reus. The Pier Abutment :
Review of literature & suggested mathematical model,
Quintessence Int 2006 ; 37 : 345-352.
• Jepsen A: Root Surface Measurement and a Method for X-ray
Determination of Root Surface Area. Acta Odont. scandinav. 21:
35-46, 1963.
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127. • Lundgren D, Laurell L., Occlusal force pattern during chewing and
biting in dentitions restored with fixed bridges of cross extension,
J Oral Rehabil. 1986 Jan; 13(1):57-71
• William E Wright : Success with the Cantilever Fixed partial
denture. J Prosthet Dent ; May 1986, vol 55, 537-39.
• Richard Jacobi, Herbert Schillinburg Jr. Effect of abutment
mobility, site, and angle of impact on retention of fixed partial
dentures. J Prosthet Dent ; aug 1985, vol 54, 178-83.
• Jon P. Standlee, Angelo A. Caputo : Load transfer by fixed partial
dentures with three abutments : Quintessence Int; 1988.vol 19,
no.6, 403-9.
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Editor's Notes
No. of iopas
Fixed dental Prosthesis
Location areas of infection,
Accurate diagnostic casts must be correctly oriented to the transverse hinge axis and the pIane of occlusion on an articulator to permit eccentric movements similar to those that take place in the mouth.
33.34
33.33
Retention prevents removal of the restoration along the path of insertion or long axis of the tooth preparation.
Resistance prevents dislodgement of the restoration by forces directed in an apical or oblique direction and prevents any movement of the restoration under occlusal forces.
33.36
Boxes, grooves and pins
R 3-23 97 pg
T’he longer the edentulous span and the greater the torques on the abutment teeth, the morr favorable the crolvn-to-root ratio must be. The use of multiple abutments can sometimes compensate fox, poor croM,n-to-root ratios or for lorg spans.
T’he longer the edentulous span and the greater the torques on the abutment teeth, the morr favorable the crolvn-to-root ratio must be. The use of multiple abutments can sometimes compensate fox, poor croM,n-to-root ratios or for lorg spans.
T’he longer the edentulous span and the greater the torques on the abutment teeth, the morr favorable the crolvn-to-root ratio must be. The use of multiple abutments can sometimes compensate fox, poor croM,n-to-root ratios or for lorg spans.
T’he longer the edentulous span and the greater the torques on the abutment teeth, the morr favorable the crolvn-to-root ratio must be. The use of multiple abutments can sometimes compensate fox, poor croM,n-to-root ratios or for lorg spans.
Torque = moment of force (is the tendencey of a force to rotate an object about an axis, fulcrum or pivot )
Force is push or pull.
Torque is twist to an object
Secondary retention (R) must extend a distance from the primary interabutment axis equal to the distance that the pontic lever arm (P) extends in the opposite direction.
Torque = moment of force (is the tendencey of a force to rotate an object about an axis, fulcrum or pivot )
Force is push or pull.
Torque is twist to an object
Gargulio
Chronic pain
chronic inflammation of gingiva
Unpredictable loss of alveolar bone.
Pic bilogic width
Chronic pain
chronic inflammation of gingiva
Unpredictable loss of alveolar bone.
Pic bilogic width
EOM This is the mandibular movement created by the pt own neuromuscular movement pattern. (Dynamic relation)
EOF satic relationship which clinician can control. Esentially, it’s the pathway of mandibular movement created by the contours of the teeth. This means we can place teeth in different locations and it will dictate how the patient closes and moves.
Video
Flexure – the action of bending or curving Tension – streched tight
EOM This is the mandibular movement created by the pt own neuromuscular movement pattern. (Dynamic relation)
EOF satic relationship which clinician can control. Esentially, it’s the pathway of mandibular movement created by the contours of the teeth. This means we can place teeth in different locations and it will dictate how the patient closes and moves.
Video