The document discusses residual ridge resorption (RRR), which is the progressive loss of jaw bone after tooth extraction. It defines RRR and provides classifications. RRR is considered a pathological process due to its variability between individuals. The document covers the epidemiology, etiology, and risk factors of RRR, including anatomical, mechanical, metabolic and prosthetic factors. Treatment aims to prevent or reduce RRR through denture design and patient education.
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
This presentation specifically deals with the maxillary and mandibular Major connectors used in a cast partial denture. it also mentions the uses, advantages and disadvantages of each,
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
This presentation specifically deals with the maxillary and mandibular Major connectors used in a cast partial denture. it also mentions the uses, advantages and disadvantages of each,
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
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
Residual ridge resorption /certified fixed orthodontic courses by Indian dent...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
Rrr final1 /certified fixed orthodontic courses by Indian dental academy 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
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
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
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
skeletal disorders of metabolic and endocrine originyashovrattiwari1
Metabolic bone diseases encompass a spectrum of disorders characterized by abnormalities in bone metabolism, structure, and mineralization. These conditions often result from disturbances in the intricate balance between bone formation and resorption, leading to weakened bones prone to fractures, deformities, and other complications. This comprehensive exploration will delve into the pathophysiology, clinical manifestations, diagnostic approaches, and management strategies for various metabolic bone diseases, shedding light on these complex yet fascinating conditions.
Introduction to Metabolic Bone Diseases
The skeleton serves as the structural framework of the body, providing support, protection, and mobility. Maintaining the integrity and strength of bones relies on a delicate equilibrium between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Disruptions in this equilibrium can give rise to metabolic bone diseases, which can be classified broadly into two categories: disorders of bone remodeling and mineralization.
Disorders of Bone Remodeling
Osteoporosis
Osteoporosis stands as the most prevalent metabolic bone disease, characterized by decreased bone mass and microarchitectural deterioration, predisposing individuals to increased fracture risk, particularly in the hip, spine, and wrist. Postmenopausal women and elderly individuals are at heightened risk due to hormonal changes and age-related bone loss. Contributing factors include inadequate calcium and vitamin D intake, sedentary lifestyle, smoking, and excessive alcohol consumption. Dual-energy X-ray absorptiometry (DXA) is the gold standard for diagnosing osteoporosis, and management strategies focus on lifestyle modifications, calcium and vitamin D supplementation, and pharmacological interventions to mitigate fracture risk.
Osteogenesis Imperfecta (OI)
OI, often referred to as brittle bone disease, encompasses a group of genetic disorders characterized by fragile bones prone to fractures, skeletal deformities, and short stature. Mutations affecting the synthesis or structure of type I collagen, the primary protein component of bone, underlie this condition. OI exhibits considerable clinical heterogeneity, ranging from mild forms with few fractures to severe cases associated with significant morbidity and mortality. Management involves a multidisciplinary approach, encompassing supportive measures, physical therapy, and surgical interventions to optimize bone health and function.
Paget's Disease of Bone
Paget's disease represents a disorder of excessive bone remodeling, marked by focal areas of increased bone resorption and disorganized bone formation, resulting in enlarged and weakened bones. Though the exact etiology remains elusive, environmental and genetic factors likely contribute to its pathogenesis. Affected individuals may present with bone pain, deformities, and complications such as fractures, nerve compression, and secondary osteoarthritis.
Biology of bone in complete dentures, removable partial denture, overdenturePiyaliBhattacharya10
describes the biology of bone in physiologic condition, about bone remodeling, bone resorption in complete denture, combination syndrome, bone resorption in immediate denture and overdenture
Dental Implant lecture concerning with bone resorption would take care of practice in the dental implant and help in considering the bone density as well as dental implant successful procedures.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
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
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
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
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.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
HOT NEW PRODUCT! BIG SALES FAST SHIPPING NOW FROM CHINA!! EU KU DB BK substit...GL Anaacs
Contact us if you are interested:
Email / Skype : kefaya1771@gmail.com
Threema: PXHY5PDH
New BATCH Ku !!! MUCH IN DEMAND FAST SALE EVERY BATCH HAPPY GOOD EFFECT BIG BATCH !
Contact me on Threema or skype to start big business!!
Hot-sale products:
NEW HOT EUTYLONE WHITE CRYSTAL!!
5cl-adba precursor (semi finished )
5cl-adba raw materials
ADBB precursor (semi finished )
ADBB raw materials
APVP powder
5fadb/4f-adb
Jwh018 / Jwh210
Eutylone crystal
Protonitazene (hydrochloride) CAS: 119276-01-6
Flubrotizolam CAS: 57801-95-3
Metonitazene CAS: 14680-51-4
Payment terms: Western Union,MoneyGram,Bitcoin or USDT.
Deliver Time: Usually 7-15days
Shipping method: FedEx, TNT, DHL,UPS etc.Our deliveries are 100% safe, fast, reliable and discreet.
Samples will be sent for your evaluation!If you are interested in, please contact me, let's talk details.
We specializes in exporting high quality Research chemical, medical intermediate, Pharmaceutical chemicals and so on. Products are exported to USA, Canada, France, Korea, Japan,Russia, Southeast Asia and other countries.
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.
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
3. DEFINITIONS :
“Bone - a highly vascularised, living, constantly
changing, mineralized connective tissue”. [Gray’s
Anatomy-40th edition]
“Alveolar process -- that part of the maxilla and
mandible that forms and supports the sockets of the
teeth”. [Orban’s]
4. “Alveolar bone is the bony portion of the maxilla and
the mandible in which roots of the teeth are held by
fibers of periodontal ligament”. [GPT-8]
5. “Residual alveolar ridge is the portion of the
alveolar ridge and its soft tissue covering
which remains following the removal of or loss
of teeth.
[GPT-8]
6. The residual bony architecture of the maxilla and
mandible undergoes a life-long catabolic remodelling.
The rate of reduction in size of the residual ridge is
maximum in the first 3-6 months and then
gradually tapers off.
However, bone resorption activity continues
throughout life at a slower rate, resulting in loss of
varying amount of jaw structure, ultimately leaving
the patient a ‘dental cripple’.
8. According to Atwood’s :
(JPD 1971 Vol.26)
Order 1 : Pre-extraction
Order 2 : Post-
extraction
Order 3 : High, well
rounded
Order 4 : Knife-edge
Order 5 : Low, well
rounded
Order 6 : Depressed
Pre
extraction Post ext High well rounded
Knife edge Low well rounded Depressed
9.
10. Immediately following the extraction (Order II), any sharp
edges remaining are rounded off by external osteoclastic
resorption leaving a high well rounded ridge (Order III).
As resorption continues from the labial and lingual
aspects ,the crest of the ridge becomes increasingly narrow,
ultimately becoming knife edged (Order IV).
As the process continues, the knife-edge becomes shorter
and eventually disappears leaving a low well-rounded or flat
ridge (Order V). Eventually this too resorbs, leaving a
depressed ridge (Order VI).
11. Class I : Upto one third of the original vertical
height lost.
Class II : From one third to two thirds of the
vertical height lost.
Class III : Two third or more of the mandibular
height lost.
12. Based on Bone Height (Mandible only)
Type I : Residual bone height of 21 mm or greater
measured at the least vertical height of the mandible.
Type II : Residual bone height of 16 - 20 mm measured
at least vertical height of the mandible.
Type III : Residual alveolar bone height of 11 - 15 mm
measured at the least vertical height of the mandible.
Type IV : Residual vertical bone height of 10 mm or less
measured at the least vertical height of the mandible.
13. Some clinicians feel that RRR is not a disease but a
normal physiological process.
However there is wide variation in the rate of RRR
in different individuals- depending on multiple
factors.
The need to elucidate these major differences
warrants labeling this process a “ disease” or
“pathology”
14. “Until a process is recognized as a disease entity,
little progress is made in understanding its
etiology and in developing adequate treatment
and prevention.”
- Douglas Allen
Atwood
15. Based on the clinical fact that :
•RRR is not inevitable
• Its rate varies
• The rate of resorption is greater that the rate of
formation in some patients ,
….RRR should be considered a pathologic process.
16.
17.
18.
19. Epithelial tissues begin its proliferation and migration
within the first week and the disrupted tissue integrity
is quickly restored.
Histologic evidence of active bone formation is seen
as early as 2 weeks after the extraction and the
socket is progressively filled with newly formed bone
in about 6 months..
The most striking feature of the extraction wound
healing is that even after the healing of wounds, the
residual ridge undergoes a lifelong catabolic
remodeling.
20. • This unique phenomenon has been described as
RESIDUAL RIDGE RESORPTION (RRR).
• The rate of RRR is different among persons and
even at different sites in the same person.
21. Coupled process between:
1. Bone deposition by osteoblasts
2. Bone resorption by osteoclasts
5-7% of bone mass recycled weekly
All spongy bone replaced every 3-4 years.
All compact bone replaced every 10 years.
Prevents mineral salts from crystallizing; protecting
against brittle bones and fractures
23. Patient has an expression “ My gums have
shrunken”
RRR Is primarily a localized loss of bone structure.
In some cases it may leave excessive and redundant
overlying mucoperiosteum and in some cases it may
not.
24.
25. In dry specimens
*External cortical surface of maxilla and mandible are
uniformly smooth & crestal area of residual ridge
shows porosities and imperfections.
*Bones with more severe RRR display gross porosities
of medullary bone on the crest of ridge.
26. Panoramic radiograph showing severe RRR in both
maxilla and mandible in contrast to dentulous
area that support three mandibular teeth.
27. Osteoclastic activity occurs on
the external surface of crest of
ridges .
Scalloped margins of
Howships lacunae sometimes
contain visible osteoclasts.
Frequently the scalloped
external surface seems
inactive without bone
resorbing cells.
28. The sequence of resorptive events is
considered to be
Attachment of osteoclasts to mineralized surface of bone
Creation of a ruffled border and a sealed acidic
environment through action of the proton pump
Dissolution of the Hydroxyapatite
Fall in pH to 2.5-3 in the osteoclast resorption space
Digestion of the organic components of the matrix by
proteolytic enzymes
29. 1. Serial Examination of
diagnostic casts.
2. Lateral cephalometric
radiographs
◦ Most accurate
◦ Measures RRR over a period
of time.
30. {Kenneth E. Wical and Charles C. Swoope. Studies of
residual ridge resorption. Uses panaromic radiographs for
evaluation and classification of mandibular resorption.
JPD;1974;32;7}
31. EPIDEMIOLOGY OF RRR:
•To date, it appears that RRR world-wide, occurs in
males and females, young and old, sickness and in
health, with and without dentures and is unrelated to
the primary reason for the extraction of the teeth
(Caries / periodontal disease).
• Rate of RRR is variable
-between persons.
-within the same person at different times.
-within the same person at different sites.
32. According to Boucher,
During the first year after tooth extraction, the
reduction in residual ridge height in the
midsagittal plane is
2-3 mm for maxilla
4-5 mm for mandible
Annual rate of reduction in height
0.1-0.2 mm for mandible
4 times less in the maxilla
33. Maxilla resorbs upward and
inward to become progressively
smaller because of the direction
and inclination of the roots of the
teeth and the alveolar process.
The opposite is true of the
mandible, which inclines outward
and becomes progressively wider.
This progressive change of the
edentulous mandible and maxilla
makes many patients appear
prognathic.
34. •Thus, RRR is centripetal in maxilla and
centrifugal in mandible.
35. In the Mandible, large proportions of bone loss
occurs in the
labial side of anterior residual ridge,
equally on the buccal and lingual side in premolar
region and
lingually in the posterior or molar region.
In the Maxilla bone loss primarily occurs on the
labial or buccal aspect.
36. While teeth arrangement we should try to restore
the natural position of the teeth before they were
lost, Hence teeth in the maxillary arch are arranged
slightly labially and buccally .
While in the mandible, teeth in the anterior region
are arranged labially, on the centre of the ridge in
the premolar region and slightly lingually in the
molar region.
37. It is a clinically acknowledged fact that the anterior
mandible resorbs 4 times faster than the anterior
maxilla.
Woelfel et al have cited the projected maxillary denture
area to be 4.2 sq in and 2.3 sq in for the mandible;
which is in the ratio of 1.8:1.
If a patient bites with a pressure of 50 lbs, this is
calculated to be 12 lbs/sq in under the maxillary
denture and 21 lbs/sq under the mandibular
denture. The significant difference in the two forces
may be a causative factor to cause a difference in the
rates of resorption.
Maxilla V/s Mandible
38. Cancellous bone is ideally designed to absorb and
dissipate the forces it is subjected to.
The maxillary residual ridge is often broader,
flatter, and more cancellous than the mandibular
ridge.
Trabeculae in maxilla are oriented parallel to the
direction of compression deformation, allowing for
maximal resistance to deformation.
The stronger these trabeculae are, the greater is
the resistance.
39. ◦ Generally more in mandible than in maxilla but the
reverse may also occur….
◦ So one must treat every patient as a “PARTICULAR
PATIENT, NOT THE AVERAGE PATIENT!”!
•RRR is chronic, progressive, irreversible, and
cumulative.
•Autonomous regrowth has not been reported.
40. Acc. To Atwood… {Some clinical factors related to
rate of resorption of residual ridges JPD Vol 12,issue
3, pages 441-450.
RRR is a multifactorial biomechanical disease
caused by a combination of
◦ ANATOMIC FACTORS
◦ MECHANICAL FACTORS
◦ METABOLIC FACTORS
41. It is postulated that RRR varies with the quantity and
quality of the bone of residual ridges..
ie, the more bone there is, the more RRR will
ultimately be.
But this cannot be considered a good prognostic
factor, because in some cases large ridges resorb
rapidly and some knife-edge ridges may remain with
little change for long periods of time.
RRR α Anatomic factors
42. We should always try to evaluate the present status
of the residual ridge to determine what has gone on
before.
If a ridge has existed as high and well rounded
(order III) for several years, it will likely to continue
to do so.
But if a ridge has gone from an order II to order IV
in just two years it will probably continue to resorb
rapidly.
43. RRR varies directly with certain systemic or
localized bone resorptive factors and inversely with
certain bone formation factors.
RRR BONE RESORPTION FACTORS
BONE FORMATION FACTORS
44. BONE RESORPTION FACTORS
LOCAL SYSTEMIC
-Endotoxins from dental plaque
-Osteoclast activating factor(OAF)
-Prostaglandins
-Human gingival bone resorption
factor
-Trauma due to ill fitting dentures
which leads to increased or
decreased vascularity and changes
in oxygen tension.
-Correct amount of circulating
estrogen, thyroxine, growth
hormone, calcium,
phosphorus,
-vitamin D ,
-Osteoporosis
- Hypophosphetemia
- Parathormone
- Calcitonin
45. Osteoporosis is defined by the WHO as bone
mineral density (BMD) greater than 2.5
standard deviations below that of the young
adult BMD.
Osteoporosis is common in aging individuals,
especially post menopausal women when the
estrogenic blood level is low.
In elderly men and women, osteoporosis is caused
by a variety of factors such as calcium loss,
calcium deficiency, hormonal deficiency, change in
protein nutrition and decreased physical activity.
48. Residual ridge resorption of the jaws is also more
rapid in increasing age group, depleted bone being
prone to the injurious impact of mechanical forces.
49. The most popular theory of how osteoporosis occur
in females is based on the central role of oestrogen
in bone remodelling.
50. Decreased oestrogen levels leads to
increased pro-inflammatory cytokine
levels like IL1 and TNF leading to
increased osteoclast formation and
hence increased bone loss.
Oestrogen acts through two
receptors: oestrogen receptor a (ERa)
and ERb, ERa appears to be the
primary mediator of the actions of
oestrogen on the skeleton.
Another line of action is the decreased
antagonistic action of oestrogen on
parathyroid leads to more
parathormone secretion and
consequently increased bone
resorption.
51.
52. One
• loss and/or mobility of teeth
Two
• edentulism,
Three
• excessive residual ridge resorption
Four
• dentures which require repeated
revision or remakes
53. Mandibular and maxillary radiographs are suggested
in screening patients for osteoporosis for two reasons
potential frequency of dental radiographs
compared to the rest of the body
the prosthodontic implications of osteoporosis.
Bone density may be assessed by a prosthodontist
using linear measurements (morphometric
analysis) or by measuring optical density of bone
(densitometric analysis).
54. Bone that is used by regular physical activity will tend
to strengthen within certain limits, than the bone that
is in “disuse atrophy”, while others postulated that
due to denture wearing RRR is caused due to an
“abuse” bone resorption.
Perhaps there is truth in both the hypotheses.
The fact is that with or without dentures some patients
have little or no RRR and some have severe RRR.
55. When force is considered one must be concerned not
only about the amount of force but also with the
frequency of force, the duration, the area over which the
force is distributed and the damping effect of underlying
tissue.
The amount of force applied to the bone may be affected
inversely by the damping effect or energy absorption.
RRR α Force
1
RRR α ———————-
Damping effect
56. The damping effect is due to the viscoelastic
property of the mucoperiosteum and may vary
from patient to patient and also from maxilla to
mandible.
Cancellous bone helps in the absorption and
dissipation of forces and is more in maxilla than
mandible, which could be a reason in the
difference in RRR between them.
57. Excessive stress resulting from artificial environment.
Abuse of tissues from lack of rest-
Bone is moldable. It can tolerate masticatory forces
within the limits of physiologic tolerance.
• But exceeding that it causes damaging forces which will
result in resorption of the alveolar bone.
PROSTHETIC FACTORS
58. Long continued use of ill fitting dentures:
• may be due to : Long use, Loss of bone, Incorrect
occlusion, Incorrect jaw relation
Lack of freeway space due to increased vertical
dimension of occlusion:
• Freeway space is present in the teeth in the
physiologic rest position. It is normally around
2mm.
• At times, due to lack of freeway space the bone
resorbs because of increased vertical height in an
attempt to create the space.
59. Incorrect Centric relation record:
• If the Centric relation is not recorded properly, the
mandibular teeth will not occlude properly with those on
the maxillary arch. This proper occlusion is essential to
the health of bony support.
• Otherwise, during eccentric movement, it causes pressure
on bone due to failure of denture stability. Hence
resorption of base occurs.
60. If occlusal corrections are not done:
• These errors which may be caused due to processing
techniques if not corrected causes premature contacts
resulting in increased stress.
• Selective grinding should be done to minimize lateral
stress and resulting tissue trauma.
61. Kelly first described the “combination syndrome”
wherein patients with remaining mandibular natural
teeth against a maxillary complete denture were
shown to have an exaggerated loss of anterior
segment of maxillary residual ridge.
62. In addition to the 3 major categories of factors
(anatomic, metabolic and mechanical) the
importance of time since extraction is also
important. This can be added to the formula by an
inverse relation.
Bone resorption factors Force
factors
RRR α anatomic factors + ———————————— + ————
——— +
Bone formation factors Damping
effect
1
——
Time
63. Apparent loss of sulcus width
and depth.
Displacement of muscle
attachment close to the ridge.
Loss of vertical dimension of
occlusion.
Reduction of the lower face
height.
Increase in relative
prognathia
64. Changes in inter alveolar relationship.
Morphological changes of the alveolar bone such as
sharp, spiny uneven residual ridges.
Location of mental formina close to the ridge crest.
65. “Treatment of RRR is ideally by preventing it.”
a. Prevention of loss of natural teeth:
Alveolar bone supporting natural teeth receives
tensile loads through a large area of periodontal
ligament.
While the edentulous residual ridge receives
vertical, diagonal and horizontal loads applied by a
denture with a surface area much smaller than the
total area of the periodontal ligament of all the
natural teeth that had been present.
66. Optimal tissue health prior to making impression.
Impression procedures
Minimal pressure impression technique.
Selective pressure impression technique: places
stress on those areas that best resist functional
forces
Adequate relief of non stress bearing areas eg.
Crest of mandibular ridge.
Broad area of coverage helps in reducing the
force /unit area(Snow Shoe Effect)
67. Avoidance of inclined planes to minimize dislodgment of
dentures and shear forces.
Centralization of occlusal contacts to increase stability and
maximize compressive forces.
Provision of adequate tongue room to improve stability of
denture in speech and mastication.
Adequate interocclusal distance during jaw rest to decrease
the frequency and duration of tooth contact.
Occlusal table should be narrow
The concept and arrangement of teeth in neutral zone helps
the teeth to occupy a space determined by the functional
balance of the oro- facial and tongue musculature.
68. It has been seen that one of the cofactor in RRR is
low calcium and vitamin D metabolism.
Diet counseling for prosthodontic patients is
necessary to correct imbalances in nutrient
intake.
Denture patients with excessive RRR report lower
calcium intake and poorer calcium phosphorus
ratio, along with less vitamin D.
69. Excessive RRR leads to loss of sulcus width and
depth with displacement of muscle attachment more
to the crest of residual ridge.
Osseous reconstruction surgeries, removal of high
frenal attachments, augmentation procedures,
vestibuloplasties etc may be required to correct
these conditions.
71. e. Immediate dentures:
Some authors claim that extraction followed by
immediate dentures reduces the ridge resorption.
72. f. Overdentures
Tooth supported over dentures
help in improved stress
distribution there by maintaining
the integrity of residual ridge.
The occlusal and parafunctional
stresses are distributed through
the abutment teeth.
A study was conducted with overdentures supported
by canines and it was seen that, the bone loss was
0.6mm where as 5mm in conventional complete
dentures.
73. 1. The denture bearing mucosa of the residual ridges
are spared abuse.
2. Maintenance of the alveolar bone.
3. Sensory feedback.
4. Tactile sensitivity discrimination.
5. Masticatory performance.
6. Reduction of Psychological trauma.
74. The introduction of osseointegrated implants has
eclipsed traditional preprosthetic surgical techniques.
The use of implant-supported overdentures resembles
the same clinical situation of teeth supported
overdentures.
75. Metal based denture with soft liner is advocated
in patients with severely atrophic residual ridges.
Metal base provides-
◦ Weight necessary to facilitate retention
◦ Maintain Adequate strength with modest extensions
The soft liner accomodates ridge irregularities
and changes.
Metal based dentures {JPD 1987 ;57:6 }
76. Precautions during extraction to
reduce RRR
◦ When a tooth is removed the labial plate should be
preserved.
◦ The labial periosteal covering should remain intact as
its inner layer is responsible for remodeling of bone.
◦ If a bone has to be removed it must be the palatal plate.
77. The ultimate aim of a successful prosthesis is
stability in function and excellent esthetics.
The expectations of edentulous patients are highly
variable therefore the outcome of patient treatment
varies significantly.
Patients should be educated regarding the type and
extent of treatment that is ideal for them, the
prognosis of the treatment outcomes with various
types of removable or fixed prostheses and the
alternatives that are available.