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 presentation include general definition of bone and it's functions. Also, describe the chemical composition of bone and then specifically describe alveolar process.
In my presentation, I have described about the anatomy and physiology of bone and also did a elaboration on the pathways which is responsible for bone cells formation. For more details related to bone you can contact me on my email : sheershopramanik24@gmail.com
Bone physiologynew /certified fixed orthodontic courses by Indian dental acad...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 presentation include general definition of bone and it's functions. Also, describe the chemical composition of bone and then specifically describe alveolar process.
In my presentation, I have described about the anatomy and physiology of bone and also did a elaboration on the pathways which is responsible for bone cells formation. For more details related to bone you can contact me on my email : sheershopramanik24@gmail.com
Bone physiologynew /certified fixed orthodontic courses by Indian dental acad...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
10.13.08: Histology - Bone Formation and Remodeling Open.Michigan
Slideshow is from the University of Michigan Medical School's M1 Musculoskeletal Sequence
View additional course materials from Open.Michigan:
openmi.ch/med-M1Muscu
CONTENTS
FORMATION OF BONE
CLASSIFICATION OF BONES
STRUCTURE OF BONE
BLOOD SUPPLY
COMPOSITION OF BONE
FRACTURE HEALING
CARTILAGE
TYPES OF CARTILAGE
BONE (syn – Os; Osteon)
Osseous tissue, a specialised form of dense connective
tissue consisting of bone cells (osteocytes)
Embedded in a matrix of calcified intercelluar
substance
Bone matrix contains collagen fibres and the minerals
calcium phosphate and calcium carbonate
all the stages of bone formation described in easiest way possible for better understanding including graphical representation for better understanding. description of each and very thing.
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.
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
10.13.08: Histology - Bone Formation and Remodeling Open.Michigan
Slideshow is from the University of Michigan Medical School's M1 Musculoskeletal Sequence
View additional course materials from Open.Michigan:
openmi.ch/med-M1Muscu
CONTENTS
FORMATION OF BONE
CLASSIFICATION OF BONES
STRUCTURE OF BONE
BLOOD SUPPLY
COMPOSITION OF BONE
FRACTURE HEALING
CARTILAGE
TYPES OF CARTILAGE
BONE (syn – Os; Osteon)
Osseous tissue, a specialised form of dense connective
tissue consisting of bone cells (osteocytes)
Embedded in a matrix of calcified intercelluar
substance
Bone matrix contains collagen fibres and the minerals
calcium phosphate and calcium carbonate
all the stages of bone formation described in easiest way possible for better understanding including graphical representation for better understanding. description of each and very thing.
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.
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
Alveolar bone / /certified fixed orthodontic courses by Indian dental academy Indian dental academy
Welcome to 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 has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
A presentation on Articular Cartilage Repair for my Functional Anatomy Course. The presentation was short as we were limited to 6 slides.
I hope you find the information of some use.
10.08.08: Histology - Cartilage/Mature Bone Open.Michigan
Slideshow is from the University of Michigan Medical School's M1 Musculoskeletal Sequence
View additional course materials from Open.Michigan:
openmi.ch/med-M1Muscu
articular cartilage present in joint surface of articulating bone .role of articular cartilage in load bearing is important its damage cause arthritis so should know about its biomechanics
a brief ppt description about cartilage which may be usefull for teaching for first year mbbs, bds and paramedical students, hope it is helpfull to everyone
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
Bones and its structure in detail with two different form of bone formationbhartisharma175
It consist of detail content about different types of bone cells, two different type of bone formation and structure of long bone. easy to understand for students. language is simple.
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
Bone development and morphology / dental crown & bridge coursesIndian 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
The musculoskeletal system is made up of bones, cartilage, ligaments, tendons and muscles, which form a framework for the body. Tendons, ligaments and fibrous tissue bind the structures together to create stability, with ligaments connecting bone to bone, and tendons connecting muscle to bone.
The musculoskeletal system Anatomy and physiologykajal chandel
The musculoskeletal system is made up of bones, cartilage, ligaments, tendons and muscles, which form a framework for the body. Tendons, ligaments and fibrous tissue bind the structures together to create stability, with ligaments connecting bone to bone, and tendons connecting muscle to bone.
Opportunity for Dentists (BDS/MDS )to relocate to United kingdom -Register as a DENTAL HYGIENIST/ DENTAL THERAPIST without Board exams and after approval you can register in GDC as a DH/DT and start working as a DH/DT Immediately and get paid.
You can complete the whole process in 3-4 months.Salary range for DH/DT is around 2500-3500 Pounds per month.
Eligibility / requirements-
1. An International English Language Testing System (IELTS) certificate
at the appropriate level.(Within 2 yrs of application date )
2: A recent primary dental qualification that has been taught and examined in English..(Within 2 yrs of application date )
3: A recent pass in a language test for registration with a regulatory authority in a country where the first language is English.
If you are interested Please contact us for more details.
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...Indian dental academy
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.
I –Aligners are made with FDA approved transparent thermoplastic materials using 3D scanning, 3D Printing and finally Trays with Pressure vacuum formers.
Dear Doctor,
Indian Dental Academy Now offers comprehensive online Orthodontics course.
Course includes:
1.whiteboard lecture presentations
2.Case Discussions
3.with hundreds of pictures.
4.Demo on Models
5.Demo on Patients
6. subtitles in your own language
12 months unlimited access and support @350 USD only.
For Demo please visit :www.idalectures.com/preview/
For more details visit: www.idalectures.com
Please contact us for any clarifications:
idalectures@gmail.com
indiandentalacademy@gmail.com
Thanks & Regards
Indian Dental Academy
--
Indian Dental Academy
Leader in continuing dental education
www.indiandentalacademy.com
skype:indiandentalacademy
+919248678078
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
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...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.for more details please visit
www.indiandentalacademy.com
Diagnosis and treatment planning in completely endntulous arches/dental coursesIndian 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.for more details please visit
www.indiandentalacademy.com
Properties of Denture base materials /rotary endodontic coursesIndian 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.for more details please visit
www.indiandentalacademy.com
Use of modified tooth forms in complete denture occlusion / dental implant...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.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
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
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
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
2. CONTENTS
Introduction
Classification of bone
Functions of bone
Division of skeletal system
Structural anatomy of bones
Composition of bone
Osteogenesis
Physiology of bone
Disorders of bone
Bone healing
Correlation of bone structure & some of itsCorrelation of bone structure & some of its
propertiesproperties
www.indiandentalacademy.com
3. IntroductionIntroduction
BonesBones are rigidare rigid organsorgans that form part of thethat form part of the
endoskeletonendoskeleton ofof vertebratesvertebrates
One of the types of tissues that makes up bone is theOne of the types of tissues that makes up bone is the
mineralizedmineralized osseous tissueosseous tissue, also called bone tissue,, also called bone tissue,
that gives it rigidity and honeycomb-like three-that gives it rigidity and honeycomb-like three-
dimensional internal structure.dimensional internal structure.
www.indiandentalacademy.com
4. Other types of tissueOther types of tissue
found in bones includefound in bones include
marrowmarrow
endosteumendosteum andand
periosteumperiosteum,, nervesnerves,,
blood vesselsblood vessels andand
cartilagecartilage
www.indiandentalacademy.com
5. AA tendontendon (or(or sinewsinew) is a tough band of) is a tough band of
fibrous connective tissuefibrous connective tissue that connectsthat connects musclemuscle
toto bonebone and is capable of withstandingand is capable of withstanding tensiontension..
Tendons are similar toTendons are similar to ligamentsligaments except thatexcept that
ligaments join one bone to another.ligaments join one bone to another.
Tendons and muscles work together and canTendons and muscles work together and can
only exert a pulling forceonly exert a pulling force
www.indiandentalacademy.com
6. CartilageCartilage is a type of denseis a type of dense connective tissueconnective tissue..
It is composed of specialized cells calledIt is composed of specialized cells called chondrocyteschondrocytes
that produce a large amount of extracellular matrixthat produce a large amount of extracellular matrix
composed ofcomposed of collagencollagen fibers, abundantfibers, abundant
ground substanceground substance rich inrich in proteoglycanproteoglycan, and, and elastinelastin
fibers.fibers.
Cartilage is classified in three typesCartilage is classified in three types
elastic cartilageelastic cartilage
hyaline cartilagehyaline cartilage andand
www.indiandentalacademy.com
7. DIVISIONS OF THE SKELETAL SYSTEM
REGIONS OF THE
SKELETON
NUMBER OF BONES
AXIAL SKELETON
SKULL
Cranium 8
Face 14
Hyoid 1
Auditery ossicles 6
VERTIBRAL COLUMN 26
THORAX
sternum
ribs
1
24
80www.indiandentalacademy.com
9. CRANIAL BONES
a. Frontal Bone 1
b. Parietal Bone 2
c. TemporalBone 2
d. Occipital Bone 1
e. Sphenoid Bone 1
f. Ethmoid Bone 1
abb
c
d
e
f
www.indiandentalacademy.com
11. CLASSIFICATION OF BONES
A. According to Position
Axial : Bones forming the axis of the body,
e.g., skull, ribs, sternum and vertebrae.
Appendicular : Bones forming the skeleton
of limbs (appendages of the body).
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12. According to Size and Shape
1. Long Bones : present
in upper and lower limbs.
Possess three parts : (i)
upper end (ii) shaft (iii)
lower end.
The two ends are usually
expanded for forming
articulations and giving
attachments to muscles and
ligaments. The shaft is
tubular with a central
medullary cavity.
Examples : Humerus,
radius, ulna, femur, tibiawww.indiandentalacademy.com
13. 2. Short long bones :
Same as above but are
miniature in size.
Examples : Metacarpals,
metatarsals and
phalanges.
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14. 3. Short Bones :
Small, polyhedral and
generally cuboidal in
shape. Examples :
Carpal and tarsal bones.
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15. 4. Flat Bones : Expanded and plate like.
They protect vital structure and provide
extensive areas for muscular attachment.
Examples : Scapula, sternum, ribs, parietal and
frontal bones.
www.indiandentalacademy.com
16. 5. Irregular bones : Irregular in general outline and
do not fit in any of the above categories. Examples :
Vertebrae, some skull bones.
6. Pneumatic bones : Flat or irregular bones
possessing a hollow space within their body which
contains air. Presence of air filled spaces provide
economical methods of expansion of bones in size
and make them lighter. Examples : Ethmoid, maxilla
www.indiandentalacademy.com
17. 7. Sesamoid bones : Sesamoid means “seed
like”. They are nodules of bone which develop
in certain tendons and do not possess
periosteum and Haversian systems. They ossify
after birth. Examples : Pisiform, patella (which
is the largest sesamoid bone and develops in
quadriceps femoris tendon).
www.indiandentalacademy.com
18. C. According to Gross Structure
1. Compact (Lamellar)
Bone : the outer
cortical part of long
bones, which is hard
and has a
homogeneous
appearance.
www.indiandentalacademy.com
19. This tissue gives bones their smooth, white, and solidThis tissue gives bones their smooth, white, and solid
appearanceappearance
It is thickest midway between the two ends of the boneIt is thickest midway between the two ends of the bone
& gradually tapers towards the ends& gradually tapers towards the ends
Accounts for 80% of the total bone mass of an adultAccounts for 80% of the total bone mass of an adult
skeleton.skeleton.
Compact bone may also be referred to as dense boneCompact bone may also be referred to as dense bone
or cortical boneor cortical bone
Compact bone tissue provides protection and support
and helps the long bones resist the stress of weight
placed on them.
www.indiandentalacademy.com
21. Provides numerous
routes so that nutrients
can reach the osteocytes
and wastes can be
removed.
Each central canal,
with its surrounding
lamellae, lacunae,
osteocytes and
canaliculi, is called an
osteon (Haversian
system). The areas
between osteons contain
interstitial lamellae.
www.indiandentalacademy.com
22. Trabecular boneTrabecular bone
Filling the interior of theFilling the interior of the
organ is theorgan is the
trabecular bonetrabecular bone tissue (antissue (an
open cellopen cell porousporous networknetwork
also called cancellous oralso called cancellous or
spongy bone)spongy bone)
Accounts for the remainingAccounts for the remaining
20% of total bone mass,20% of total bone mass,
but has nearly ten times thebut has nearly ten times the
surface area of compactsurface area of compact
bone.bone.
Examples :Flat, Short and
Irregular Bones and ends
of long bones www.indiandentalacademy.com
23. It consists of an irregular
latticework of thin plates of
bone called Trabeculae.
The spaces between the
trabeculae of some bones
are filled with red marrow.
The cells of red marrow are
responsible for producing
blood cells. Within the
trabeculae lie lacunae, which
contain osteocytes.
www.indiandentalacademy.com
25. 3.Diploic Bone : Consists of inner and outer
tables of compact bone with an intervening
porous layer which is occupied by a spongy
substance consisting of bone marrow and
diploic veins e.g., most of cranial bones
www.indiandentalacademy.com
26. D. According to Development
Embroyonic mesenchymatous tissue is the
precursor of a bone, further development
occurs by two methods.
1. Membranous (Ectochondral) bones : Which
develop in membrane.
2. Cartilaginous (Endochondral) bones : Which
develop in cartilage.
www.indiandentalacademy.com
27. FunctionsFunctions
Bones have eight main functions:Bones have eight main functions:
Protection — Bones can serve to protect internalProtection — Bones can serve to protect internal
organs, such as theorgans, such as the skullskull protecting theprotecting the brainbrain or theor the
ribsribs protecting theprotecting the heartheart andand lungslungs..
Shape — Bones provide a frame to keep the bodyShape — Bones provide a frame to keep the body
supported.supported.
Blood production — TheBlood production — The marrowmarrow, located within the, located within the
medullary cavitymedullary cavity of long bones and interstices ofof long bones and interstices of
cancellous bone, produces blood cells in a processcancellous bone, produces blood cells in a process
calledcalled haematopoiesishaematopoiesis..www.indiandentalacademy.com
28. Mineral storage — Bones act as reserves of mineralsMineral storage — Bones act as reserves of minerals
important for the body, most notablyimportant for the body, most notably calciumcalcium andand
phosphorusphosphorus..
Movement — Bones,Movement — Bones, skeletal musclesskeletal muscles,, tendonstendons,,
ligamentsligaments andand jointsjoints function together to generate andfunction together to generate and
transfer forces so that individual body parts or thetransfer forces so that individual body parts or the
whole body can be manipulated in three-dimensionalwhole body can be manipulated in three-dimensional
space. The interaction between bone and muscle isspace. The interaction between bone and muscle is
studied instudied in biomechanicsbiomechanics..
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29. Acid-base balance — Bone buffers the blood againstAcid-base balance — Bone buffers the blood against
excessive pH changes by absorbing or releasingexcessive pH changes by absorbing or releasing
alkaline salts.alkaline salts.
Detoxification — Bone tissues can also storeDetoxification — Bone tissues can also store
heavy metalsheavy metals and other foreign elements, removingand other foreign elements, removing
them from the blood and reducing their effects onthem from the blood and reducing their effects on
other tissues. These can later be gradually released forother tissues. These can later be gradually released for
excretion.excretion.
Sound transduction — Bones are important in theSound transduction — Bones are important in the
mechanical aspect ofmechanical aspect of hearinghearingwww.indiandentalacademy.com
32. 4. Articular
cartilage : A thin
layer of hyaline
cartilagecovering
the epiphysis where
the bone forms a
joint with
another bone.
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33. 5. Periosteum : (peri= around;osteo= bone) A dense, white,
fibrous covering around the surface of the bone not covered
by articular cartilage. Two layers.
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34. Outer fibrous layer is
composed of
connective tissue
containing blood
vessels, lymphatic
vessels, and nerves that
pass into the bone.
Inner osteogenic
layer contains elastic
fibers, blood vessels,
osteoprogenitor cells,
osteoclasts, and
osteoblasts.
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35. Functions of periosteumFunctions of periosteum
Provides a medium through which muscles,Provides a medium through which muscles,
tendons & ligaments are attached to bonetendons & ligaments are attached to bone
Presence of blood vessels – nutritionPresence of blood vessels – nutrition
Presence of osteoprogenitor cells in deeperPresence of osteoprogenitor cells in deeper
layers – forms bone when requiredlayers – forms bone when required
Fibrous layer is sometimes calledFibrous layer is sometimes called limiting layerlimiting layer
prevents bone tissue from spilling out intoprevents bone tissue from spilling out into
neighboring tissues – exostoses, ridges, tubercleneighboring tissues – exostoses, ridges, tubercle
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36. 6. Medullary or marrow
cavity.
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37. 7. Endosteum. A layer
of osteoprogenitor cells
and osteoblasts that lines
and medullary cavity and
also contains scattered
osteoclasts
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38. COMPOSITION OF BONE
Organic part – 33% - 35%
Collagen – 88% - 90% (Type – I)
Non collagen – 10% - 11%.
Glycoproteins – 6% - 9%
Proteoglycans – 0.8% (sulfated and Non sulfated)
Sialoproteins – 0.35%
Lipids – 0.4%
Inorganic Part – 65% - 67%
- Calcium & Phosphates – 95%
(Hydroxyapatite Crystals – Ca10
(Po4
)6
(OH)2
)
- Magnesium
- Trace elements – Nickel, Iron, Fluoride, Cadmium,
Magnesium, Zinc and Molybdenum.
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39. Cellular structureCellular structure
OsteoblastsOsteoblasts areare
mononucleate bone-formingmononucleate bone-forming
cells which descend fromcells which descend from
osteoprogenitorosteoprogenitor cells locatedcells located
in thein the periosteumperiosteum and theand the
bone marrowbone marrow
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40. When bone is no longer forming, the surface
osteoblasts become inactive and are termed
lining cells
Osteoblasts exhibit high levels of alkaline
phosphate on the outer surface of their plasma
membranes, this distinguishes the osteoblast
from the fibroblast
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41. Osteoblasts secrete, in
addition to type I and
type V collagen and small
amounts of several
noncollagenous proteins,
a variety of cytokines.
Osteoblasts under the
stimulation of interleukin
6 also produce their own
hydrolytic enzymes that
aid in destroying or
modifying the
unmineralized matrix.
Thus freeing the
osteoblast from its own
secreted matrix.
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42. Osteoid is primarily composed of Type IOsteoid is primarily composed of Type I collagencollagen &&
matrix glaprotein (MGP) or osteocalcin.matrix glaprotein (MGP) or osteocalcin.
Other proteins are transforming growth factor (TGF),Other proteins are transforming growth factor (TGF),
insulin like growth factor (IGF) , fibroblast growthinsulin like growth factor (IGF) , fibroblast growth
factor (FGF) & platelet derived growth factorfactor (FGF) & platelet derived growth factor
(PDGF)(PDGF)
They produceThey produce alkaline phosphatasealkaline phosphatase, an enzyme that, an enzyme that
has a role in the mineralisation of bone, as well ashas a role in the mineralisation of bone, as well as
manymany matrix proteinsmatrix proteins
They cover all of the available bone surface andThey cover all of the available bone surface and
function as a barrier for certain ionsfunction as a barrier for certain ions
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43. OsteocytesOsteocytes originateoriginate
from osteoblasts whichfrom osteoblasts which
have migrated into andhave migrated into and
become trapped andbecome trapped and
surrounded by bonesurrounded by bone
matrix which theymatrix which they
themselves producethemselves produce
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44. Function –
Maintain bone as living
tissue because of their
metabolic activity
Maintain exchange of
calcium between bone &
ECF
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45. OsteoclastsOsteoclasts are the cellsare the cells
responsible forresponsible for
bone resorptionbone resorption
(remodeling of bone to(remodeling of bone to
reduce its volume).reduce its volume).
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46. Osteoclasts are large,Osteoclasts are large,
multinucleated cellsmultinucleated cells
located on bone surfaceslocated on bone surfaces
in what are calledin what are called
howships lacunae orhowships lacunae or
resorption pitsresorption pits
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47. These lacunae, or resorption pits, are left behindThese lacunae, or resorption pits, are left behind
after the breakdown of bone and often presentafter the breakdown of bone and often present
asas scallopedscalloped surfaces.surfaces.
Osteoclasts mature and/or migrate to discreteOsteoclasts mature and/or migrate to discrete
bone surfaces. Upon arrival, active enzymes,bone surfaces. Upon arrival, active enzymes,
such assuch as tartrate resistant acid phosphatasetartrate resistant acid phosphatase, are, are
secreted against the mineral substrate.secreted against the mineral substrate.
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49. Area of mesenchyme prior to mesenchymal condensation.
Intramembranous bone formationIntramembranous bone formation
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50. At the site where
membrane bone is
to be formed, the
mesenchymal cells
become densely
packed.
Region becomes
highly vascular
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54. Mineralisation involves osteoblasts secretingMineralisation involves osteoblasts secreting
vesiclesvesicles containing alkaline phosphatase.containing alkaline phosphatase.
This cleaves the phosphate groups and acts asThis cleaves the phosphate groups and acts as
the foci for calcium and phosphate deposition.the foci for calcium and phosphate deposition.
The vesicles then rupture and act as a centre forThe vesicles then rupture and act as a centre for
crystals to grow on.crystals to grow on.
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57. Endochondral bone formationEndochondral bone formation
Endochondral bone formation occurs at the
ends of all long bones, vertebrae, ribs and at the
head of the mandible and base of the skull.
Early in embryonic development, there is a
condensation of mesenchymal cells.
Cartilage cells differentiate from these
mesenchymal cells, chondroblast.
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59. The early stages of hypertrophy the chondroblasts
secrete mainly type II collagen
The combination of increased cell size and increased
cell secretion leads to an increase in the size of the
cartilaginous end of the bone.
As the chondroblast reaches maximum size, it
secretes type X collagen, chondrocalcin, and bone
sialoprotein, which create a matrix environment with
the potential to mineralize matrix.
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61. Within the perichondrium in the diaphysis, there is
increased vascularization, perichondrium coverts to a
periosteum and bone begins to form
The middle of the cartilage occurs, cells called
chondroclasts resorb most of the mineralized cartilage
matrix, making room for further vascular in growth.
Mesenchymal (perivascular) cells accompany the
invading blood vessels, proliferating and migrating
onto the remains of the mineralized cartilage matrix
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62. The mesenchymal cells differentiate into obsteoblasts and
begin to deposit osteoid on the mineralized cartilage columns
and then to mineralize it.
As the bone matrix is produced, the mineralized cartilage
matrix becomes an irregularly shaped central zone core for a
circular rim of new bone matrix.
Some of the osteoblasts are surrounded by bone matrix and
become osteocytes. Collectively termed the primary
spongiosa
Osteoclasts progressively remove both the core of mineralized
cartilage and the surrounding bone. This process occurs at
approximately the same rate as cartilage formation, so volume
of the primary spongiosa remains relatively constant.www.indiandentalacademy.com
64. Bone physiologyBone physiology
Calcium Stores – Amount and Distribution
• Bone: major reservoir of calcium: 99% of calcium is in
skeleton; about 1-2 kg
• Less than 1% (about 10g) is in soft tissues and
body fluids
Normal Plasma calcium level – 9.4 mg %Normal Plasma calcium level – 9.4 mg %
Normal PTH level is 10-60 ng/L
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65. Vitamin D PTH Calcitonin
Blood calcium Increased Drastically
increased
Decreased
Main action Absorption from
gut
Demineralisation Opposes
demineralization
Calcium
absorption from
gut
Increased Increased
(Indirect)
Bone resorption Decreased Increased Decreased
Deficiency
manifestation
Rickets Tetany
Effect of excess Hypercalcemia+ Hypercalcemia+ + Hypocalcemia
Comparison of action of three major factors affecting serum
calcium
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66. Growth Hormone
• Stimulates overall growth, particularly epiphyseal
cartilage
• Produced in anterior lobe of pituitary gland
• Lack causes pituitary dwarfism
• Excess causes gigantism
• Epiphyseal plates are already closed in adults: bones can
not elongate; excess GH causes increases in width by
periosteal growth; cause acromegaly, in which bones
become very thickened
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67. Thyroid Hormone
Lack of thyroxine causes arresting of growth
There is early closure of epiphysis
• Childhood deficiency is associated with
dwarfism and cretinism
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68. Bone Nutrition
• Insufficient protein: decrease in collagen
synthesis by osteoblasts
Rickets
• Inadequate vitamin D in children
•Can lead to permanent deformities of skeleton
• Vitamin D required for calcium absorption
(vitamin D stimulates mineralization of bone)
• Collagen and mucopolysaccharides continue to
form but don’t calcifywww.indiandentalacademy.com
69. • Leads to uncalcified osteoid at growing ends
of bone
• Easily deformed by strains of body weight
and activity
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70. Osteomalacia
• Calcium or vitamin D deficiency in adults (adult
rickets)
• Osteomalacia: osteon + Gr. malakia, softness
• Deficient calcification of recently formed bone and
partial decalcification of already calcified matrix
• Decrease in amount of calcium per unit of bone Matrix
Decrease in bone mass: due to decreased bone formation,
increased bone resorption, or both
• Increased fracture risk, especially of vertebrae, hip,
wrist/forearm
• Common in elderly
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71. Scurvy
• Associated with vitamin C deficiency
• Vitamin C necessary for osteoblasts to form normal
amount of collagen
• Causes local changes in calcification sites
• Formation of osteoid tissue is reduced and bone cortex
thickness is decreased as a result
• Collagen formed is normal but deficient; still becomes
mineralized
• Collagen deficiency stunts skeletal growth in the young
• Collagen deficiency retards fracture healing
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72. OsteoporosisOsteoporosis
Osteoporosis is aOsteoporosis is a diseasedisease of bone - leading to anof bone - leading to an
increased risk ofincreased risk of fracturefracture..
In osteoporosis, theIn osteoporosis, the bone mineral densitybone mineral density
(BMD) is reduced, bone microarchitecture is(BMD) is reduced, bone microarchitecture is
disrupted, and the amount and variety of non-disrupted, and the amount and variety of non-
collagenouscollagenous proteins in bone is altered.proteins in bone is altered.
Osteoporosis is most common in women afterOsteoporosis is most common in women after
thethe menopausemenopause, when it is called, when it is called
postmenopausal osteoporosispostmenopausal osteoporosis
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73. But may develop in men and premenopausalBut may develop in men and premenopausal
women in the presence of particular hormonalwomen in the presence of particular hormonal
disorders and otherdisorders and other chronicchronic diseases or as adiseases or as a
result ofresult of smokingsmoking andand medicationsmedications, specifically, specifically
glucocorticoidsglucocorticoids
steroid-steroid- oror glucocorticoid-inducedglucocorticoid-induced
osteoporosisosteoporosis (SIOP or GIOP).(SIOP or GIOP).
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74. Normal is a T-score of -1.0 or higherNormal is a T-score of -1.0 or higher
OsteopeniaOsteopenia is defined as less than -1.0 and greater thanis defined as less than -1.0 and greater than
-2.5-2.5
OsteoporosisOsteoporosis is defined as -2.5 or lower,is defined as -2.5 or lower, Z-scoreZ-score
The Z-score is the number of standard deviations aThe Z-score is the number of standard deviations a
patient's BMD differ from the average BMD of theirpatient's BMD differ from the average BMD of their
age, sex, and ethnicity.age, sex, and ethnicity.
This value is used in premenopausal women, menThis value is used in premenopausal women, men
under the age of 50, and in children.under the age of 50, and in children.
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75. Risk Factors
1. Female > 50
2. Postmenopausal
3. First degree female relative with osteoporosis
4. Thin build, small bone (genetic, anorexic, excessive athleticism
with estrogen suppression)
5.Caucasian or Asian
6. Prolonged use of cortisone or prednisone
,hyperparathyroidism, antiseizure therapy (e.g. Dilantin)
7. Decreased estrogen levels
8. Early or surgically-induced menopause
< age 45 www.indiandentalacademy.com
77. Pagets diseasePagets disease
Paget’s disease is also called osteitis deformans.Paget’s disease is also called osteitis deformans.
It is named after Sir James Paget, an EnglishIt is named after Sir James Paget, an English
doctor who first described the disease in 1876.doctor who first described the disease in 1876.
Paget’s disease causes a malfunction in thePaget’s disease causes a malfunction in the
normal process of bone remodelling.normal process of bone remodelling.
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78. When an area of bone is destroyed in a personWhen an area of bone is destroyed in a person
with Paget’s disease, the bone that replaces it iswith Paget’s disease, the bone that replaces it is
soft and porous.soft and porous.
Soft bone can be weak and easily bend, leadingSoft bone can be weak and easily bend, leading
to shortening of the affected part of the body. to shortening of the affected part of the body.
The bone replacement also takes place veryThe bone replacement also takes place very
quickly and excess bone may be formed. Thisquickly and excess bone may be formed. This
can cause the bone to get larger, be painful andcan cause the bone to get larger, be painful and
break easily.break easily.
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79. The bone affected by Paget’s disease also tends toThe bone affected by Paget’s disease also tends to
have more blood vessels than normal. This causes anhave more blood vessels than normal. This causes an
increase in the blood supply to the area, and as aincrease in the blood supply to the area, and as a
result the area may feel warmer than usual.result the area may feel warmer than usual.
The disease can affect any bone but more commonlyThe disease can affect any bone but more commonly
affects the spine, pelvis, skull, femur and tibiaaffects the spine, pelvis, skull, femur and tibia
Paget’s disease can lead to other medical conditionsPaget’s disease can lead to other medical conditions
including osteoarthritis, kidney stones and heartincluding osteoarthritis, kidney stones and heart
disease.disease.
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80. If Paget’s disease affects skull, head mayIf Paget’s disease affects skull, head may
increase in size from front to back. Hearing lossincrease in size from front to back. Hearing loss
may result if there is involvement of some of themay result if there is involvement of some of the
small bones in the middle ear or pressure issmall bones in the middle ear or pressure is
placed on the nerves related to hearing.placed on the nerves related to hearing.
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82. Immobilization and surgery may facilitate healingImmobilization and surgery may facilitate healing
Fracture ultimately heals through physiologicalFracture ultimately heals through physiological
processes.processes.
The healing process is mainly determined by theThe healing process is mainly determined by the
periosteumperiosteum
The periosteum is the primary source of precursorThe periosteum is the primary source of precursor
cells which develop intocells which develop into chondroblastschondroblasts andand
osteoblastsosteoblasts that are essential to the healing of bone.that are essential to the healing of bone.
The bone marrow , endosteum, small blood vessels,The bone marrow , endosteum, small blood vessels,
and fibroblasts are secondary sources of precursorand fibroblasts are secondary sources of precursor
cellscells
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83. Phases of fracture healingPhases of fracture healing
1.1. Reactive PhaseReactive Phase
i. Fracture and inflammatory phasei. Fracture and inflammatory phase
ii. Granulation tissue formationii. Granulation tissue formation
2.2. Reparative PhaseReparative Phase
iii. Callus formationiii. Callus formation
iv. Lamellar bone depositioniv. Lamellar bone deposition
3.3. Remodeling PhaseRemodeling Phase
v. Remodeling to original bone contourv. Remodeling to original bone contour
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84. ReactiveReactive
The first change seen by light and electron microscopy is theThe first change seen by light and electron microscopy is the
presence of blood cells within the tissues which are adjacent topresence of blood cells within the tissues which are adjacent to
the injury site.the injury site.
Soon after fracture, the blood vessels constrict, stopping anySoon after fracture, the blood vessels constrict, stopping any
further bleeding.further bleeding.
[1]Within a few hours after fracture, the extravascular blood[1]Within a few hours after fracture, the extravascular blood
cells, known as a "hematoma", form a blood clot. All of thecells, known as a "hematoma", form a blood clot. All of the
cells within the blood clot degenerate and diecells within the blood clot degenerate and die
[2]Some of the cells outside of the blood clot, but adjacent to the[2]Some of the cells outside of the blood clot, but adjacent to the
injury site, also degenerate and die.injury site, also degenerate and die.
[3]Within this same area, the fibroblasts survive and replicate.[3]Within this same area, the fibroblasts survive and replicate.
They form a loose aggregate of cells, interspersed with smallThey form a loose aggregate of cells, interspersed with small
blood vessels, known as granulation tissueblood vessels, known as granulation tissue
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85. ReparativeReparative
The cells of the periosteum replicate and transform.The cells of the periosteum replicate and transform.
The periosteal cells proximal to the fracture gap develop intoThe periosteal cells proximal to the fracture gap develop into
chondroblasts and form hyaline cartilage.chondroblasts and form hyaline cartilage.
The periosteal cells distal to the fracture gap develop intoThe periosteal cells distal to the fracture gap develop into
osteoblasts and form woven bone.osteoblasts and form woven bone.
The fibroblasts within the granulation tissue also develop intoThe fibroblasts within the granulation tissue also develop into
chondroblasts and form hyaline cartilage.chondroblasts and form hyaline cartilage.
These two new tissues grow in size until they unite with theirThese two new tissues grow in size until they unite with their
counterparts from other pieces of the fracture.counterparts from other pieces of the fracture.
This process forms theThis process forms the fracture callusfracture callus..
Eventually, the fracture gap is bridged by the hyaline cartilageEventually, the fracture gap is bridged by the hyaline cartilage
and woven bone, restoring some of its original strengthand woven bone, restoring some of its original strengthwww.indiandentalacademy.com
87. RemodelingRemodeling
The remodeling process substitutes the trabecularThe remodeling process substitutes the trabecular
bone with compact bonebone with compact bone
The trabecular bone is first resorbed by osteoclasts,The trabecular bone is first resorbed by osteoclasts,
creating a shallow resorption pit known as acreating a shallow resorption pit known as a
"Howship's lacuna"."Howship's lacuna".
Then osteoblasts deposit compact bone within theThen osteoblasts deposit compact bone within the
resorption pit.resorption pit.
Eventually, the fracture callus is remodelled into aEventually, the fracture callus is remodelled into a
new shape which closely duplicates the bone's originalnew shape which closely duplicates the bone's original
shape and strength.shape and strength.www.indiandentalacademy.com
88. Phase IPhase I
1. Bleeding and fracture hematoma forms1. Bleeding and fracture hematoma forms
2. Inflammation2. Inflammation
3. Next 2-3 Days, granulation tissue formation3. Next 2-3 Days, granulation tissue formation
4. Osteogenic Cells invade tissue and lay down osteoid4. Osteogenic Cells invade tissue and lay down osteoid
Phase IIPhase II
5. At 3 weeks a soft callus forms consisting of osteoid5. At 3 weeks a soft callus forms consisting of osteoid
and cartilageand cartilage
6. Hard tissue callus forms in 6 - 12 weeks6. Hard tissue callus forms in 6 - 12 weeks
7. Clinical union of bone ends occurs in 12 - 16 weeks7. Clinical union of bone ends occurs in 12 - 16 weeks
Phase IIIPhase III
8. Remodeling of united fracture8. Remodeling of united fracture
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89. Correlation of bone structure & someCorrelation of bone structure & some
of its propertiesof its properties
Effect of function on bone was noted first inEffect of function on bone was noted first in
femurfemur
Meyer an anatomist with the help ofMeyer an anatomist with the help of
mathematician Cullmann in 1867 propoundedmathematician Cullmann in 1867 propounded
what was later to be calledwhat was later to be called the trajectorialthe trajectorial
theory of bone formationtheory of bone formation
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90. The alignment of bonyThe alignment of bony
trabeculae in spongiosatrabeculae in spongiosa
followed a definitefollowed a definite
engineering principlesengineering principles
If lines were drawnIf lines were drawn
following columns offollowing columns of
oriented bony elements-oriented bony elements-
trajectories similar totrajectories similar to
those seen in cranethose seen in crane
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91. Many of these trajectories crossed at right angles- anMany of these trajectories crossed at right angles- an
excellent arrangement to resist the manifold stressesexcellent arrangement to resist the manifold stresses
on the condyle of the femuron the condyle of the femur
The design of the femur in its entirety was in harmonyThe design of the femur in its entirety was in harmony
with the best engineering principleswith the best engineering principles
Femur is hollowed tube , using the same amount ofFemur is hollowed tube , using the same amount of
material it was best able to resist bending & shearingmaterial it was best able to resist bending & shearing
stressesstresses
If the cross section of femur was solid with sameIf the cross section of femur was solid with same
cross sectional material the shaft would be smaller &cross sectional material the shaft would be smaller &
weakerweaker
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93. (John G. Skedros and Sidney L. Baucom)(John G. Skedros and Sidney L. Baucom) TheThe
trabecular tracts from the tension- and compression-trabecular tracts from the tension- and compression-
loaded sides of a bending environment will:loaded sides of a bending environment will:
(1) follow ‘lines’ (trajectories) of tension/compression(1) follow ‘lines’ (trajectories) of tension/compression
stress that resemble an arch with its apex on a neutralstress that resemble an arch with its apex on a neutral
axisaxis
(2) form orthogonal (90°) intersections. These predictions(2) form orthogonal (90°) intersections. These predictions
were analysed in proximal femora of chimpanzees andwere analysed in proximal femora of chimpanzees and
modern humans.modern humans.
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94. Wolff's lawWolff's law by the Germanby the German
Anatomist/Surgeon Julius Wolff (1836-1902Anatomist/Surgeon Julius Wolff (1836-1902))
States that bone in a healthy person or animalStates that bone in a healthy person or animal
will adapt to the loads it is placed under.will adapt to the loads it is placed under.
He claimed that trabecular alignment wasHe claimed that trabecular alignment was
primarily due to functional forcesprimarily due to functional forces
Roux & others introduced functional factors inRoux & others introduced functional factors in
the development of “ law of transformation ofthe development of “ law of transformation of
bone”bone”
It stated that the stresses of tension or pressureIt stated that the stresses of tension or pressure
on bone stimulate bone formationon bone stimulate bone formation
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95. If loading on a particular bone increases, the bone willIf loading on a particular bone increases, the bone will
remodel itself over time to become stronger to resistremodel itself over time to become stronger to resist
that sort of loading.that sort of loading.
The external cortical portion of the bone becomesThe external cortical portion of the bone becomes
thicker as a result.thicker as a result.
The converse is true as well: As it is lessThe converse is true as well: As it is less
metabolically costly to maintain and there is nometabolically costly to maintain and there is no
stimulus for continued remodeling that is required tostimulus for continued remodeling that is required to
maintain bonemaintain bone
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96. ExamplesExamples
The racquet-holding arm bones of tennis playersThe racquet-holding arm bones of tennis players
become much stronger than those of the other arm.become much stronger than those of the other arm.
Their bodies have strengthened the bones in theirTheir bodies have strengthened the bones in their
racquet-holding arm since it is routinely placed underracquet-holding arm since it is routinely placed under
higher than normal stresses.higher than normal stresses.
Astronauts who spend a long time in space will oftenAstronauts who spend a long time in space will often
return to Earth with weaker bones, since gravity hasn'treturn to Earth with weaker bones, since gravity hasn't
been exerting a load on their bones. Their bodies havebeen exerting a load on their bones. Their bodies have
reabsorbed much of the mineral that was previously inreabsorbed much of the mineral that was previously in
their bonestheir bones
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97. Weightlifters often display increases in boneWeightlifters often display increases in bone
density in response to their training.density in response to their training.
Fighters who punch or kick objects withFighters who punch or kick objects with
increasing intensity (or of increasing hardness)increasing intensity (or of increasing hardness)
to develop striking power to damage opponents,to develop striking power to damage opponents,
often display increases in bone density in theoften display increases in bone density in the
striking area.striking area.
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98. Abnormal pressure on bone can change – patients withAbnormal pressure on bone can change – patients with
scoliosis who are treated with milwaukee bracescoliosis who are treated with milwaukee brace
Constant pressure produces marked effect on verticalConstant pressure produces marked effect on vertical
dimension & teethdimension & teeth
Stimulating influence of muscles causes bone toStimulating influence of muscles causes bone to
change-change-
Adaptive changes occur in Muscles & soft tissue butAdaptive changes occur in Muscles & soft tissue but
once growth is complete muscles cannot lengthen toonce growth is complete muscles cannot lengthen to
accommodate an increase in bony bulkaccommodate an increase in bony bulk
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99. In pathologic situationIn pathologic situation
like acromegaly there islike acromegaly there is
morphologic change inmorphologic change in
the bone as it adapts tothe bone as it adapts to
length of mature muscleslength of mature muscles
which are not aswhich are not as
responsive to sameresponsive to same
endocrine stimulusendocrine stimulus
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100. In alveolar process surrounding teeth that have noIn alveolar process surrounding teeth that have no
opposing dental units the radiographs show looseopposing dental units the radiographs show loose
trabecular structure – generalised radiolucencytrabecular structure – generalised radiolucency
surrounding non functional teethsurrounding non functional teeth
Restoration of these teeth by artificial replacementRestoration of these teeth by artificial replacement
brings an increase in bony trabeculaebrings an increase in bony trabeculae
(Benninghoff ) study of architecture of cranial & facial(Benninghoff ) study of architecture of cranial & facial
skeleton & stress trajectories – involve both cortical &skeleton & stress trajectories – involve both cortical &
spongy bonespongy bone
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101. Purposefulness of design accounts for shape ofPurposefulness of design accounts for shape of
human headhuman head
Maximum strength with minimum materialMaximum strength with minimum material
Sinus cavities in headSinus cavities in head
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102. According to Benninghoff stress trajectoriesAccording to Benninghoff stress trajectories
obeyed no individual bone limits but demandsobeyed no individual bone limits but demands
of functional forcesof functional forces
So head is composed of only 2 bones –So head is composed of only 2 bones –
craniofacial skeletal unit & mandible( the onlycraniofacial skeletal unit & mandible( the only
movable bone)movable bone)
Stress trajectories emanating from above theStress trajectories emanating from above the
teeth in maxillary arch passing superiorly toteeth in maxillary arch passing superiorly to
zygomatic arch or jugal buttresszygomatic arch or jugal buttress
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103. There are 3 main vertical pillars of trajectories, allThere are 3 main vertical pillars of trajectories, all
arising from alveolar process & ending in base of skullarising from alveolar process & ending in base of skull
The canine pillarThe canine pillar
The zygomatic pillarThe zygomatic pillar
The pterygoid pillarThe pterygoid pillar
These trajectories curve around the sinuses & nasal &These trajectories curve around the sinuses & nasal &
orbital cavitiesorbital cavities
Horizontal reinforcing members for vertical stressHorizontal reinforcing members for vertical stress
trajectory columns- supraorbital & infraorbital bonytrajectory columns- supraorbital & infraorbital bony
eminences & zygomatic buttresseseminences & zygomatic buttresses
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104. The canine pillarThe canine pillar
The zygomatic pillarThe zygomatic pillar
The pterygoid pillarThe pterygoid pillar
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105. Also included are hard palate, walls of orbit,Also included are hard palate, walls of orbit,
Lesser wings of sphenoid.Lesser wings of sphenoid.
Sicher emphasizes the importance ofSicher emphasizes the importance of
supraorbital rim as a receptor of forcessupraorbital rim as a receptor of forces
transmitted to it by canine & zygomatic pillarstransmitted to it by canine & zygomatic pillars
He believes that development of supraorbitalHe believes that development of supraorbital
ridge in lower primates & man is an adaptiveridge in lower primates & man is an adaptive
response to strong prognathism & heavyresponse to strong prognathism & heavy
masticatory pressuresmasticatory pressures
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106. Mandible- a unit byMandible- a unit by
itself & a movableitself & a movable
bonebone
Trabecular columnsTrabecular columns
radiate from beneathradiate from beneath
the teeth in thethe teeth in the
alveolar process joinalveolar process join
together in a commontogether in a common
stress pillarstress pillar
terminating interminating in
mandibular condylemandibular condyle
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107. Mandibular canal & nerveMandibular canal & nerve
are protected at the sameare protected at the same
time by this concentrationtime by this concentration
of trabeculae – “ unloadedof trabeculae – “ unloaded
nerve concept”nerve concept”
Thick cortical layer ofThick cortical layer of
compact bone along thecompact bone along the
lower border of mandiblelower border of mandible
offers the greatestoffers the greatest
resistance to bendingresistance to bending
forcesforces
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108. Other trajectories – sumphysis , gonial angle &Other trajectories – sumphysis , gonial angle &
leading downward from coronoid process intoleading downward from coronoid process into
the ramus & body of mandiblethe ramus & body of mandible
Accessory trajectories are due to direct effect ofAccessory trajectories are due to direct effect of
attachments of muscles of masticationattachments of muscles of mastication
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109. BibliographyBibliography
Graber T.M :Orthodontics Principles And Practice, ThirdGraber T.M :Orthodontics Principles And Practice, Third
ed., Philadelphia 1996, W.B. Saunders Company,129-134ed., Philadelphia 1996, W.B. Saunders Company,129-134
Enlow DH, Hans MG: Essentials of Facial Growth,
W.B. Saunders, ed. 3, 1996, Philadelphia
John G. Skedrosand Sidney L. Baucom,MathematicalJohn G. Skedrosand Sidney L. Baucom,Mathematical
analysis of trabecular ‘trajectories’ in apparentanalysis of trabecular ‘trajectories’ in apparent
trajectorial structures: The unfortunate historicaltrajectorial structures: The unfortunate historical
emphasis on the human proximal femur , julyemphasis on the human proximal femur , july
2006,Elsevier,Edition 1.2006,Elsevier,Edition 1.
Alexandrridis caputo Thanos,Alexandrridis caputo Thanos, J Oral Rehabil. 1985J Oral Rehabil. 1985
Nov;12(6):499-507Nov;12(6):499-507www.indiandentalacademy.com
110. W.Eugene Robertsa , James K Hartsfield ,Bone
development and function: genetic and environmental
mechanisms
Brighton, Carl T. and Robert M. Hunt (1986),Brighton, Carl T. and Robert M. Hunt (1986),
"Histochemical localization of calcium in the fracture"Histochemical localization of calcium in the fracture
callus with potassium pyroantimonate: possible role ofcallus with potassium pyroantimonate: possible role of
chondrocyte mitochondrial calcium in calluschondrocyte mitochondrial calcium in callus
calcification",calcification", Journal of Bone and Joint SurgeryJournal of Bone and Joint Surgery,, 68-A (5)68-A (5)::
703703
Ten Cate AR: Oral Histology, ed.3, 1989, C.V Mosby,Ten Cate AR: Oral Histology, ed.3, 1989, C.V Mosby,
30-35.30-35.
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111. Text book of Medical Physiology – Guyton and
Hall – 9th Edition
Principles of Anatomy and Physiology – Gerard J.
Tortora – 6th & 8th Editions
Gray’s Anatomy – Peter L. Williams – 38th
Edition
Oral Histology – Richard Tencate – 5th Edition
Orban’s Oral Histology and Embryology – S.N.
Bhaskar – 10th Edition
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