1. RESIDUAL RIDGE RESORPTION
GUIDED BY:
DR. MANESH LAHORI
PROFF & HEAD
DEPT. OF PROSTHODONTICS
KDDC, MATHURA
PRESENTED BY:
DR. KUSHAL SINGH
P g STUDENT
4. INTRODUCTION
Residual ridge is a term used to describe the shape
of the clinical alveolar ridge after healing of bone and soft
tissues after tooth extractions.
After tooth extraction, a cascade of inflammatory
reactions is immediately activated, and the extraction
socket is temporarily closed by the blood clot. Epithelial
tissue begins its proliferation and migration within the
first week and the disrupted tissue integrity is quickly
restored.
5. The most striking feature of the extraction
wound healing is that even after the healing of
wounds, the residual alveolar ridge bone undergoes
a life-long catabolic remodeling. The size of the
residual ridge is reduced most rapidly in the first 6
months, but the bone resorption activity continues
throughout life at a slower rate, resulting in removal
of a large amount of jaw structure.
This unique phenomena has been described
as Residual Ridge Resorption (RRR).
6. Residual ridge resorption after loss of
teeth is a multifactorial oral problem. According
to Atwood, the degree of mandibular loss of its
alveolar portion is 3-4 times higher than alveolar
resorption in the maxilla. The rate of RRR is
different among persons and even at different
sites in the same person.
7.
8. Residual bone is considered to be the base which
provides support for dentures and is an area where forces
created while biting and chewing foods are transmitted.
Loss of alveolar bone from the edentulous jaws is a
serious and common clinical problem, especially among
the elderly.
In particular, “flat lower ridge” is associated with
difficulties in providing successful dentures. Stability of
lower denture in such cases is usually the distinguishing
factor between success and failure.
9. DEFINITIONS
• Residual ridge resorption :- A term used for the
diminishing quantity & quality of residual ridge
after teeth are removed. (G.P.T -8)
• Residual ridge :- The portion of the residual bone
& its soft tissue covering that remains after the
removal of teeth. (G.P.T -8)
• Residual bone :- That component of maxillary &
mandibular bone that remains after the teeth are
lost. (G.P.T -8)
10. ETIOLOGY OF RIDGE RESORPTION
• RRR depends not on one single factor but on the concurrence of
two or more factors, which may be called cofactors.
• The possible cofactors are divided into four categories:
a) ANATOMIC
b) METABOLIC
c) PROSTHETIC
d) FUNCTIONAL
11. ANATOMIC FACTORS
• RRR varies with quantity and quality of bone
of residual ridges.
• RRR α ANATOMIC FACTORS
AMOUNT OF BONE
QUALITY OF BONE:-
12. AMOUNT OF BONE
• More the amount of bone, more will be the RRR.
• But the amount of bone is not a good
prognosticator of the rate of RRR.
• If a low depressed ridge has existed for many
years, future RRR will be at a low rate
13. QUALITY OF BONE
• Mclean & urist (5) state that a loss of 24-30%
of bone salt is necessary to produce a
appreciable change in x-ray of bone.
• The denser the bone ,faster the rate of
resorption because there is more bone to be
resorbed per unit of time.
14. METABOLIC FACTORS
• RRR varies directly with certain systemic or
localized bone resorbing factors & inversely
with bone formation.
• RRR α BONE RESORBING FACTORS
BONE FORMATION FACTORS
15. In equilibrium the two antagonistic actions (of
osteoblasts and osteoclasts) are in balance. In growth,
although resorption is constantly taking place in the
remodeling of bones as they grow, increased osteoblastic
activity more than makes up for the bone destruction.
Whereas in osteoporosis, osteoblasts are
hypoactive, and, in the resorption related to
hyperparathyroidism, increased osteoblastic activity is
unable to keep up with the increased osteoclastic activity.
The normal equilibrium may be upset and pathologic
bone loss may occur if either bone resorption is
increased or bone formation is decreased, or if both
occur.
16. Since bone metabolism is dependent on cell
metabolism, anything that influences cell metabolism of
osteoblasts and osteoclasts is important.
The thyroid hormone affects the rate of
metabolism of cells in general and hence the activity of
both, the osteoblasts and osteoclasts.
Parathyroid hormone influences the excretion of
phosphorous in the kidney and also directly influences
osteoclasts.
17. • The degree of absorption of Ca, P and proteins
determines the amount of building blocks available
for the growth and maintenance of bone.
• Vit C aids in bone matrix formation.
• Vit D acts through its influence on the rate of
absorption of calcium in the intestines and on the
citric acid content of bone.
• Various members of Vit B complex are necessary for
bone cell metabolism.
18. Prosthodontic factors:-
Clinical observations indicate that excessive alveolar bone
resorption can be caused by physiologically intolerable forces
produced by functioning complete dentures.
The inherent denture factors which may affect the supporting structures
include:
The occlusal forms of the teeth.
a. The alignment of the denture teeth / occlusal pattern.
b. Deformation of the denture bases.
c. Materials with which denture teeth are made and
d. The effects of the loss of proper occlusal vertical dimension (over
closure).
19. The occlusal forms-
• The form of the occlusal surfaces of artificial teeth,
wether of the Anatomic, Non anatomic or 0 degree
configuration, must have some effect on chewing
efficiency and on forces tending to distort the denture
bases.
• One of the earliest opponents of the anatomic tooth
form was French who coined the term “cusp trauma”
as one of the most serious defects that had to be
guarded against in complete denture construction.
Soon after, Sear’s developed his non anatomic tooth
form which initiated the introduction of many new
designs to denture teeth throughout the years.
