Residual ridge resorption 44

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RESIDUAL RIDGE RESORPTION GUIDED BY: DR. MANESH LAHORI PROFF & HEAD DEPT. OF PROSTHODONTICS KDDC, MATHURA PRESENTED BY: DR. KUSHAL SINGH P g STUDENT

Transcript of Residual ridge resorption 44

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RESIDUAL RIDGE RESORPTION

GUIDED BY:

DR. MANESH LAHORIPROFF & HEAD

DEPT. OF PROSTHODONTICS

KDDC, MATHURA

PRESENTED BY:

DR. KUSHAL SINGH

P g STUDENT

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CONTENTS

INTRODUCTION

DEFINITIONS

ETIOLOGY

PATHOLOGY

PATHOPHYSIOLOGY

PATHOGENESIS

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EPIDEMIOLOGY

TREATMENT & PREVENTION OF RRR

SUMMARY

BIBLIOGRAPHY

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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.

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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).

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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.

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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.

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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)

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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

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ANATOMIC FACTORS

• RRR varies with quantity and quality of bone of residual ridges.

• RRR α ANATOMIC FACTORS

AMOUNT OF BONE

QUALITY OF BONE:-

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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

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QUALITY OF BONE

• Mclean & urist (5) state that a loss of 24-30% of bone salt is necessary to produce aappreciable 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.

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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

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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 osteoblasticactivity 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.

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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.

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• 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.

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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 andd. The effects of the loss of proper occlusal vertical dimension (over

closure).

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The occlusal forms-

• The form of the occlusal surfaces of artificial teeth,wether of the Anatomic, Non anatomic or 0 degreeconfiguration, must have some effect on chewingefficiency and on forces tending to distort the denturebases.

• One of the earliest opponents of the anatomic toothform was French who coined the term “cusp trauma”as one of the most serious defects that had to beguarded against in complete denture construction.Soon after, Sear’s developed his non anatomic toothform which initiated the introduction of many newdesigns to denture teeth throughout the years.