BY-MOHIT MALVIYAINTERN PDA

MANAGEMENT OF RESIDUAL RIDGE REDUCTION (RRR) IN

COMPLETE DENTURE

CONTENT

INTRODUCTIONCONSEQUENCES OF RRRPATHOLOGY ETIOLOGYPREVENTIONMANAGEMENTREFERENCE

INTRODUCTION

Residual ridge is term used to describe the shape of clinical alveolar ridge after healing of bone and soft tissue following extraction.

Post tooth extraction, a cascade if inflammatory reactions is activated , and the extraction socket is sealed temporarily by blood clotting.

Epithelial tissue begins its proliferation and migration within first week and disrupted tissue integrity is quickly restored.

Histological evidence of active bone formation is seen as early as 2 week after extraction and socket is progressively filled with newly formed bone in about 6 months.

But, even after the wound healing ,the residual ridge alveolar bone undergoes a lifelong catabolic remodeling.

The size of residual ridge is reduced most rapidly in the first six month, but the bone resorption activity continues throughout life at a slower rate.

The RRR is different among persons and even at different times and sites in the same person.

CONSEQUENCES OF RRR

1. There is apparent loss of sulcus width and depth.2. Muscles attachment are displaced closer to the

crest of residual ridge.3. Due to loss of vertical dimension lower facial height

is reduced and mandible is rotated anteriorly.4. Inter-alveolar width is altered.5. Morphologic changes in RR may appear such as

sharp , spiny, uneven residual ridge.6. Resorption of mandibularcanal wall and exposure of

nerve.7. Location of the mental foramen close to the top of

the mandibular residual ridge.

PATHOLOGY of RRR

The basic change in RRR is a reduction in size of bony ridge under mucoperiosteum.

There exists a wide variety of shapes and sizes of residual ridges. They are categorized into common residual ridge configuration in a system of six orders given by Atwood.

• 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

Microscopic Pathology: Revealed osteoclastic activity on the external

surface of the crest of residual ridges.varying degrees of inflammatory cells are

found in areas that appear from clinically normal to frankly inflamed in edentulous pts or who wear denture or non – denture wearers.

ETIOLOGY OF RRR

It is a multifactorial , biomechanical disease that result from combination of Anatomic , Metabolic and Mechanical determinants.

ANATOMIC FACTORS :I. Amount of boneII. Quality of boneA. Amount of bone-Broader ridge have a greater

potential for bone loss.B. Quality of bone : the denser the bone , the slower

the rate of bone resorption because there is more bone to be resorbed per unit area.

METABOLIC FACTORS :

1. Bone resorption factors2. Bone formation factorsa) The THYROID harmone affect the rate of metabolism of cell in

general and hence the activity of both, the osteoblast and osteoclasts.

b) PARATHYROID HARMONE influence the excretion of phosphorous in the kidney and also directly influence osteoclast.

c) Vit C aids in bone matrix formation.d) Vit D acts through its influence on the rate of absorption of

calcium in the intestines and on the citric acid content of bone.e) Various member of Vit B complex are necessary for bone cell

metabolism.

OSTEOPOROSIS AND RESIDUAL RIDGE MODELING :

TYPE 1 osteoporosis is defined as the specific consequence of menopausal estrogen deprivation, presents the bone mass loss, notably in trabecular bone.

TYPE 2 Osteoporosis reflects a composite of age related changes in intestinal, renal and hormonal function . Both cortical and trabecular bone are affected in type 2 osteoporosis.

FUNCTIONAL FACTORS: Includes1. Frequency2. Intensity3. Duration4. Direction of forces on applied to bone

which are translated into cellular activity, resulting in either bone formation or bone Resorption, depending upon the patient’s individual resistance to these forces.

PROSTHETIC FACTORS : Includes1. Broad – area coverage ( to reduce the force per

unit area)2. Decrease number of dental units.3. Decrease buccolingual width of teeth.4. Improved tooth form (to decrease the amount of

forces required to penetrate a bolus of food).5. Avoidance of inclined plane (to minimize

dislodgement of denture and shear forces).6. Centralization of occlusal contacts (to increase

stablity of denture and to maximize compressive forces).

7. Provision of adequate tongue room (to increase stability of denture in speech and mastication).

8. Adequate interocclusal distance during rest jaw relation (to decrease the frequency and duration of tooth contact).

PREVENTION AND MANAGEMENT OF RRR

Prevention is the best management : Means1. Overdentures – minimize ridge Resorption ,

enhance retention stability , support of prosthesis along with preservation of proprioception.

2. Implant supported Overdentures.3. Impression technique-the main aim of the

impression procedure is to gain maximum area of coverage , e.g., in mandibular ridge , obtaining a fairly long retromylohyoid flange helps to achieve a better border seal and retention.

4. Correcting the occlusal vertical dimension: o Increased VDO is common cause of RRR.o 2-5 mm of freeway space is guideline, but may

need to be increased in older pts or for those pts with atrophic mucosa with residual ridge.

5. Reducing the forces required to drive the denture teeth through the bolus of food: achieved by

o Increasing the denture bearing area , (done by using greenstick compound)

o Reducing the size and altering the morphology of the occlusal table.

6. Eliminating disruptive occlusal contacts which lead to denture in stablity.

SUMMARRY AND CONCLUSION

RRR is a multi-factorial , biomechanical disease that results from a combination of anatomic , metabolic and mechanical determinants.

But all these factors vary from one pt to next.RRR is chronic , progressive , irreversible

and cumulative.So it is important to incorporate measures so

as to minimize resorption of residual ridge in our treatment plan.

REFERENCE

ARTICLE ON RRR BY Dr.AJAY GUPTAESSENTIAL OF COMPYETE DENTURE

PROSTHODONTICS, WINKLER

THANK YOU