Ridge = Soft tissue + bone

• Residual ridge resorption is a life long process. Residual ridge resorption is maximum upto 3 to 6 months and after that it tappers off.

Alveolar bone :- defined as a bony portion of maxilla and mandible held by the fibres of PDL.

Bone ( Dynamic Process)

Depending on the type of bone the resorption pattern varies like for spongy bone replaced 3-4 yrs and compact bone replaced 10yrs

Which is the process coupled that is bone deposition by osteoblast and bone resorption by osteoclast.

• Residual ridge resorption pattern varies in different individual

According to American college of prosthodontics

Based on bone ht

Type 1 :- residual bone height 21 mm

Type 2 :- residual bone height 16mm

Type 3:- residual bone height 11 – 13mm

Type 4 :- residual bone height 10mm

Type 1 is having good prognosis and type 4 is having poor prognosis that means it’s difficult to gain stability , retention and support

Epidemiology of residual ridge resorption

•It occurs world wide . RRR is accelerated in 1st 6 months with more loss in mandible than maxilla.

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• After menopause that is due to harmonal disturbances osteoblastic activity is very less and it’s dominated by osteoclastic activity

” RESORPTION OF MANDIBLE >>>> RESORPTION OF MAXILLA

Direction of bone resorption :-

• Maxilla resorbs upwards and inwards ( centripetal) to become progressively small

• Mandible resorbs outwards and progressively wider

Etiology of residual ridge resorption :-

• Anatomical factors that is quality and quantity of bone of residual ridge RRR is directly proportional to anatomical factors

• Metabolic process :- RRR is directly proportional to bone resorption factors and inversely proportional to formation factors

• Mechanical factors :- If there is excess stimulus or no stimulus resorption takes place

Consequences of residual ridge resorption :-

– loss of sulcus width and depth

– Displacement of muscle attachment to the ridge

– loss of vertical dimension of occlusion. Reduction of lower facial height

– Increase in relative prognathism. Changes in inter alveolar relation. Change in the location of mental foramen.

Treatment :-

– Prevention of loss of natural tooth. Change in the design of denture like impression technique by using minimal pressure impression and selective pressure impression techniques.

• Provide adequate relief on relief are areas. Avoidance of inclined planes. Centralization of occlusal contacts to increase stability and maximise compressive forces

• Adequate interocclusal distance that is by providing enough free way space . Occlusal table should be narrow .

Source :- Deepak nallaswamy and rangarajan.