Effect of chronic stress on implant osseointegration into rat's mandible.

PURPOSE

To compare chronic physical stressed with normal tense animals regarding implant osseointegration in the rat mandible.

METHODS

Thirty six Wistar rats were anesthesiaded and blunt instruments were used to expose and empty their alveolar inferior nerve. One implant (2.2 x 4mm) was installed into the mandibular canal. Following 72 hours, all rats were equally divided in: Control Group analyzed in 18 days (CG18); Control Group analyzed in 33 days (CG33); Stressed Group with stress during 18 days (SG18) and Stressed Group with stress during 33 days (SG33) - The animals from Stressed Groups (CG 18 and CG33) were placed individually in plastic pipes (PVC) during 12 hours daily to physical restraint. Histomorphometric analysis included bone-implant-contact (BIC) and bone area (BA).

RESULTS

In relation to BIC--CG18 (49.8+20.3); SG18 (29.0+16.5)--and BA--CG18 (50.13+21.2); SG18 (23.8+7.8)--, there was a bone repair delayed in SG18 when compared with CG18 (p<0.05). After 33 days, BIC--CG33 (59.6+26.8); SG33 (49.52+17.3)--and BA--CG33 (41.90+17.4); SG33 (43.91+14.7)--showed no difference between groups (p>0.05).

CONCLUSION

Chronic physical stress interfere with the initial stage of osseointegration in the rat mandible, but not the final process.