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.