This experimental research shows that a class III clasp partial dentures should present four Akers clasps. This way the occlusal rests are placed as closely as possible to the edentulous area on both sides of the arch and the abutment teeth are less stressed than if the occlusal rests are further away from saddles. On the other hand, a lingual bar of average rigidity i.e. of a thickness of 1.7-2.0 mm must be recommended. It gives sufficient resistance to the framework while allowing better distribution of force. Finally, oblique forces applied on a tooth borne unilateral prosthesis cause an increase of 65.5 per cent in abutment teeth displacement compared to forces applied to a more favorable bilateral tooth borne prosthesis.