Periodontal disease is an inflammatory condition that affects the supporting structures of the teeth which eventually lead to bone loss, tooth mobility and tooth loss if left untreated.Bone loss in periodontal disease is a hall mark and the patterns of bone loss is based on the type of periodontal destruction present.A number of factors contribute to bone loss in periodontitis like bacterial derived factors, antigens that stimulate a local inflammatory response and activation of innate immune system.The present review gives us an overview of classification of bone defects, bone loss patterns specific to each periodontal condition and factors influencing bone loss.