Hi In case of convectional implant it is the  delayed loading process and the alveolar crestal home is used for this which is more prone to resorption...It is not suitable for patients with Diabetes,smoking,and periodontal disease In case of basal implants,it is the one with immediate loading and it can be used be almost suitable for everyone...Here the basal bone is used which is very dense...... In case of you are smoker do not go with implants ...Implants will fail in case of poor dental maintanence... Yes you can go with basal implant at the same site of conventional implants as the basal implants are fixed in basal bone and the one conventional implant on the crestal alveolar bone.... Apart from implant you can also go for fixed bridges which is suitable for patients with Diabetes,smoker,etc