Chin implant surgery is typically very safe. It can be performed under local anesthesia, IV sedation or general anesthesia. The serious risks that you inquire about are rare and depend mainly upon your underlying health and the type of anesthesia you're undergoing. Serious complications are rare...
There is no connection surgically between a sliding genioplasty and the position of your teeth. The part of the jawbone in which the sliding genioplasty is done does not affect the part of the jawbone where the teeth are.
Soft tissue chin reduction is done through a submental approach from the underside of the chin. A wedge of soft tissue is removed down to the bone and then tucked from underneath. While it does produce a fine line scar on the underside of the chin, the key is to not let the excision/scar become...