SOFT-TISSUE CHANGES ASSOCIATED WITH DOUBLE JAW SURGERY

The purpose of this study was to evaluate the amount, direction, and predictability of the soft tissue changes associated with simultaneous maxillary impaction and mandibular advancement surgery. The results suggested that the soft tissue responses were similar to those seen in single jaw procedures, with the exception of the changes seen in the nasolabial angle and in the area of the lower lip and chin. The type of soft tissue manipulation employed, in particular the use of the alar base cinch suture and V-Y closure techniques, were important factors in determining the response of the upper lip to the surgery. The maxillary soft tissues moved forward 90% of the hard tissue change and showed 20% shortening of the upper lip, with the changes in the nasolabial angle being due primarily to the degree of the maxillary rotation. A predictable progressive increase was seen in the horizontal movement of the mandibular soft tissues ranging from 73% of the hard tissue change at the lower lip to 100% at pogonion. The vertical movement of the mandibular soft tissue was greater than that of underlying hard tissues, particularly in the area of the lower lip as it was freed from the effects of the maxillary incisors.