A patient is presented in whom augmentation of the pyriform aperture of the maxilla was performed with porous hydroxyapatite in concert with a face and brow lift. Basic research has recently shown that remodeling of the facial skeleton continues throughout life and that this remodeling process leads to changes in the position of several key areas. The pyriform aperture was identified as one region that remodels in a posterior direction, leading to retrusion of the alar base in the older individual. This skeletal retrusion occurs in a very site-specific fashion, and its effects are reflected on the overlying soft tissues of the face. With aging, remodeling of the pyriform aperture posteriorly causes the alar base to appear recessed and decreases the nasolabial angle, changes that are noted on the profile of the older individual. Augmentation of the pyriform aperture can be achieved through a buccal sulcus incision and, when used in conjunction with standard facial rejuvenation procedures, can improve the overall result in facial cosmetic surgery.

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Semiempirical AM1 molecular orbital calculations are used to compute the energetics of addition of the guanine 2-amino group to alternative ring positions of aryl nitrenium ions with the general structure ArNH+, where Ar is the phenyl and various positional isomers of the naphthyl, pyrenyl, and benzo[a]pyrenyl groups. The syn or anti orientation of the NH+ group, and factors akin to classical localization energies, are identified as key components of the differential energetics of addition to alternative ring sites. The regiochemistry predicted by the AM1 method can be qualitatively reproduced using simple HMO calculations that require trivial computational effort and, almost as well, using PMO theory that does not require the use of a computer at all. In the latter approach, the most reactive ring positions are predicted to be those where the nonbonding orbital coefficients, a0r, in the analogous odd alternant hydrocarbons are largest. These results are discussed in relation to the available experimental data for the formation of deoxyguanosin-2-yl adducts when DNA is exposed to presumed nitrenium ion precursors.