preserved contour and a greater show of mucosa. Pa-tients with loss of lip mass and contour after trauma alsooften request augmentation.

There are numerous methods currently used for lip aug-mentation, including implantation of alloplastic materialsand grafting of autologous tissue. The materials most fre-quently placed today are autologous fat, autologous dermis,a cadaveric acellular dermis matrix manufactured and mar-keted as AlloDerm (Lifecore Biomedical, Chaska, MN), andexpanded polytetrafluoroethylene (PTFE) (Gore-Tex; W.L.Gore & Associates, Inc, Flagstaff, AZ). None of these tissuesor materials is ideal for lip augmentation.

The ideal lip augmentation material should be biocom-patible, safe, infection resistant, soft, and flexible so as tofreely move with the lip and capable of being custom-ized to each patient situation. The material should notextrude when tunnelled in a superficial plane, shouldnot resorb, should not cause changes in lip sensation,and should feel even and natural to the patient.

Not only is there a relative paucity of scientific literaturerelated to lip augmentation, there are minimal publisheddata comparing the various common augmentation modal-ities. None of the augmentation tissues or materials havebeen compared in a controlled manner over time.

References

Tobin HA, Karas ND: Lip augmentation using an Alloderm graft.J Oral Maxillofac Surg 56:6, 1998

Wilkinson TS: Lip enhancement. Plast Reconstr Surg 92:7, 1993

S214Clinical Results of Titanium ScreeningUsed as Tissue Barriers or GuidedTissue RegenerationJohn R. Gay, BASc, DDS, FRCD, Toronto, Ontario,Canada

The presentation will outline clinical results of tita-nium screens and mesh used for Guided Tissue Regen-eration in a number of interesting clinical situations. Theclinical uses will include orthognathic surgery, facialreconstruction, implantology, and pathology.

Innovative and original techniques of use will beshown regarding:

• Rigid fixation for facial osteotomies, using theprinciples of guided tissue regeneration or tissuebarriers that may offer a reliable, efficient, andstable method of fixation and bone contouring,especially noted in downgrafts and advancementsof the mid-face

• Bone contouring for genioplasties and the con-tour-deficient chin

• Bone augmentation over the immediately placedimplant with interesting techniques for the atro-phied posterior mandible and the sinus lift

• The marsupialization of keratocystsThe titanium barriers appear to offer a biocompatible

and advantageous alternative to existing forms of GTR aswell as a good solution for certain clinical problems. Theadvantages and disadvantages, as established over 8years of clinical study, will be illustrated.

References

Gay J, Chung H, Chu A: Oral Health. May 7-21, 1997

S215Pharmacologic and Technologic Updatesin Office-Based Anesthesia PracticeRobert Campbell, DDS, Richmond, VA

Several anesthetic agents including propofol andsevoflurane are relatively new arrivals to the office-basedpractice. The pharmacokinetics of propofol comparefavorably to methohexital. If the latter returns to themarketplace, it can be mixed with propofol to incorpo-rate the “best qualities” of both. The induction doses forboth are similar whether for deep sedation or generalanesthesia. If anything, higher doses of propofol areneeded to accomplish the same clinical endpoint. Pro-grammable pumps are available and an efficient methodof delivering either propofol or a mixture of propofol/methohexital.

Sevoflurane has several desirable characteristics in-cluding rapid, smooth induction absence of bradycardia,cardiac arrhythmias, or significant hypotension. Its lowblood gas coefficient comparable to nitrous oxide invitesrapid recovery. Clinical cases will demonstrate thesequalities.

The laryngeal mask airway has universally not onlybecome an emergency airway instrument but is alsoused routinely for office-based third molar surgery par-ticularly for the difficult airway. Inhalation agents arerequired to place the LMA but muscle relaxants are NOT.

There are a few modestly priced gas machines avail-able either refurbished or new with 2 or 3 vaporizers anda ventilator option. To be fully prepared, it would beadvisable to be able to mechanically ventilate in order tocounteract respiratory acidosis in the event of an albeitrare but possible malignant hyperthermia. This condi-tion is not that difficult to treat if recognized earlyenough through capnography.

Summary: There are new exciting developments inoffice-based anesthesia. Some of these developments ad-mittedly have been stimulated by the expanded scope oforal and maxillofacial surgery, by weak financial reim-bursement for orthognathic surgery, and by the atten-tion that has drawn physician anesthesiologists to theoffice. Full scope anesthesia services are here and avail-able and monitoring has made it safer than ever in thehistory of office-based surgery.

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