The vertical dimension may be very important clinically where anatomic structures may limit the bone height available for implant insertion. Moreover, lack of bone tissue may result in exposure of implant threads, soft tissue recession, less-than-optimal implant stability, and esthetic problems in the prosthetic reconstruction. Attempts have been made to increase the bone height with the placement of autografts and allografts on top of the ridge, but long-term results have been unsatisfactory. Recently an increase of bone in a vertical direction has been obtained in rats, rabbits, and man using expanded polytetrafluoroethylene (ePTFE) membranes. The authors present a case in which an increase of the vertical dimension of the alveolar ridge was obtained using a resorbable freeze-dried dura mater membrane in association with demineralized freeze-dried bone. After a 6-month uneventful healing period the space under the membrane was filled by a tissue with the macroscopic features of bone, and the two implants were almost covered by the newly-formed tissue. An histological examination of a retrieved sample of the newly formed tissue demonstrated the presence of mature bone. It can be concluded that a localized vertical increase of the alveolar ridge may be obtained with the use of a resorbable freeze-dried dura mater membrane.