IM0310

24 I I case report _ piezosurgery Fig. 3b_Clinical initial situation, second case. Fig. 4a_Posterior piezosurgical approach regio 46, second case. Fig. 4b_Postoperative panoramic X-ray, second case. Fig. 5_Postprosthetic panoramic X-ray, second case. implants3_2010 fixed minimal-invasive with preferably less bone augmentation effort. In as short a timeframe as possible the osseointegrated implants should be ready for screwed implant-supported bridges in both jaws. After an extensive consultation, study casts and a CT scan the patient was treated in local anaesthesia as follows: In the mandible tooth 43 was extracted, four implants were inserted inter- foraminal and regio 36, 46 each one implant was placed post piezosurgical transposition of the in- ferioralveolarnerve.Inthemaxillatheteeth12,21, 23, 25, 26 were extracted and again sic implants were anchored (Figs. 3a, 3b, 4a & 4b). Each Anky- los® plus implants (DENTSPLY Friadent, Germany) were used. Comparison of the postoperative (Fig. 4b) and the postprosthetic (Fig. 5) panoramic X- ray, 5 months later, impressively clarify the fast bony regeneration in both fenestration locations. An about eight months lasting, less than 1 cm mean diameter measuring aera of minor hypaes- thesia on the left chin side, did not impair patient satisfaction with the final reconstruction out- come. _Discussion Severe resorption of the posterior mandible poses one of the most difficult restorative chal- lengesindentalimplantology.Boneaugmentation procedures (e.g. bone grafting or alveolar distrac- tion) may increase the amount of bone in deficient areas. But these treatment options are costly, time-consumingandinvolveanelevatedriskofin- conveniences and complications. Nerve repositioning has proved as an excellent alternativetoaugmentationproceduresforplace- ment of dental implants. The technique permits implant therapy in atrophied lower jaws with in- sufficient vertical height superior to the mandibu- larcanal.Integrationoffixedbridgesinsteadofre- movable appliances is enabled with just one surgi- cal session even in instances, where—as described in the first case—only 2 implants can be installed interforaminal. Safety and precision of the relocation of the in- ferior alveolar nerve have been further improved by the use of a new approach, the ultrasonic os- teotomy. Piezoelectric surgery maintains blood- free sites and allows to perform precise linear and curvilinearosteotomieswithouttheriskofcutting soft tissues. Bone drills and oscillating saws represent more aggressive cutting instruments which are rela- tivelydifficulttocontrol(e.g.duetothegeneration ofmacrovibrations)andwhicharemoredamaging to soft tissues. Compared with these traditional cutting in- struments the main disadvantage of piezosurgery concerns the increase in the operating time. Independentoftheosteotomytechnique,nerve damage can be the result of an overstretched mu- coperiosteal flap in the premolar area to achieve optimal view in the operating field. Especially with piezosurgery overstretching of the mental nerve can be reduced by creating smaller bone fenestra- tions. Touchingtheinferioralveolarnervewithpiezo- electricinsertsresultsatmostinrougheningofthe epineurium without harming deeper structures,8 as far as heat injuries are prevented by an appro- priate handling of the ultrasonic device. Referring to the author’s experience it seems to be favourable to place particulated bone around theimplantsjusttopreventadirectnerve-fixture- contact and in order to aid the subsequent os- seointegration. Additionally, or at the very least alone, the bone window should be covered by a re- Fig. 4bFig. 3b Fig. 4a Fig. 5