298 MINERVA STOMATOLOGICA June 2012 to the coronal crest, not allowing surgical placement of dental implants to support fixed or removable prostheses. 1 Therefore, patients suffering from this phenomenon usually have unstable and non-retentive to- tal prosthetic dentures, which generally re- sults in constant trauma to the oral mucosa, pain, functional limitations (i.e., mastication and speech) and esthetic facial decay. 2 In patients with severe bone atrophy and in locations previously considered unsuitable for implants, many different vertical bone augmentation protocols involving hard and soft tissue handling have been pro- posed in order to maximize the prosthetic procedures. A recent Cochrane systematic review 3 reported that it is unclear which are the most efficient bone augmentation techniques. Osseous grafting, ridge aug- mentation and management of the inferior alveolar nerve are surgical options that en- able acceptance of standard sized dental implants but have serious morbidities, and complications are very common. 3 Recently, this problem has been approached with an innovative concept suggested by Malò in 2003. 4 This procedure, called the All-on-4™, allows to rehabilitate a totally edentulous arch with only four implants placed in the Department of Oral Rehabilitation Tor Vergata University of Rome, Rome, Italy MINERVA STOMATOL 2012;61:298-308 A. POZZI, M. TALLARICO, A. BARLATTANI Unusual anchor pins placement and protocol deviations during computer-based implant placement in a patient with severe mandibular bone atrophy A case report The aim of the study was to describe an unu- sual method to stabilize the surgical template during the treatment of a severely resorbed edentulous mandible by means of computer- guided implant surgery. Pre-operative com- puter-based planning revealed the difficulty to stabilize the surgical template in a 67-year- old healthy woman. A deviation of the origi- nal NobelGuide™ protocol was performed to ensure the stability of the surgical template: four anchor pins were used to stabilize the surgical template, two in the buccal side of the anterior template and two unusual pins were placed in the lingual site. Four straight TiUnite ® Nobel Biocare™ implants were then placed, according to a modified All-on-4™ concept procedure, to avoid graft procedures and to reduce the cumulative chair-side treat- ment time and costs. A temporary restoration was placed immediately after implant place- ment. Three months later a definitive, full acrylic restoration was delivered. Key words: Dental implants - Surgery, compu- ter-assisted - Alveolar Bone Loss. F ollowing tooth extraction residual alveo- lar ridge resorbs. Most of these patients wear complete dentures for long periods, resulting in a cumulative, progressive, and irreversible resorption caused by loss of functional stimulus on the bone. As a conse- quence, teeth, bone and soft tissues are lost. When this occurs in the posterior mandi- ble, the inferior alveolar nerve comes closer Corresponding author: M. Tallarico, Via di Val Tellina 116, 00151 Rome, Italy. E-mail: marco.tallarico@fastwebnet.it MINERVA MEDICA COPYRIGHT® This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies (either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo, or other proprietary information of the Publisher.