Prosthetic rehabilitation of the edentulous maxilla is known to be challenging and requires meticulous planning. The purpose of this article is to describe a novel classification system, the Lip-Tooth-Ridge (LTR), that offers a guidepost for treatment planning the edentulous maxilla for fixed or removable prostheses. This tool will help clinicians identify the final prosthetic design and will provide a case-specific risk assessment guide regarding two different areas. A high (HER) or low (LER) esthetic risk will be determined based on lip dynamics, as well as a high or low structural risk according to the prosthetic space availability.

Bei zahnlosen Kiefern greift man in den meisten Fällen auf eine konventionelle Vollprothese zurück. Bei höheren Ansprüchen bieten sich implantatgetragene totale Brücken an, die aus funktionaler, biomechanischer und ästhetischer Sicht natürlicher sind. Das Konzept der Osseointegration hat sich hier als nützlich und berechenbar erwiesen. Da implantatgetragene Metallkeramikbrücken nicht für alle zahnlosen Patienten geeignet sind, ist hier ist eine genaue Behandlungsplanung unter Berücksichtigung des Zustandes des Patienten durch den Zahnarzt und sein Team unabdingbar. Der vorliegende Artikel zeigt Behandlungsvarianten auf und dokumentiert diese anhand eines konkreten Falls. Keywords: Zahnlosigkeit, Implantatprothetik, Totalprothetik, Behandlungsplanung, implantatgetragene Metallkeramikbrücke, zahngetragene Metallkeramikbrücke

Common complaints associated with the Kennedy Class I (bilateral free end) and Class II (unilateral free end) removable partial denture situations are lack of stability, minimal retention, and unesthetic retentive clasping. Some of the same complaints have been reported for implant overdentures with only anterior implants. Starting in 1995, 10 of these patients were treated at the University of Washington with posterior osseointegrated implants to provide stability and/or retention of the removable prostheses, eliminating the need for clasps when possible. This article describes implant alternatives and prosthesis designs and presents a follow-up clinical evaluation of at least 1 year consisting of patient satisfaction, radiographic examination, and soft tissue health. Two groups were evaluated. Group 1 included patients whose implants were used as vertical stops for mandibular distal extension prostheses. Care was taken to ensure that the implants were not loaded laterally by creating a single-point contact at the center of a modified healing abutment. In these cases, sufficient retention was available from the anterior teeth and/or implant abutments. Group 2 included patients whose implants required retention because of lack of adequate tooth abutments. In those cases, a resilient type of attachment was used, which allowed for a small divergence from the path of insertion. Results indicated consistent increased satisfaction in all patients, minimal component wear, no radiographic evidence of excessive bone loss, and stable peri-implant soft tissues.

Tightening of the screws in implant-supported restorations has been reported to be problematic, in that if the applied torque is too low, screw loosening occurs. If the torque is too high, then screw fracture can take place. Thus, accuracy of the torque driver is of the utmost importance. This study evaluated 4 new electronic torque drivers (controls) and 10 test electronic torque drivers, which had been in clinical service for a minimum of 5 years. Torque values of the test drivers were measured and were compared with the control values using a 1-way analysis of variance. Torque delivery accuracy was measured using a technique that simulated the clinical situation. In vivo, the torque driver turns the screw until the selected tightening torque is reached. In this laboratory experiment, an implant, along with an attached abutment and abutment gold screw, was held firmly in a Tohnichi torque gauge. Calibration accuracy for the Tohnichi is ± 3% of the scale value. During torque measurement, the gold screw turned a minimum of 180 degrees before contact was made between the screw and abutment. Three torque values (10, 20, and 32 N-cm) were evaluated, at both high- and low-speed settings. The recorded torque measurements indicated that the 10 test electronic torque drivers maintained a torque delivery accuracy equivalent to the 4 new (unused) units. Judging from the torque output values obtained from the 10 test units, the clinical use of the electronic torque driver suggests that accuracy did not change significantly over the 5-year period of clinical service.