TOPICS OF INTEREST Evaluation of Interarch Space for Implant Restorations in Edentulous Patients:A Laboratory Technique NicolasF. AbuJamra, DDS, MS, 1 M i nosM . Stavri daki s, DDS, M S, 2 and R. BruceM iller, DDS, M S 3 This article describes a laboratory procedure for the visual evaluation of interarch space and its effect on implant prosthesis design. The method is applicable to patients presenting with completely edentulous arches. Silicone impression material is used to form a resilient cast and an external mold from an existing denture. The denture is duplicated using autopolymerizing acrylic resin. The duplicate denture and resilient cast are mounted on an articulator. Spatial relationships of anatomic landmarks can be evaluated, and a quantitative evaluation of available space can be made. The duplicate denture can also be used as a surgical template to direct implant placement. Reference tables are provided to serve as guidelines in the correlation betw een available space and minimum space required for various implant-assisted restorations. J Prosthod 2000;9:102-106. Copyright  2000 by The American College of Prosthodontists. INDEX WORDS: duplicate denture, surgical template, diagnostic aids T HE USE OF implants in the treatment of edentulism has quickly become part of most prosthodontic practices. 1 The reliability, predictabil- ity, and performance of this treatment modalityhave played significant roles in encouraging patients and practitioners to use implants. As a result, clinicians are faced with the need to effectively and efficiently restore osseointegrated implants. Careful consider- ation and deliberate planning become the keys to realizing optimal function and esthetics in implant therapy. The planning phase of implant therapy includes several critical steps. First, the practitioner must understand the patient’s desires and expectations. Second, the practitioner must carefully evaluate the anatomic limitations of the patient. In addition, the type of restoration to be used and the spatial arrange- ment of the patient’s skeletal components must be examined. 2 A diagnostic mounting is of paramount importance for the visualization and evaluation of these relationships. The primary purpose of this article is to describe a laboratory technique that allows for a quick and comprehensive survey of available interarch space when at least one arch is edentulous. This technique also facilitates the process of surgical template fabri- cation. Secondarily, general guidelines regarding in- terarch space requirements for various types of implant restorations are delineated. Technique Diagnostic mounting and tooth arrangement procedures for edentulous patients often require multiple appoint- ments. When a dental patient presents with an adequately restored edentulous arch, a more efficient procedure may be applied. This process can be accomplished in a single visit, and includes duplication of the patient’s prosthesis and transfer onto an articulator. Duplicate dentures also may be used as surgical templates. The process described in this article can be divided into 3 phases: first, duplicating the patient’s denture (steps 1 to 9); second, obtaining transfer records (steps 10 and 11); and finally, evaluating the mounting (steps 12 and 13). 1. Evaluate the patient’s existing denture(s). When proper occlusal vertical dimension, stable tissue adaptation, and acceptable esthetics are present, proceed to Step 2. Otherwise, diagnostic impressions should be made, From theOhi oStateUni versi ty Collegeof Denti stry, Columbus, OH . 1 Pri vatepracti ce, Green Bay, WI . 2 Resi dent, Uni versi ty of Swi tzerland, Geneva, Swi tzerland. 3 Assi stant Professor, Department of Restorati veDenti stry, Prosthodonti cs and Endodonti cs. Accepted M arch 28, 2000. Presented at the annual meeti ng of the Ameri can College of Prosthodon- ti sts, Orlando, FL , November 1997. Correspondence to: Ni colas F. AbuJamra, DDS, M S, 704 South Webster Avenue, Green Bay, WI 54301. E-mai l: PN417@aol.com Copyri ght  2000 by T heAmeri can Collegeof Prosthodonti sts 1059-941X/ 00/ 0902-0009$5.00/ 0 doi :10.1053/ jpro.2000.9106 Journal of Prosthodonti cs, Vol 9, No2 ( June), 2000: pp 102-105 102