Healed Edentulous Sites: Suitability for Dental Implant Placement, Need for Secondary Procedures, and Contemporary Implant Designs

Purpose: The purpose of this retrospective computed tomography study was to evaluate bone availability for dental implant placement, frequency of bone augmentation procedures, frequency of anatomical structures that compromise implant placement, and frequency of implant dimensions, and to determine which edentulous sites would benefit from the use of a sloped implant versus a traditional flat design. Materials and Methods: Recorded parameters included the width of the ridge, the buccal and lingual/palatal alveolar bone height in reference to different anatomical landmarks, determination of implant placement, selection of an implant with a flat or sloped top, and need for a secondary bone augmentation procedure. Results: One thousand three hundred seventy edentulous sites were evaluated in 216 patients. Implants could be placed in 60.6% of the total sites, where the coronal portion would be sloped in 59% of sites and conventionally flat in 41%; 39.4% of sites were not adequate for implant placement, where 56.5% needed additional guided bone regeneration procedures and 43.5% required sinus augmentation procedures. The inferior alveolar canal was the most frequent anatomical structure limiting size and/or placement. Conclusion: The study indicates that implants can be placed in slightly over half of edentulous sites without a secondary grafting procedure. The possibility of dental implant placement varied according to the volume and morphology of alveolar bone and related anatomical structures. This decreased from anterior to posterior in both arches. The sloped implant design was beneficial. In addition, the sloped implant design resulted in the placement of a longer implant. Keywords: bone regeneration, clinical research, CT imaging, diagnosis, epidemiology