Immediate Computer-Guided Implant Placement and Provisionalization Using “All-on-4” Concept: Review of the Technique and a Case Series

Background: Full mouth rehabilitation using an implant-supported prosthess has recently been gaining widespread popularity. The idea of immediate loading of the implants is appealing to both patients and surgeons, and there has been growing evidence of long-term success. The most popular and studied “all-on 4” technique, introduced by Dr. Malo, has been in use for the past 20 years. The goal of this study is to present a new technique developed by nSequence (Reno, NV). The number of implants placed varies, but it still utilizes the “all-on-X” concept. Additionally, it also allows for extraction of teeth at the same visit, as well as immediate computer-guided provisionalization. Through this, it eliminates the need for fabrication of conventional complete dentures as well as a postoperative conversion into a screw-retained provisional.

Methods: 11 nSequence cases documented from 2014-2015 were included in the study. All surgeries were performed by a single surgeon (DCH). Cases that were not immediately loaded or performed by other surgeons were excluded. Patient age ranged from 47 to 75, mean age of 60.1. Total of 6 female, 5 male patients were followed. Teeth were extracted at the time of implant placement on the majority of the patients (9/11). A total of 53 teeth were extracted in the 9 patients and total of 59 implants were placed. All patients received single arch Nobel Active® implants using nSequence bone surgical guides and milled restorations with an incorporated metal bar. Case distribution included 5 mandibular, 6 maxillary cases. Number of implants placed per jaw were either 5 or 6. Failure was defined as primary failure of the implant requiring removal. The success of the the restoration was defined as ability to maintain functioning prosthesis on the placed implants. Follow up time ranged from 6 to 16 months.

Results: 11 cases were followed, 59 total implants were placed. Of these 11 patients, 3 experienced implant failure, two patients had one failed implant, and one patient had two implants fail. Out of the 59, a total of 4 implants failed, giving an implant success rate of 93%. However the provisional restorations were maintained on the remaining implants, yielding restorative success rate of 100%.

Conclusion: The studies performed at our institution appear to support the high success rate quoted in the literature regarding “all-on-4” immediately loaded fixed prosthetic restorations. However we feel that the technique utilizing computer-guided implant planning, as well as design and fabrication of provisional restoration using nSequence technology, improves the already well-established method of full mouth rehabilitation. This method decreases the required chair time in comparison to the conventional fabrication of complete dentures and subsequent conversion to screw-retained provisional. This series reflects our experience with this method retrospectively. New prospective investigations will likely be necessary to provide more generalizable results.

References:

1. Maló P, Rangert B, Nobre M: "All-on-Four" immediate-function concept with Brånemark System implants for completely edentulous mandibles: a retrospective clinical study. Clin Implant Dent Relat Res 5 Suppl 1:2-9, 2003.
2. Malo P, et al: A longitudinal study of the survival of All-on-4 implants in the mandible with up to 10 years of follow-up. JADA 142(3), 310-320, 2011.
3. Patzelt S, et al: The all-on-four treatment concept: a systematic review. Clinical Implant Dentistry and Related Research 16(6), 2014.