When I first began treatment planning implant therapy as a resident, I simply referred the patient to the surgical dentist and waited for him/her to return in a few months with a healing abutment. If this sounds like you, you are missing an opportunity to contribute to the cosmetic and functional success of the final treatment outcome, even if you work with a great surgical dentist.
As a restorative dentist, I am frequently the member of the dental team that introduces the concept of implant therapy to a patient. But before I refer the patient to the surgical dentist, there are several pieces of information I should collect as part of my examination. In this post I will discuss the evaluation of the available space for the implant and crown.
Feel free to download The Chairside Implant Space Planning Guide below for your own purposes. It is not meant to replace a 3-D scan or surgical expertise in determining implant placement. Rather, this is merely a guide for the restorative dentist to begin to evaluate available restorative and surgical parameters during the diagnostic phase.
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(1) Mesio-Distal
(a) Measure the mesial-distal space for the crown clinically or from study models. If the space is in the esthetic zone, it should have the same M-D width as the contralateral tooth. If not, consider orthodontics or restorative means to equilibrate the space with the contralateral tooth. If the contralateral tooth is missing, use the average values from the chart, “M-D crown.”
(b) Measure the mesial-distal space for the implant via radiographs or a 3-D scan. There should be 3.0 mm between the implant and an adjacent implant or 1.5 mm between the implant and an adjacent tooth root. Once subtracting those measurements from the total space, ensure that there is enough space for an implant which is roughly the same diameter of the contralateral tooth. If the contralateral tooth is missing, use the average values from the chart, “M-D crown 2mm below CEJ.” If there is insufficient space, consider orthodontics and/or a smaller diameter implant.
(2) Bucco-Lingual
Evaluate the contour of the buccal bone clinically or on a study model. The implant must be placed with at least 2.0 mm of bone facial to the surface of the implant. If there is uncertainty, evaluate the bone on a 3-D scan. If there is insufficient bone, a graft of hard and possibly soft tissues will be necessary.
(3) Apical-Coronal
(a) The implant platform is typically placed at the level of the osseous crest. In ideal circumstances in the absence of periodontal disease and/or trauma, this should also be 3.0 mm apical to the free gingival margin to provide adequate running room for development of emergence profile. This would also be 2.0 mm from the adjacent tooth’s CEJ. If these measurements based on these landmarks are not coincidental, consider periodontal, orthodontic, or restorative therapies to resolve the discrepancy.
(b) Ensure that the opposing tooth has not supra-erupted into the space for the final restoration. If it has, additional restorative procedures such as enameloplasty or a full coverage crown may be necessary to restore the occlusal plane. It is always best to inform the patient of this necessity before implant therapy is initiated.
Obviously there is a lot more that goes into treatment planning implant therapy. But this should hopefully aid you in space management during the diagnostic phase.