Predictable Placement and Restoration of Single Implants
Today’s technologies put greater control in the hands of clinicians
Bradley C. Bockhorst, DMD | Dean Saiki, DDS
Modern technologies, including cone-beam computed tomography (CBCT), digital treatment planning, guided surgery, intraoral scanning, and CAD/CAM prosthetic fabrication, put a tremendous amount of control in the hands of clinicians who place implants. Not only do these tools allow implants to be placed and restored predictably and proficiently, but they also often enable clinicians to do so in a minimally invasive manner. This article offers a review of available technologies that can help provide successful outcomes for single-tooth replacement with implants.
Case selection and treatment planning should begin with a thorough review of the patient’s medical and dental history. Any medical condition or medications that could affect wound healing should be taken into account. It is advisable that practitioners keep abreast of the latest recommendations regarding bisphosphonates and potential complications. When reviewing medications, clinicians should check with the patient regarding use of low-dose aspirin and supplements that can affect bleeding; because they are available over the counter, patients often overlook including them when listing their medications.
The clinical examination is used to determine the amount of available hard and soft tissues. It should include an evaluation of the prosthetic space and the amount of attached tissue in the edentulous area. Also, because guided drills are longer than standard drills, the patient’s vertical opening should be checked. A simple test is to place a guided drill into a handpiece and try it in the mouth. While a limited opening can be accommodated, it is better to be aware of it before going into a guided surgery.
The final decision of whether the patient is an implant candidate should be made after appropriate radiography is taken. The patient should be informed regarding the available restorative options, and, once a treatment plan is agreed upon, the procedure and proper informed consent should be documented.
Documentation of the following case will be used to illustrate how technology can assist with the next stages, including implant planning and placement. A 24-year-old woman presented with a fractured retained deciduous maxillary molar (Figure 1). Her medical history and clinical examination were unremarkable. This type of case can be challenging in that the mesial-distal space is greater than that of a permanent second premolar. The goal was to maximize the bone below the sinus and place an implant parallel to the adjacent interproximal contacts in preparation for a screw-retained crown. Following extraction of the fractured molar, the site was allowed time to heal. Once healing occurred, the patient was sent for a CBCT scan.
CBCT and Digital Treatment Planning
CBCT scans provide a method to obtain a 3-dimensional (3D) view of the patient’s anatomy with a much lower radiation dose than traditional spiral-beam CT scans.1,2 The CBCT scan can then be imported into digital treatment planning software. Vital anatomy such as the mandibular canals, mental foramina, sinuses, and adjacent teeth can be identified (Figure 2).
For partially edentulous cases, a preoperative intraoral scan of the patient or a scan of the model is merged into the planning software. This scan provides the soft-tissue information and will be used as the basis for the fabrication of the surgical guide. Virtual teeth or a scan of the diagnostic wax-up can be added to show the ideal position of the missing tooth. Knowing this information allows the implant(s) to be planned from both the surgical and prosthetic perspectives. A surgical guide can then be ordered and used to transfer the virtual plan to the clinical setting (Figure 3).3,4
Preoperatively, the patient is prescribed antibiotics, chlorhexidine, and pain medication. The antibiotic regimen and chlorhexidine rinses are started 2 days prior to surgery. While there is continued discussion/debate on antibiotics for implant surgery ranging from prescribing no antibiotics to a loading dose to a regimen of 7 to 10 days, at the time of this study the authors’ standard regimen was 10 days of amoxicillin 500 mg three times a day starting 2 days before surgery. The goal is to have the antibiotic on board at least 1 day before surgery. At the time of surgery, appropriate local anesthesia is administered. The patient rinses with chlorhexidine to decrease the bacteria count, and is then draped. A sterile technique is followed and appropriate precautions are taken.
First, complete seating of the surgical guide is verified. Then, utilizing the appropriate key, the pilot drill is drilled to depth. If necessary, the surgical guide can be removed, the pilot drill placed back into the osteotomy, and a periapical radiograph taken to verify the initial site.