In my last segment, I went through the basic parts and pieces of implants to give some insight into what is a mystery for many. As I mentioned in my last article, unfortunately, with all of the different options and implant manufacturers, doing basic implant-based dentistry can be challenging, and this alone may influence a practitioner’s overall perception of implant-based dentistry.
Now that we have the basic parts and pieces down, we are ready to restore the simple posterior implant that is in the proper position, osseous-integrated, and with a healing abutment/cuff in place and protruding through the gingival tissue. Once you know the implant system and size of the implant (which you should have available to you from your surgeon; hopefully you were involved in the treatment planning process of dental implant), you will need to pre-order or have in stock what you need to remove the healing abutment/cuff, and the appropriate implant impression post.
For your patient appointment, you simply have your impression post and appropriate torque wrench/screwdriver available along with your typical crown and bridge armamentarium. (For the purpose of this article, I will focus on what most practitioners use, which is impression material vs. digitally based procedures). Once your patient is seated and ready and the implant area is verified to be stable, we can begin. We have to first remove the healing cuff/abutment that is protruding through the gum.
For most patients, you will need only topical anesthetic to do this, if that, because there should be a good layer of tissue/healed tissue cuff present around the abutment. This should be accomplished with a manual screwdriver and finger pressure unless the healing abutment was tightened more than this at the time it was placed, or sometimes dried blood can create some extra friction as well.
If so, simply use your torque wrench to gain more leverage and break it free. Once it is loose, have your impression post ready to be inserted, as some tissue can collapse around the implant to some degree once the healing abutment/cuff is removed. (Typically, there are supracrestal circular-type fibers that are not attached and gain support from the abutment). Now that you have the healing abutment/cuff removed and the impression post in place, make sure that it is seated and firmly in place by ensuring that the impression abutment screw is tight, and take a periapical X-ray to see that it is seated and no soft tissue is caught between the impression post and the implant fixture platform.
If all of this good, then you are ready for an impression. For a lot of implant companies, you can either take an impression of the impression post or you can use an impression cap that literally “snaps” over the impression post and allows you to pick the cap up in the impression. If you take an impression of the post alone, a little tip that is helpful for your lab: right before you take your impression, take a little wax or block-out material and block out the head of the impression abutment screw. This will help them be able to index your impression post more accurately in the final impression. Now, you simply take your final impression like you do for standard crown and bridge. (I don’t recommend a triple tray since a lot of impression posts are at or above the occlusal plane, making it impossible for the patient to bite down correctly).
Once you remove your final impression and see that it has captured the details clearly, you can remove the impression post and quickly place the healing abutment/cuff back in place and tighten it with your manual screwdriver with finger pressure. You should be able to take a bite registration and opposing arch impressions along with a shade selection and you are done!
You can now send this off to your lab along with the appropriate information regarding the implant company and size and overall desired end result. On your delivery appointment, you simply remove the healing abutment/cuff, place either your custom abutment or stock abutment, and ensure that it is seated.
This time, you will use your torque wrench to torque or tighten the abutment screw to the appropriate torque that is recommended by the implant manufacturer. You can now try in your crown as you would on routine delivery appointment. If everything fits and looks good, and the proximal contacts are good, then check the occlusion. (Remember, implant occlusion is different because there is no “give” or PDL (periodontal ligament) that helps forgive a premature contact in centric or lateral contacts.) Now that all of this is correct, you are ready to cement your restoration unless you have chosen a screw-retained restoration.
Before seating, make sure that you re-torque your abutment screw, as some will “give” a little from the original torqueing a few minutes earlier, and place something (Cotton pellet, PTFE tape, impression material) to cover the screw head to keep cement from getting in contact with it, possibly interfering with having to tighten/remove it in the future. I will then do a periapical X-ray to make sure all is seated prior to cementation and I will also do one afterwards to make sure no cement is left behind. You then isolate and place a minimum amount of cement into the crown and seat it into place, making sure to remove any and all excessive cement. (Some advocate using a piece of retraction cord gently placed into the sulcus to keep cement from being expressed deep into the implant sulcus.
If this occurs, it will create major issues and increase failure of the implant – so leave no cement or cord behind!) And, you are done! (**While taking parts and pieces in and out of the patient's mouth, use appropriate guards to avoid aspiration of screws, crowns, abutments, etc.)
Jeff Lineberry, D.D.S., F.A.G.D., Visiting Faculty and Contributing Author [http://www.jefflineberrydds.com]