Coordinating Dental Implant Treatment Planning

Dr. Jeffery Lemler is a Clinical Assistant Professor of Surgical Sciences in the Departments of Periodontology and Implant Dentistry at the New York University College of Dentistry. Dr. Lemler is a Diplomate of the American Board of Periodontology and a Diplomate of the International Congress of Oral Implantologists. Dr. Lemler maintains a practice limited to Periodontics and Implant Dentistry at 236 East 46th Street in New York City.

OsseoNews, Inc.(ON): Dr. Lemler what is the most frequent problem you have encountered in coordinating tx planning with the referring dentist?
Dr. Lemler:
Many implant surgeons and restorative dentists fail to adequately communicate with each other and their patients prior to proceeding with reconstructive therapy. Therefore the assessment of functional and esthetic challenges in addition to patient concerns and requirements can be compromised. Dentists need to know and be able to communicate as well as anticipate end results, what and how many procedures are necessary to achieve them, the approximate time involved and, last but not least risks and ramifications. In general, these concepts are successfully applied in full reconstructive cases however; they should not be ignored in partial case reconstructions. Partial reconstructions can require more treatment planning and communication because preexisting conditions have to be accommodated when making final decisions for function and esthetics. In respecting these details, we can avoid situations that are regrettable down the road.

(ON): What are some of the problems you have seen with TX planning?
Dr. Lemler:
It’s a question of perspective, expectations and communication. Surgeons need to be fully aware of how implant placement will affect the prosthetics. There has been much said about the relationship between the surgical placement of implants and prosthetic outcomes. Implant position, angulations and depth are often determined by the location and contour of the alveolar crest. Our present ability to diagnose (via cat scans, diagnostic wax-ups and radiographic/surgical stents) as well as our ability, when necessary, to reconstruct the bone should minimize any compromise in the relationship between the surgical placement of implants and the prosthetics unless agreed upon in advance. These compromises, when chosen, are most likely in order to limit time and/or expense. Surgeons must also consider that with proper positioning, cases may be restored with fewer implants and less risk. In addition, the cases can be divided into segments rather then having to cast full arch frameworks. This should result in fewer headaches and less lab expenses. On the other hand, prosthetic workups have not always taken into consideration tooth root angulations or dilacerations, proximity, required distance between natural teeth and implants, between implants themselves and required widths of implant fixtures.

(ON): Could you elucidate further on what kind of problems you have encountered with diagnostic work-ups and stents provided by the referring dentist?
Dr. Lemler:
To often surgical stents, which have taken time and effort to fabricate, wind up on the surgeons tray rather then as guides for placement in the mouth. In creating the diagnostic wax-up and fabricating stents, factors to consider are not limited to occlusion, interarch height, tooth symmetry to the contra lateral side and esthetics. For example, I find the first bicuspids a classic site of concern when TX planning partial implant cases. Often times the root of canines cants to the distal and the wax-ups have narrow first bicuspids with mesial angulations at the cervical neck. If the surgeon follows the stent, the implant would be placed into or too close to the canine root. If the implant is moved to the distal to avoid the root proximity there will be a significant width discrepancy with the contra lateral side. If the implant is angled to avoid the root it may require more complicated abutment fabrication (which could be more then 15 degrees) and will still have a symmetry problem with the contra lateral side.

(ON): What other problems have you encountered with surgical stents?
Dr. Lemler:
In addition to accurately reproducing the anatomy of the teeth and arch form for the desired definitive restoration, the stent must be stable when placed on the arch or teeth adjacent to the implant site. I recommend clear hard orthodontic acrylic. Many of the suck-down type stents made with thin sheets of acrylic are too flexible and do not fit the remaining teeth or arch accurately. The flexibility can make them useless for the purpose of orientation. They should be clear so that the surgeon can see where and how the osteotomy is progressing both in regards to the supporting bone and the emergence profile. The stent must also provide for adequate irrigation during the procedure.

(ON): Who is ultimately responsible for proper implant positioning in these cases.
Dr. Lemler
Well, the main focus of our discussion today is the need for proper thought, diagnosis, TX planning and communication of the surgeon, restorative dentist and the laboratory in these cases. But, once the implants are in, the foundation is set. It cannot be changed and all the prosthetic/ esthetic outcomes generate from there. Therefore the surgeon must assess the stent and how the guide relates to the idealized prosthetic result prior to the surgical procedure. Finally, we really need additional presentations and articles published to address this topic.