Clinical accuracy of flapless computer-guided surgery for implant placement in edentulous arches
Title:
Clinical accuracy of flapless computer-guided surgery for implant placement in edentulous arches.
Author/s and their location:
Vieira DM, Sotto-Maior BS, Barros CA, Reis ES, Francischone CE.
Issue:
International Journal of Oral Maxillofacial Implants, 2013 Sep-Oct;28(5):1347-51.
PURPOSE:
Although flapless computer-guided implant placement provides important benefits, deviations from the planned implant placement in the edentulous arch may pose significant risks. This study evaluated the reliability and accuracy of a flapless computer-guided surgical approach.
MATERIALS AND METHODS:
Computer-generated preoperative implant planning was compared to actual placement by cone-beam computerized tomography (CBCT) scanning of patients before and after surgery.
A well-fitting complete denture or optimized prosthetic tooth arrangement was used and converted to a radiographic template. Prior to scanning, aesthetics and functional aspects were checked clinically.
The implant positions were virtually determined by the implant planning software relative to the bone structure and prospective tooth position.
After implant placement, new CBCT scans were obtained for each subject. Software was used to fuse the images of the planned and placed implants, and the locations and axes were compared. The normality of the data distribution was evaluated by the Kolmogorov-Smirnov test. Mean values were compared between groups based on the upper or lower jaws with the t test for independent samples. The level of significance was fixed at 5%.
RESULTS:
Sixty-two implants were placed in edentulous arches with stereolithographic surgical guides in 14 patients. Damage due to implant placement was not observed in any critical anatomical structure.
Compared to the planned implants, placed implants showed mean and standard deviation linear measurements at the cervical, middle, and apical implant portions of 2.17 (± 0.87), 2.32 (± 1.52), and 2.86 (± 2.17) mm, for the maxilla, and 1.42 (± 0.76), 1.42 (± 0.76), and 1.42 (± 0.76) mm, for the mandible, respectively.
The angular deviations were 1.93 (± 0.17) and 1.85 (± 0.75) degrees for the maxilla and mandible, respectively. The linear deviation differed significantly between the upper and lower jaws, but the angular deviation did not.
CONCLUSION:
Flapless computer-guided surgery MAY be a viable treatment option for rehabilitating the edentulous arch.
Dr. Brown’s Opinion:
Currently we utilize 3D Virtual Planning for complex edentulous cases.
Fully guided implant surgical guides that anchor to the underlying bone utilizing lateral screws for completely edentulous patients
Tooth supported guides are also very key with partially edentulous patients
This study investigated the accuracy of "Tissue-supported guided surgery". It is evident that a deviation in implant locations by 2.5 mm on maxilla and 1.5 mm on mandible for completely edentulous arch based on the data. This causes one to reconsider using any surgical stent that is not anchored to the underlying bone or supported by teeth. It should also be noted that even though a deviation of angle was observed of 1-2 degrees this is considered negligible.
A good prosthetic understanding of where the final restoration will be coupled with a strong background in dental anatomy is the only way to ensure predictable results.
I encourage all individuals who are beginning to place implants to:
Get a pre-op CBCT
Have a surgical guide made that is either support by teeth or anchored to the underlying bone.
If you are interested in finding out more about this topic or referring a pt please contact me directly at Drbrown@brownprosthodontics.com or by phone at 202-244-2865
References:
Edward K. Brown Jr, DDS,DMSc