Mandibular anterior implant placement: recommendations?

The mandibular anterior region can be one of the most challenging regions of the mouth to place implants. It is one of the few regions where the bone volume may decrease as you move apically. It’s also where there can be some strange anatomical features within or entering into the bone, particularly in the midline, as seen in this case. This is more of a problem than the one incisor that has been lost already, all four incisors are weak. If these were all to be removed then the bone in the region would quickly shrink back to the lingual. It’s worth considering removing all three remaining incisors and then placing small diameter (3.3mm) implants in the lateral incisor regions. It would be advisable to flap the anterior region in the process so that the central incisor socket can be re-generated and the labial plate can be augmented, all at the same time. The labial bone plate would need to be perforated with a small round bur prior to the augmentation. This could be done Immediate Placement + Load but it would be less stressful if a provisional adhesive bridge ready to be bonded to the canines was prepared prior to the procedure. The final restoration would be a four unit bridge secured to the two lateral incisor implants. This is a quite complicated procedure, but when performed correctly can be very successful.

I concur with Dr Hunt. My experience in this area, especially in older patients, is that you’re better off replacing all four lower incisors. Basal bone is best, but hard to accomplish in the lateral areas due to somewhat normal cuspid bone/tissue. Placing two implants in the central incisor basal bone sites with lateral incisor pontics will better preserve the existing cuspid bone/tissue.

But in this particular case it would mean that the implants start "way down low", with one much deeper than the other. This would cause aesthetic and functional issues.

Absent a hopeless periodontal diagnosis, removing the rest of the mandibular incisors is a mistake. If you or a colleague in your area is proficient with guided bone regeneration, this site is not difficult to regain the bone in a bucco-lingual dimension. Poor GBR outcomes in this region are usually due to insufficient reflection of the mentalis muscle, inadequate membrane fixation, poor preparation of the recipient site, and/or not releasing the labial frenum during initial healing of the flap. Sadly, predictable GBR seems to be elusive for many clinicians for many reasons. If you or your colleagues are not obtaining predictable results, I would consider a zirconia Maryland bridge (for color reasons) from #23-26 (32-42) or even 22-27 (33-43). Also, there should be minimal contact on these loose teeth, other than in centric, especially in all excursive movements. This is true even if you are going to graft the area. Also, in rebuttal to Dr. Hunt's comment regarding the "strange anatomical feature," the lingual foramen in the anterior mandible is a normal and consistent anatomical feature. This foramen contain an an anastomosis of the sublingual branches the lingual arteries. (McDonnell D, Reza Nouri M, Todd ME. The mandibular lingual foramen: a consistent arterial foramen in the middle of the mandible. J Anat. 1994;184 ( Pt 2)(Pt 2):363–369.)

I feel these are all good comments and possibilities. Doctors have very individual ideas for treatment and there is really no right or wrong. I take a pragmatic approach to treatment planning as to the patients desires and what is predictable for success. 1. if the implant is in the central position; is dictates the future implant positions when the next anterior tooth is removed. 2. not sure but looks like bone loss and apical lesions on other anteriors. 3. removing the other anteriors and placing implants symmetrically will be more satisfying to long term success and prevent many issues of placement and esthetics. 4. I will recommend treatment that I feel good about the long term outcome. 5. I don't feel grafting will be needed and that moving implants slightly vertical will still allow screw retained bridge. 6. I am always concerned with the lingual foreman and wonder why it is not identified with great concern or mentioned more often. Sincerely Leonard