Missing Lower 6: How to Approach this Case?

There is space for an implant but the real issue is what will happen in the area after implant and crown are placed. Because of the angulation and the path of insertion there will be a food trap area between the crown and 7 which will constantly annoy the patient and probably end up with perio disease of 7. I also note slight over eruption (as best I can see from the OPG) of the opposing tooth which might also need attention. There are several way you could consider treating this. • Do nothing • Shave some enamel of the mesial of 7 • Crown the 7 and realign the mesial aspect to allow more space • Best treatment – orthodontic uprighting of 7 (and 8?) Ortho would be by far the best option but I am not sure about the lower 8. Clearly the upper 8 should be removed and possibly there will be some bone resolution of the distal bone defect of upper 7. However possibly the upper 7 will also be lost due to perio (it really needs a clinical examination to know more). If the upper 7 is also lost then the question is how to proceed. Will the patient want an upper 7 implant also or will they be happy with just the remaining upper 6. Depending on the answers to these questions, it may be that the lower 8 should be removed (probably) which would make ortho easier for the 7. I realise this is a convoluted answer but the real point I am trying to make is that your question is not as simple as knowing what to do with the lower 6 implant. The situation needs to be considered as a whole and the patient needs to be informed of the various consequences and options available. Since extraction of the upper 8 is an easy decision but the extraction of lower 8 not so, I suspect the patient will elect not to have upper 7 or lower 8 treated and so I would then be inclined to not recommend any treatment of the lower 6 area at this stage.

Dr Gerke has some great suggestions, but I would not be comfortable in crowning the first molar. To get it "upright" would require preparing the tooth down to where the pulp was endangered and then it would look a little weird Uprighting the molars with orthodontics sounds so obvious, but this would be almost impossible with this hefty and well anchored third molar remaining in place. You would probably succeed in flaring the anterior teeth instead. It would be much better to remove the third molar along with the maxillary third molar, then it would be relatively simple to upright the first molar, though one has to ensure that the tooth does not erupt at the same time which would prevent the tooth from moving. In this case, the Curve of Spee has increased with the maxillary first molar supra-erupting down into the space left open when the mandibular first molar was removed, so this tooth will require some occlusal adjustment to put it back into line. Once the space has started to open, it would be useful to get an implant "in" relatively early as this can then be used as anchorage for the orthodontics. In short, to get a good result here, needs careful planning and good execution, otherwise things can quickly get out of control.

Orthodontics can achieve a good result if anchorage and time are used correctly. The anterior segments (bicuspids and canine) are stabilized with Skeletal anchorage such as a TAD and the both molars are protracted to become first and second molars. The opposing molar must be intruded to correct plane of occlusion or modified. The issue is time of treatment required. Examples of this approach are found in the JAOS written by JC Echeverri or at our website Echeverri Dental.com

There is no question in my mind that this situation requires extracting the upper and lower third molars, and then doing orthodontics to upright the lower second molar......pay attention to the second upper bicuspid with deep caries (25)...is it vital? An attempt to intrude the upper first molar could be taken orthdontically…… or after the lower second molar is uprighted, and an implant placed in the #36 implant position,,,,,,,then after four months, a temporary crown is placed on the implant...… by over building the occlusal height, it could aid in pushing up #26

I agree with all that has been said. My previous comments about enamel reduction or a crown were comments about possible treatments but not what I would recommend. The important answers we need to know are: • What age is the patient – if he/she is 40 then the treatment recommendations would be considerably different to a patient who is 70. • What does the patient want? If the patient is 70 then clearly they have done well to date and there would be a reasonable argument to do nothing in regards to a lower implant. However the recommendation could be different if the patient is 40. As mentioned, all the options need to be discussed with the patient who should decide on the merits of each option. As I previously alluded to, I would suggest the upper 8 is removed and then the resultant outcome in regards to the upper 7 should be reviewed. In my opinion, until the long term outcome of the upper 7 is ascertained, it would be unwise to commit too much to treatment of the lower molars (although I acknowledge the lower 8 will be redundant and therefore possibly major emphasis should not be placed on retaining that tooth). However I always consider what the patient might think; would they appreciate a recommendation to extract a lower 8 which is giving no trouble at the moment when it is the upper 8 which is causing an issue? Thus the ultimate treatment has to depend on what the patient thinks, which will be determined by the prevailing circumstances.

Slight enameloplaty of molar. Place implant and restore with a cement retained crown. A screw retained crown may be difficult due to draw. Please post CBCT if you have one with different views. Thanks.

It’s nice to be able to look at the casts

Is the upper 2nd premolar ok? There is a big shadow distally? Ortho is the way to go imo...you could quite easily bring the lower molars forward into the space with enough patience and grown the bone..upper 1st molar looks a bit overerupted ....