In patients having congenitally missing maxillary laterals, the orthodontist wishes to keep a space,that could be restored later. How can we determine the space required?
if only missing one, you can compare with the length of the other lateral. if both missing, you have to use bolton ratio and make sure the midline is a line
Only other factors that might be worth consideration is If contralateral tooth is peg / diminutiveare and/or if the space is likely to be restored at any time with an implant? If so, may be worth getting a restorative/ implantologists opinion to maximise bone support, appropriate root approximation and soft tissue profile? Similar input might be helpful for a bridge as well (e.g minimising metal show on adhesive bridge, sufficient space for restoration of contralateral tooth)?
Be aware of your biological spacing. Opinions vary when it comes to preferred distance between an implant and the adjacent teeth. Trying to idealize the implant angulation, you need to be cautious not to perforate the buccal plate. The spacing in the palate should not be an issue. I prefer 1.5 - 2.0 mm at the predicted gingival emergence of the custom abutment to allow for a nice healthy maintenance of the papilla. Also, it is nice to have the implant to abutment connection at least 3 mm subgingival after healing. I have found that in most of my cases I will lose about 1 mm of gingival height during healing when using a stock or a custom healing cap. By using virtual placement software, there will be tools available to help ensure there is plenty of space and help you prevent a compromised result. You should also be careful with the root angulation of the centrals and cuspids, this distance may be a limiting factor.
I guess to answer your question directly...I prefer a 4 mm diameter implant with the interproximal distance (at the contact areas) between the cuspids and central being 7.0 to 7.5 mm.
How old is the patient ? are the teeth still erupting? If the patient is adult how health are the supporting structures as these may influence the loss of attachment in due cause.and What is the rational for opening up the space early and puting in a fixed spaceretainer?. Why cant the teeth be left in the natural balnced sted and open up when the patient is ready? taatebe ed . There is no measurement by the orthodontist hence no refernce point.e