Are you using a surgical stent? make your initial penetration with the pilot drill then take a radiograph with either the pilot drill in the hole or a pin. Initial penetration only has to be 5mm that will tell you if your on track angle wise. Then if correction is eneded repeat at the new anglation. The next size drill should follow the new pilot hole if you use slow progression and brace the head of the handpiece so it cant change directions. once the second drill is done all others will easily follow this path. one way to avoid this is use a surgical stent and use the long axis of the adjacent coronal tooth to match the long axis for the pilot drill.

If you are doing an immediate this takes a bit more skill and thought. Look inside of the socket. Actually take the time to suction/irrigate and visually inspect the anatomy. Usually we want to engage some of the lingual bone. Sometimes you need to engage the mesial/distal if the root was dilacerated etc. You need to SEE what you have even it this is NOT an immediate. If you know what is going on in the site, it will make it easier for you to have confidence when changing things because you will know what is going on in the site.

Use of a surgical guide is great but unless you are doing a "guided" surgery it can also make things more difficult. What I mean is don't let the guide be the only tool you use for deciding where the drill goes. The guide will let you know that you are in the confines of the final crown but if you have an extraction socket you also need to know where the bone is you are wanting to engage. If you begin with an angle or position that needs changed because the guide put you there, you need to have the confidence to change it. Just remember your clinical judgement is the best tool and when you are 100% sure where that implant path is; guide the drill to go there.

I learned that using my non-drilling hand to stabilize the head of the drill is VERY HELPFUL. You can resist it moving toward the previous (wrong) path or toward the buccal etc.

We all know that the implant drill has the tendency to "Move into the path of least resistance" so you must make sure you have the path YOU want guided and stable. This will be very helpful. You can have your assitant suction and retract so that both of your hands are guiding the handpiece.

I would place my pilot drill (2.0) to about 5mm like Dr Kurtzman suggested and place a guide pin. Take a radiograph to see where you are and you can also place the stent over the guide pin to see where the implant will end up.

Remember you must use clinical judgement and you have to look at all aspects of the 3 dimensional bone and restoration. If you need to rely on a stent too much you may need to re-visit your surgical experience and techinique. I hope this helps.

Experience will get you to where you have more confidence and you will learn that most of the time you can change angulations even if you already went to full length with the drill. I hope this helps and remember to trust your judgements...We all have been there and we all have to change our angles at times.