What's the best procedures for missing teeth with minimal gap?

Gap: By minimal i think you mean there is a space but not big enough for a tooth. Orthodontics is best because they can widen the space for the appropriate tooth to be replaced or close the space so that no tooth is needed. See an orthodontist for an opinion.

Visit your dentist: There are many variables that would lead to the best option. It is possible that no treatment is best. I would recommend seeing your dentist.

Minor tooth movement: Depending on many variables like why you are missing the tooth, how old you are, your overall dental health etc, you may need to consult with an orthodontist to work with your restorative dentist. Together, they can help create a treatment plan for you that will address your esthetic and functional goals.

Depends: It depends on the health of the teeth and gums, your esthetic goals and financial resources. Furthermore, is the bite off (malocclusion) or do your jaws line up. There are many options for missing teeth which include, braces, dentures, bridges and dental implants. Consult your dentist to determine your options.

No one best: There is no one "best" procedure regarding minimal gaps from missing teeth. Sometime orthodontics, sometimes crowns, sometimes bonding, sometimes no treatment, and sometimes a combination of these methods. You'll need a complete exam and x-rays and then a discussion of treatment alternatives by a dentist who can actually examine you.

You need braces: If you have missing teeth with less than a tooth-sized gap, your adjacent teeth have tipped and drifted, compromising their health and the health of the supporting bone/gums. Have teeth ideally positioned, then the choice of restorations increases, and the result will be more long-lasting.

More info needed: Sometimes a small gap can be closed with Orthodontics, other times with direct bonding of the adjacent sides of the teeth. However, you should see the Orthodontist for an evaluation and if a referral for restorative treatment is needed, they can provide you with the appropriate one. Also, veneers may be used, but they are typically more aggressive and costly. Good Luck.