Evolution of surgical guidance in implant dentistry

When modern dental implantology was introduced in the early 1980s, implant placement was often carried out based only on available residual bone. Several studies have clearly demonstrated that implants placed in this manner often emerge in a buccal or lingual position, ending with arduous, or even impossible, aesthetic problems to solve.1 On the other hand, it has been shown that implants that are not working in their long axes were exposed to detrimental lateral forces, ending with numerous biomechanical problems and even breakages.2 Owing to too many associated problems and the functional compromises of the final prosthesis, new concepts were developed and new methods produced by first considering the prosthesis rather than the surgery. Thus the concept of ‘Prosthesis driven implantology’ was born.

In the early days, clinicians who believed in this concept mostly depended on diagnostic wax-up and/or surgical templates made on hard gypsum surfaces of master casts3^,4 (Figures 1 and 2). Although these templates could provide prosthetic guidance, they could not take into consideration the anatomy of the underlying bone.5 It was also discovered that the hard surface of casts may not entirely replicate the soft tissues of the oral cavity, and therefore this method may not be as accurate as necessary for some treatment purposes.