Clinical case
Atrophic posterior maxilla: sinus elevation with lateral approach Vs. Extra-short implants. Clinical case with eight years of follow-up
Vertical bone loss in the posterior maxillary sectors is a frequent occurrence after tooth extraction. These areas can often be rehabilitated using regeneration techniques or by opting for a more conservative approach with short implants.
The present clinical case shows bilateral rehabilitation with two different techniques: sinus lift and the insertion of short implants, with a follow-up of 8 years where both techniques have achieved equally predictable results.
Approaching the posterior sectors of the maxilla with extreme resorption is a common situation in dental practice. The loss of antral teeth produces pneumatisation of the maxillary sinus, which progressively occupies the space corresponding to the dental roots, in some cases leading to complete atrophy and in a residual bone height of 1-2 mm aft er the dental socket heals. This pneumatisation occurs over ti me aft er tooth extraction, but is unpredictable in terms of quanti ty and speed, and appears to be slightly related to the type of relationship that occurs between the apex and the sinus. This relationship was described by Sharan and Madjar in 2008, who established a classification with greater pneumatisation is expected in its types 3 and 4 (Figure 1)1 .
the floor of the maxillary sinus.
Type 0: The root is not in contact with the sinus cortex.
Type 1: The sinus cortex is less convex and makes slight contact with the upper area of the root apex.
Type 3: The sinus cortex describes a curve of lower convexity and the apices of the roots of the antral teeth project into the sinus.
Type 4: The sinus cortex is less concave surrounding the apices
of the antral teeth, and there may be a slight prolongation of the root apices inside the sinus.
Until the arrival of short and extra-short implants, the only alternative treatment in these cases was sinus elevation (laterally or transcrestally), and there were different techniques and procedures for this. The attempt was to gain the lost bone volume and the subsequent insertion of conventional length implants at this level2-6.
The development of short implants and the entire technique for their use sometimes allows the insertion of implants in large posterior vertical atrophies of the maxilla, avoiding sinus elevations.
Nowadays, most authors accept short implants to be those with a length less than 8.5 mm, although there are many cases of lengths well below this figure7-9. Extra-short implants, meanwhile, have more variation in terms of their classification; although the latest articles published consider extra-short implants to be those with a length less than 7 mm10-12. These shorter implants mean less morbidity for pati ents, at the same ti me as it is now possible to rehabilitate pati ents who may refuse to have additional techniques performed. These are sinus elevation and even more complex techniques which may be contraindicated in these pati ents for different medical reasons13-17. These short and extra-short implants can be inserted in the atrophic areas of the maxilla directly without displacement of the lower sinus cortex and without therefore having to manoeuvre the maxillary sinus. The main surgical challenge with this technique is to achieve implant stability, since generally in these cases we are faced with little remaining bone height and with high porosity18-22. Therefore, the establishment of a careful surgical protocol based on drilling into the receptor bed depending on its condition is key to the success of these treatments13-17.
The clinical case described is of a patient receiving both procedures: extra-short implants inserted directly into one maxillary quadrant and a sinus lift with conventional length implants in the other quadrant. The evolution of both treatments in the same patient was able to be observed over eight years.
