Clinical case
Extreme vertical and horizontal atrophy combined in posterior mandibular sectors; use of short implants and 2-phase ridge expansion with transitional implants: A clinical case
The objective of this work is the presentation of a clinical case in which we show two surgical techniques to solve the horizontal bone atrophy.
Currently in implant dentistry, we are increasingly faced with cases of extreme bone resorption that force us to implement different surgical dental implant techniques. The coexistence of vertical and horizontal atrophy makes successful resolution of these cases more difficult, as well as having to face these types of more complicated situations with increasing frequency, due to patients demanding implant treatment even in such very severe cases. It is not uncommon therefore to use combined techniques which include ridge expansion or short implants, for example. The following clinical case presented advanced horizontal and vertical alveolar atrophy in the right and left posterior regions of the mandible. The treatment plan included the use of short implants for the vertical atrophy and a two-stage alveolar ridge split to treat the horizontal atrophy.
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 quantity 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 .
removable prosthesis and (B) the critical defects, especially at the antero-inferior level.
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 patients 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 pati ent receiving both procedures: extra-short implants inserted directly into one maxillary quadrant and a sinus lift with conventi onal length implants in the other quadrant. The evoluti on of both treatments in the same pati ent was able to be observed over eight years.
