Dr. Paolo Malo from Portugal is the researcher and creator of one of the most popular surgical and prosthetic technique, we are talking about the “all-on-4”. This technique has been proven scientifically over the past two decade, hundreds of scientific articles have validated its results. The value in it comes from been able to place implants in atrophic mandibular and maxillary arches without the need for bone augmentation procedures such as lateral windows and block grafts.
A draw back to this technique is that the prosthesis usually results possessing 10 units since cantilevering must be avoided. To solve this situation and be able to add 1st and 2nd molars we suggest to place two short implants in the posterior region either in the retro molar or the tuberorisity. The following
Case shows how we can modify this technique from a surgical perspective Respecting all principles established by Dr Paolo Malo yet added a component that allows us to have a prosthesis with 12-14 units without cantilevering.
A 61 year old healthy Latin female presents to our clinic with a broken molar that supports a removable partial and 6 anterior units with moderate-advanced periodontitis and periapical pathology (fig 1)
3D images from a Ct-scan (Carestream, USA) were used to plan the case using a “Modified all-on-4”.
A traditional “all-on-4” will be performed in the intraforamina region and two short will be placed on the 2nd molar site (fig 2).
Digital panoramic view of pre-op case. An “all-on-4” is indicated since the resorption of the alveolar ridge has approached the Inferior Alveolar Nerve and is not possible to place implants in the posterior region without resorting to block grafts (fig 3).
Autramatic extraction is performed, note bucco-lingual resorption of the posterior areas (fig 4).
Full muco-periosteal flap is raised from molar to molar. Bony topography is irregular and not suitable for implant placement without full arch regularization (fig 5).
The alveoloplasty is achieved with a large bone cutter bur (Meisinger, USA) at 35,000 RPM utilizing a straight hand piece and copious irrigation (fig 6).
Care is taken to create a flat occlusal alveolar table and avoid creating a chamfered ridge (fig 7).
The alveoloplasty will allow the prosthesis to sit on a stable occlosal table, creates prosthetic room for abutments and simplifies the surgery (fig 8).
A bone caliper (Salvin, USA) is used to verified that we have achieved an occlusal table of 7mm which will allow us to place RP implants. Note the exposed mental foramen (fig 9).
The initial bone perforation is achieved with a starter drill or lance following the angled line drawn on the bone (fig 10).
Guide pins are in place , this allows for visualization and final correction of angulations and spacing. Remember that 80% of the work is done with the lance and the pilot drill, this is similar to non-surgical endodontic where most of the work is accomplished with 6-10 files (fig 11).
Bone D2, Dr. Misch’s osseous classification, calls for site under-preparation. We select a 3.75 self tapping implant (Noris Implant System, Israel) and our last drill is 3.1mm (fig 12).
All implants are placed flush with the alveolar ridge, we have achieved perfect bio-mechanical distribution utilizing the “Modified all-on-4” surgical technique (fig 13).
Pre-operative panorex shows the severe atrophic ridge resorption (fig 14).
3D image shows the pre-surgical “modified all-on-4” planification (fig 15).
Post-operative panorex reveals a “all-on-4” plus two short implants anterior to the 3rd molars. This technique calls for thinking out of the box and understanding that Dr. Mongalo’s phrase is true in almost all cases “ No bone, no problem” (fig 16).
Live Implant training institute
The case of the month was performed by an attending USA licensed dentist under direct supervision of Dr. Mongalo while attending a 7 day surgical externship at LIT.
For more information on these courses contact us at www.liveimplants.com Or call 786-249-4510