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184 rev port estomatol med dent cir maxilofac. 2019;60(4):175-188

tion B – placing four implants between the mental foramina, therapeutic options
is a simple and predictable option. The use of short implants Two treatment options are suggested for these patients, using
is currently considered predictable, and in several cases, Op- short implants in the anterior area versus major augmenta-
tion A might be more favorable by placing a short implant in tion. Both the anterior and posterior areas have a minimum
the molar region since it avoids cantilevers and allows a sec- height and width, challenging the implant placement.
ond molar occlusion. 50,51
Option A – Placement of four short straight implants (4 or 6
Mandible CCIV mm) equidistant in the anterior region. The two anterior im-
Anterior – Advanced resorption (height >8 mm and <12 mm; plants are placed in the lateral incisors position and the two
width >6 mm) remaining in the first premolars position at a safe distance
Posterior – Severe resorption (height < 4mm or width <6 mm) from the mental foramen.
Advanced bone resorption is confirmed in the anterior region Option B – A more invasive surgery to augment the height and
of the mandible. The bone height measured from the osteoto- width of the mandible. In this option, an extraoral autoge-
my level, with a >6-mm crestal width, to the inferior border of nous bone graft is suggested (hip, rib, calvarium). Four or six
the mandible is >8 mm and <12 mm. The posterior region pre- axial implants are placed in the same positions and with the
sents severe bone resorption. The bone height measured from same lengths as referred in the Mandible CC II Option A or B
the alveolar crest, with a <6-mm crestal width, to a 2-mm safe scheme.
distance from the mandibular canal is <4 mm. Option C – Similar to the previously described removable op-
tions for Mandible Classes I, II, III and IV using two or four
therapeutic options short implants.
In this class, the posterior bone height (<4 mm) precludes the
placement of short implants, unless vertical bone regenera- deciding factor
tion procedures are performed. Hence, two options for the The surgeon’s expertise should be the main deciding factor
surgical approach are described. for performing one of the previously described techniques
since a severely atrophic mandible presents high risk for po-
Option A – Placement of four equidistant implants in the an- tential complications, mainly mental nerve injury, mandibu-
terior region of the mandible. Two straight implants are placed lar fracture or hemorrhagic accidents. Both therapeutic op-
in the lateral incisors position and the two other implants are tions are described in a 10-year follow-up randomized
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placed tilted at a 17° angle with entry points coincident with controlled trial. According to this study, the four short im-
the mental foramen or slightly posterior to it (Figure 5, Figure plant option presented a higher cumulative survival rate
10, Figure 11). (98.8%) compared to the augmentation procedures (88%). Less
Option B – Vertical bone grafting in the posterior region for morbidity in the patient and retreatment survival were also
the placement of two implants in the position of the first more favorable in this option. More recently, a systematic re-
molar. The length of the implants should range from 6 to 8 view and meta-analysis that evaluated vertical ridge aug-
mm. Regarding the interforaminal region of the mandible, mentation procedures in the atrophic mandible recognized
the surgical approach is the same as previously described in that, if 4 mm of vertical augmentation is needed, any tech-
Option A. nique – inlay block grafting, onlay block grafting or osteogen-
Option C – Similar to the previously described removable op- esis distraction – should be predictable in healthy patients. 53
tions for Mandible Classes I, II and III.

deciding factor Discussion
Placing four implants in between mental foramina, as men-
tioned earlier, is a simple and predictable option and is con- The aim of this paper is to propose the first patient-cen-
sidered the most favorable option for this level, compared to tered decision-aid tool for fixed and removable full-arch re-
Option B with vertical augmentation of the posterior mandi- habilitation of the maxilla and the mandible. This type of
ble, to place an implant in the molar area. Individual pa- classification system should not be perceived as a clinical
tient-related factors must be analyzed to decide the suitable algorithm or a decision tree. It should provide a justified
number of implants and the risk/benefit ratio associated with suggestion of a possibly preferable treatment option but not
bone graft procedures on the posterior mandible. dictate it.
Contrary to previous descriptions found in the literature,
Mandible CCV this classification system was developed focused on patient
Anterior severe resorption (height <8 mm or width <6 mm) individuality rather than on the implant system technique.
Posterior severe resorption (height <4 mm or width <6 mm) Previous classifications have emphasized the prosthodon-
A severe bone resorption pattern is observed both in the an- tic-driven implant concept. Papadimitriou et al. proposed a
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terior and posterior regions. In the anterior region, the bone classification based on 100 CBCT analyses previous to implant
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height measured from the osteotomy level, with a <6-mm planning with a software application. Although this classifi-
crestal width, to the inferior border of the mandible, is <8-mm. cation expressed four different levels of jaws atrophy, it was
As described in Mandible CCIV, the same values are seen in brand-specific and implant-design-specific (Straumann Tis-
®
the posterior region. sue level). Despite its long-term clinical outcome assessment,