Table 1: Main characteristics of the studies selected.

Study Study Design Population Implants Brand Implants Number (size length x width) Augmentation Procedure Results Conclusions
Felice et al. 2010 26 RCT N = 60 patients
F/M gender ratio: 38/22
Age range: 40-83 years
NanoTite - Biomet 3i (Palm Beach, USA)) 60 short (7 x 4 mm)
61 longer (10, 11.5, 13, 15 x 4 mm)
Vertical augmentation of mandibles with inorganic bovine bone blocks. IF: 3 Longer and 1 Short
MBL:
Short 1.79 + 0.54 mm
Longer 1.65 + 0.42 mm
Interpositional bovine block grafting and placement of short implants achieved good and similar results. Short implants might be a preferable choice when the bone height is limited as the treatment is faster, cheaper and with less morbidity.
Esposito et al. 2011 28 RCT (split mouth design N = 30 patients
F/M gender ratio: 17/13
Age range: 37-70 years
MegaGen Implant Co. (Gyongbuck, South Korea) 60 short (5 x 6 mm)
68 longer (10 x 6 mm)
Interpositional bone blocks in mandibles or particulated bone in augmented maxillary sinuses. IF: 2 Longer and 1 Short
MBL:
Short: 1.30 + 0..57mm
Longer: 1.48 + 0.50 mm
All techniques provided good and similar results up to 1 year after loading, however, 5 mm short implants might be a preferable choice to augmentation procedures
Pistilli et al. 2013a 29 RCT (parallel group design N = 80 patients
F/M gender ratio: 55/25
Age range: 57-75 years
MegaGen Implant Co. (Gyeongbuk, South Korea) 68 short (5 x 5 mm)
68 longer (11.5, 13, 15 x 5 mm)
Equine bone blocks in mandibles or particulated porcine bone in augmented maxillary sinuses. IF: 2 Longer and 1 Short
MBL:
Mandible – Short: 1.18+ 0.29mm
Longer: 1.36 + 0.28mm
Maxilla – Short: 1.16 ± 0.30 mm
Longer: 1.53 ±0.59 mm
One year post loading, 5 x 5mm implants achieved similar (in the maxilla) if not better (in the mandible) results than longer implants placed in augmented bone
Pistilli et al. 2013b 8 RCT (split mouth design) N = 40 patients
F/M gender ratio: 19/21
Age range: 55-85 years
Southern Implants (Irene, South Africa) 80 short (6 x 4 mm)
91 longer (≥10 x4 mm)
Equine bone blocks in mandibles or particulated porcine bone in augmented maxillary sinuses. IF: 3 Longer
MBL:
Mandible – Short: 1.33 + 0,22 mm
Longer: 1.44+ 0,21mm
Maxilla – Short: 1.41 + 0,31 mm
Longer: 1.53 + 0,29 mm
Short implants may be as effective, if not more effective, than longer implants placed in augmented posterior jaws
Thoma et al. 2015 30 RCT (parallel group design N = 101 patients
F/M gender ratio: 52/49
Age range: 20-75 years
Astra Tech (Dentsply Implants, (Mölndal, Sweden) 67 short (6 x 4 mm)
70 longer (11-15 x 4 mm)
Sinus lift procedure using particulated bovine bone material. IF: 1 Longer and 2 Short Both treatment modalities are safe and successful rendering a high implant survival rate.
Felice et al. 2015 27 RCT N = 20 patients
F/M gender ratio: 12/8
Age range: 43-70 years
Zimmer Biomet (Florida, USA) 16 short (5-6 x 5 mm)
18 longer (10 x 6 mm)
Sinus lift procedure using granular inorganic bovine bone substitute. IF: none
MBL (one year after loading):
Short: 0.70 ± 0.19 mm
Longer: 0.87 ± 0.21 mm
Both techniques achieved excellent and similar results.
Bechara et al. 2016 31 RCT N=53 patients
F/M gender ratio: 34/19
Age range: 21-76 years
MegaGen Implant Co (Gyeongbuk, South Korea) 45 short (6 x 4-8 mm)
45 Longer (10-, 11.5-, 13-, or 15-mm x 4-8 mm)
Sinus lift procedure using a collagenated porcine particulate bone graft. IF: 2 Longer
MBL (mean):
1 year – Short: 0.14 mm
Longer: 0.21 mm
3 years – Short: 0.20 mm
Longer: 0.27 mm
Both treatment modalities showed similar results. Short implants might be preferable, because the treatment is faster and less expensive.

RCT =Randomized clinical trial ; F/M= female/male; Implant failure = IF; Marginal bone loss = MB