International Journal of Clinical Case Reports 2016, Vol.6, No.20, 1-7
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2 Discussion
It has always been considered that more the height of the implants selected, more is the success rate of the
treatment. Advantages of increased implant length include increased initial stability, long-term resistance to
bending moment forces and decreased risk of movement at the interface (Misch, 1999). In 2004, Feldman S et al
compared the 5-year survival rate of short dental implants with acid-etched surfaces to short, machined-surfaced
implants. Survival rates were 97.7% and 91.6%, respectively (Feldman et al., 2004). Bahat O placed 732 implants
in the posterior maxillae of 213 partially edentulous patients and reported a failure rate of 9.5% for 7mm implants
as compared to a mere 3.8% for all other lengths. Patients were evaluated after a 5-to 70-month follow-up period,
with a mean of 30.3 months (Bahat, 1993). Van et al (1990) found that longer and/or wider implants failed to a
lesser extent as compared to shorter, standard implants (7, 10 and 13 mm lengths) in a prospective study involving
558 implants placed in 159 partially edentulous patients, however, he also concluded that failures appeared more
in patients with poor bone quality. In a retrospective study, Scurria et al (1998) concluded that shorter implants
and implants with diameters less than 4mm have a decreased survival probability. A total of 384 implants were
placed and subsequently supported 108 prostheses. Short dental implants experienced lower survival (higher
failure rates) when compared with longer implants in another study conducted by Sheldon W et al (Sheldon et al.,
2000). A review of literature related to implant failures and length published by Goodacre et al in 2003 stated that
implant smaller than 10mm have increased failure rates (Misch, 1999). There are only a few studies which state
that even short dental implants have good success rates and that disadvantages of short dental implants could be
compensated by increasing the diameter, splinting of the implants together, decreasing crown height, decreasing
the cantilevers used, increasing the surface area and exerting minimum lateral forces (Misch, 1999). Over a 6-year
period, ten Bruggenkate CM et al placed 253 short implants (6 mm in length) in 126 patients who were then
followed-upto for 1-year to 7-years Survival of the short dental implants was comparable with the longer implants
from the same implant system. Although the clinical results of the 6mm implants were favorable, the authors
recommended that short dental implants be used in combination with longer implants, especially in less denser
bone (ten Bruggenkate et al., 1998). According to Jensen O, osseo-integrated 7mm implants were supposed to
have a better prognosis than longer implants without cortical continuity (Jensen, 1989). Friberg B et al found the
5-year survival rate to be 95.5% for a cohort of short Brånemark system implants (Friberg et al., 2000).
Davarpanah M et al found a success rate of 98.4% at a 3-year follow-up of short Osseotite implants (Davarpanah
et al., 2001). Fugazzotto PA et al in 2004 evaluated 7 to 9mm long implants placed in posterior regions of maxilla
and showed a success rate of 95.1 % up to 84-months of function (Fugazzotto et al., 2004). Hagi D et al, in their
study, concluded that dental implant surface geometry played a major role in implant success (Hagi et al., 2004).
Sintered porous surfaced implants performed well compared to threaded implants in short lengths. Finite
Elemental Analysis (FEA) has demonstrated that horizontal and vertical occlusal forces placed on implants were
distributed primarily in the crestal bone rather than along the entire implant/bone interface. Lum LB concluded
that short dental implants served as well, as longer ones, based on FEA (Lum, 1991). After osteo-integration, the
crestal bone received the majority of the occlusal load (Lum, 1991; Matsushita et al., 1990; Holmes et al., 1997).
Arlin ML evaluated 630 implants and found a success rate of 94.3% for 6mm length implants; for 8mm length
implants, success rate was 99.3%; and for 10-16mm length implants, a success rate of 96.9% was found during a
2-year follow-up period. 11 losses occurred in implants placed into type II or IV bone. The two 6.0mm length
implants lost during osseo-integration phase had been placed into type IV bone. By comparing bone augmentation
and longer implants to shorter implants’ placements, the latter was found to be simpler, less time-consuming,
cost-effective, and with low morbidity (Arlin, 2006). Romeo E et al assessed the clinical efficacy of different size
implants (8-10mm length and with 3.75, 4.1, 4.8mm width). Success rates during 14-years follow-up period for all
standard and short dental implants reached 97.9% and 97.1%, respectively. Thus, it could be concluded that
placement of varied size implants did not compromise implant success in the population studied (Romeo et al.,
2006). In the study conducted by Griffin TJ et al, 168 implants (6x8mm) with hydroxy-apatite treated surface,
were placed in 167 patients. Success rate was found to be 100% in a following-up period of 68-months (Griffin et
al., 2004). Gentile MA et al investigated the success rate of Bicon TM short implants (6x5.7 mm) compared to
