Implant length and diameter distribution are shown in Table 1. Table 2 summarizes implant positions and prosthetic characteristics. Mean residual bone height was 6.21 ± 1.05 mm in the upper jaw and 10.73 ± 1.63 mm in the mandible, and it was significantly different between the 2 jaws (P < .05). No surgical or postsurgical complications were reported.
Results: Short implants in maxillary and mandibular rehabilitations
Implant length and diameter distribution are shown in Table 1. Table 2 summarizes implant positions and prosthetic characteristics. Mean residual bone height was 6.21 ± 1.05 mm in the upper jaw and 10.73 ± 1.63 mm in the mandible, and it was significantly different between the 2 jaws (P < .05). No surgical or postsurgical complications were reported.
Table 2. Implant positions and prosthetic characteristics; anterior implants were implants placed to substitute teeth between 1.5 to 2.5 and 3.5 to 4.5
FDI/ ADA*
Single
Splinted together
Splinted with longer one
Total
Mandible
44 (#28)
1
0
0
1
Anterior
37 (#18)
0
1
0
1
36 (#19)
2
2
0
4
35 (#20)
1
5
0
6
45 (#29)
0
3
0
3
46 (#30)
4
3
0
7
47 (#31)
2
3
0
5
Posterior
9
17
0
26
Total
10
17
0
27
Maxilla
14(#5)
1
0
0
1
23(#11)
0
0
1
1
24(#12)
1
0
0
1
Anterior
17 (#2)
0
0
2
2
16 (#3)
2
0
3
5
15 (#4)
1
0
4
5
25 (#14)
0
0
1
1
26 (#14)
1
0
4
5
27 (#15)
0
0
4
4
28 (#16)
0
0
1
1
Posterior
4
0
19
23
Total
6
0
20
26
Overall, cumulative implant survival and success rates were both 100%, and there were no prosthetic or clinical complication. Prosthesis success rate was also 100%.
One year after loading, a mean peri-implant bone loss of 0.71 ± 0.23 mm was recorded; there was no significant difference between mesial and distal measurements (P = .79). Maxillary implants had a mean bone loss of 0.69 ± 0.24 mm (Figures 1 and 2). Mandibular implants had a mean bone loss of 0.73 ± 0.23 mm (Figures 3 and 4). The difference between the 2 jaws was not statistically significant (P = .59).
Figure 1. Short implant in the posterior maxilla, placed respecting the anatomy of maxillary sinus floor.
Figure 2. One-year follow-up after definitive prosthetic rehabilitation. It can be seen that the mean marginal bone resorption was 0.78 mm and did not affect implant and prosthesis success.
Figure 3. Short implants in the posterior mandible.
Figure 4. One-year follow-up after definitive prosthetic rehabilitation
All single implants were 8.5-mm long; shorter implants were splinted together or splinted with longer implants (10 mm or 11.5 mm, which were excluded from this study). After 1 year, bone loss around single implants and splinted ones was not significantly different (P = .67). Mean bone loss was 0.73 ± 0.23 mm for single implants and 0.70 ± 0.23 mm for splinted implants. No effect of implant abutment characteristics and dimension of platform switching could be evaluated by comparing the 8.5-mm implants with shorter implants in terms of peri-implant bone loss.
The effect on bone resorption of characteristics of the opposing teeth and prosthesis was negligible. Most of the included implants had natural teeth opposing (n = 36); the rest were occluded with teeth-supported prosthesis (n = 6). implant-supported prosthesis (n = 6), or composite restorations or removable prostheses (n = 5). Neither definitive prosthesis material influenced bone loss rate.
