The present study aimed to evaluate the effect of dipyridamole, an indirect adenosine 2A receptors (A2AR), on the osseointegration of titanium implants in a large, translational pre-clinical model. Sixty tapered, acid-etched titanium implants, treated with four different coatings ((i) Type I Bovine Collagen (control), (ii) 10 μM dipyridamole (DIPY), (iii) 100 μM DIPY, and (iv) 1000 μM DIPY), were inserted in the vertebral bodies of 15 female sheep (weight ~65 kg). Qualitative and quantitative analysis were performed after 3, 6, and 12 weeks in vivo to assess histological features, and percentages of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO). Data was analyzed using a general linear mixed model analysis with time in vivo and coating as fixed factors. Histomorphometric analysis after 3 weeks in vivo revealed higher BIC for DIPY coated implant groups (10 μM (30.42% ± 10.62), 100 μM (36.41% ± 10.62), and 1000 μM (32.46% ± 10.62)) in comparison to the control group (17.99% ± 5.82). Further, significantly higher BAFO was observed for implants augmented with 1000 μM of DIPY (43.84% ± 9.97) compared to the control group (31.89% ± 5.46). At 6 and 12 weeks, no significant differences were observed among groups. Histological analysis evidenced similar osseointegration features and an intramembranous-type healing pattern for all groups. Qualitative observation corroborated the increased presence of woven bone formation in intimate contact with the surface of the implant and within the threads at 3 weeks with increased concentrations of DIPY. Coating the implant surface with dipyridamole yielded a favorable effect with regard to BIC and BAFO at 3 weeks in vivo. These findings suggest a positive effect of DIPY on the early stages of osseointegration.

UNASSIGNED: The ideal installation technique or implant macrogeometry for obtaining an adequate osseointegration in low-density bone tissue follows a challenge in the implantology.
UNASSIGNED: The aim of the present study was to evaluate the behavior of three osteotomy techniques and two implant macrogeometries in two low-density polyurethane blocks. The insertion torque (IT), initial stability, pullout resistance, and weight of the residual bone material deposited on the implants were assessed.
UNASSIGNED: A total of 120 implants with two different macrogeometries were used. They were divided into six groups according to the implant macrogeometry and the drilling technique performed (n = 20 implants per group). The implants were installed in polyurethane blocks with pounds per cubic foot (PCF) 10 and PCF 20 densities. The IT, initial stability, pullout resistance, and weight residual bone were measured.
UNASSIGNED: Differences were found in the values referring to the macrogeometry of the implants and the type of osteotomy performed. In all groups, the initial stability of the PCF 10 blocks was quite low. The undersized osteotomies significantly increased the values measured in all tests in the PCF 20 density blocks.
UNASSIGNED: In conclusion, even when a modified (undersized) osteotomy technique is used, implants inserted in low-quality bone (type IV) can present problems for osseointegration due their low initial stability and bone resistance. However, the modification in the implant macrogeometry (with healing chambers) presented more quantity of bone on the surface after the pullout test.

BACKGROUND: Primary implant stability is essential for osseointegration. To increase stability without changing the implant size, the thread length must be extended by reducing pitch, using a double-threaded implant, or reducing pitch/lead and lead angle to half that of a single-threaded implant.
METHODS: We tested the stabilities of these configurations using artificial bone. A 1.2-mm pitch, single-threaded implant (12S) was the control. We tested a 0.6-mm pitch/1.2-mm-lead double-threaded implant (06D) and a 0.6-mm pitch/lead single-threaded implant (06S). We compared stabilities by measuring insertion torque, removal torque, and the implant stability quotient (ISQ). Damage to bone tissue caused by the implants was evaluated using microscopy and morphometric analysis.
RESULTS: We show that 06D and 06S significantly improved stability compared with the 12S reference. The stability of 06S was significantly greater compared with that of 06D, except for ISQ. The three implants were associated with bone tissue damage characterized by debris and voids surrounding the implant/bone interface. The 06D caused the most tissue damage, followed by 06S and then 12S.
CONCLUSIONS: These findings indicate that primary stability was significantly improved by changing the implant size, extending the thread length with reduced pitch/lead, and reducing the lead angle to half that of a single-threaded implant compared with a double-threaded implant.

OBJECTIVE: The aim of the present paper is to evaluate a simplified implant site preparation technique to preserve bone bulk and enhance osseointegration using a new conical self-tapping implant in cancellous bone.
METHODS: Ten Expander® 3.8 × 10 mm implants (NoDrill®, Milano, Italy) were inserted in the right side (test group) of sheep\'s iliac crest using only the pilot drill 1.8 mm in diameter. Ten 3.8 × 10 mm Dynamix® implants (Cortex, Shlomi, Israel) were inserted in the right side (control group) of the same animals following the drilling protocol provided by the manufacturer. Histological, histomorphometric, and biomechanical analyses were performed after 2 months.
RESULTS: Implants that belonged to the test group showed a %BIC of 70.91 ± 7.95 while the control group implants had a %BIC value of 49.33 ± 10.73. The %BV was 41.83 ± 6.30 in the test group and 29.61 ± 5.05 in the control group. These differences were statistically significant. A phenomenon of osseocorticalization, characterized by more bone volume percentage around implant area than in the neighboring areas, caused by implant threads geometry, was evident in the test group.
CONCLUSIONS: This surgical protocol allows to insert an innovative fixture geometry in low-density bone using only a pilot drill. This technique demonstrated many clinical and histological advantages with respect to standard implant drilling procedures and classical implant geometry.

OBJECTIVE: The aim of this prospective clinical study was to evaluate the 3-year outcome of fixed partial prostheses supported by implants with immediate provisionalization without occlusal contacts inserted in predominantly soft bone with flap and flapless protocols.
METHODS: Forty-one patients partially rehabilitated with 72 NobelSpeedy implants (51 maxillary; 21 mandibular) were consecutively included and treated with a flapless surgical protocol (n = 20 patients; 32 implants) and flapped surgical protocol (n = 21 patients; 40 implants). Primary outcome measure was implant survival; secondary outcome measures were marginal bone resorption (comparing the bone levels at 1 and 3 years with baseline) and the incidence of biological, mechanical, and esthetic complications. Survival was computed through life tables; descriptive statistics were applied to the remaining variables of interest.
RESULTS: Eight patients with eight implants dropped out of the study. One implant failed in one patient (flapless group) giving an overall cumulative survival rate (CSR) of 98.6%. No failures were noted with the flapped protocol (CSR 100%), while for the implants placed with the flapless surgical technique, a 96.9% CSR was registered. The overall average marginal bone resorption at 3 years was 1.37 mm (SD = 0.94 mm), with 1.14 mm (SD = 0.49 mm) and 1.60 mm (SD = 1.22 mm) for the flap and flapless groups, respectively. Mechanical complications occurred in nine patients (n = 5 patients in the flapless group; n = 4 patients in the flap group). Implant infection was registered in three implants and three patients (flapless group), who exhibited inadequate oral hygiene levels.
CONCLUSIONS: Partial edentulism rehabilitation through immediate provisionalization fixed prosthesis supported by dental implants inserted through flap or flapless surgical techniques in areas of predominantly soft bone was viable at 3 years of follow-up. The limitations and risks of the \"free-hand\" method in flapless surgery should be considered when planning implant-supported fixed prosthetic reconstructions.

OBJECTIVE: The primary aim of the study was to investigate a 1-year success rate of early-loaded bone level implants with a chemically modified sand-blasted, large grit, acid-etched surface (SLActive®, Institut Straumann AG, Basel, Switzerland) in the posterior maxilla. Secondary objectives included stability of these implants and peri-implant bone level.
METHODS: Bone level® implants (Institut Straumann AG) inserted into premolar and/or molar maxillary sites were loaded after 6 weeks of healing. The implants were monitored for 1 year using the following outcome measures: implant success, primary and secondary stability, and peri-implant bone level.
RESULTS: Out of 37 implants placed in 13 patients, 36 reached sufficient stability and were early loaded, whereas one underwent a delayed loading protocol. One-year success rate of early-loaded implants was 100%. Implant stability at baseline was 71.7 ± 5. 6 to be steadily increased thereafter up to 1 year (80.3 ± 3.3), except at 2 weeks when a nonsignificant decrease was noticed (71.9 ± 3.9). Continuous and significant bone loss was observed, reaching 0.4 ± 0.1 mm in the first postoperative year.
CONCLUSIONS: Bone level implants with the SLActive surface placed into low-density bone and loaded after 6 weeks of healing can predictably achieve and maintain a successful tissue integration.

OBJECTIVE: To compare the effect of two surgical techniques, lateral condensation and bone drilling, on changes in temperature of the adjacent low-density bone during implant placement into posterior maxilla and to investigate the influence of the host factors - age, gender, region of implantation, bone density, and thickness of the cortical bone at the recipient sites.
METHODS: Local bone temperature was measured thermographically during implant placement into posterior maxilla following lateral bone condensing (test group) or bone drilling (controls). The main study outcomes were baseline bone temperature prior to implantation and maximum bone temperature recorded during implantation. Early implant success was evaluated after 6 months of healing.
RESULTS: A total of 40 implants were randomly allocated to test and control groups and placed into maxillary premolar and/or molar region of 18 participants of both genders and average age of 51.74 years. All recorded bone temperatures were below the threshold for thermal necrosis. Although both groups showed significant increase in bone temperature during implant placement procedure (P ≤ 0.0005), it was significantly higher for bone condensing compared with drilling (P ≤ 0.0005; 3.79 ± 1.54°C; 1.91 ± 0.70°C respectively). No host factor was singled out as a significant predictor of bone temperature changes, although trend of higher increase was observed in young patients, regardless of gender, during implant placement procedure into maxillary first premolar region with bone density type 3 and cortical layer thicker than 1 mm. Early implant success rate after 6 months follow-up was 100%.
CONCLUSIONS: Although both surgical techniques, bone condensing and bone drilling, can be considered safe regarding their thermal effect on the bone of posterior maxilla, bone drilling is associated with fewer local bone heating during implantation. Host factors do not affect the bone thermal changes significantly.