<p>The Influence of Nanostructured Hydroxyapatite Surface in the Early Stages of Osseointegration: A Multiparameter Animal Study in Low-Density Bone</p>

Abstract

Background and Objective The success rates of dental implants in low-density bone have been reported as a challenge, especially for early or immediate loading in the maxilla posterior area. Nanoscale architecture affects the roughness, surface area, surface energy of the implant and can enhance osseointegration. This study aimed to evaluate the implant-surface topography and biomechanical, histomorphometric, and histological bone responses to a new nanostructured hydroxyapatite surface placed in the iliac crest of sheep. Methods Ten female sheep (2–4 years) received 30 implants (n=10/group): HAnano ® coated (Epikut Plus ® , S.I.N. Implant System, Sao Paulo, SP, Brazil), SLActive (BLX ® , Straumann, Basel, Switzerland), and TiUnite (NobelActive ® , Nobel Biocare, Göteborg, Sweden) surfaces. Scanning electron microscopy with energy-dispersive spectroscopy evaluated the implant surface topography, the insertion torque value, and resonance frequency analysis evaluated the primary stability, bone-implant contact, and bone-area fraction occupancy were evaluated after 14 and 28 days after implant placement. Results The surface morphology was considerably comparable between the implant groups’; however, the TiUnite ® group presented a remarkable different surface. The SLActive ® and TiUnite ® groups presented an insertion torque average of 74 (±8.9) N/cm that was similar to that of HAnano ® 72 (±8.3) N/cm (p >0.05). The resonance frequency evaluated with Osstell ® /SmartPeg ® or Penguin ® /MulTipeg ® showed similar results when assessing implants from the same group. BIC and BAFO significantly increased (p<0.05) throughout the experimental periods to all groups, but BIC and BAFO values were similar among the implants at the same time point. After 4 weeks, bone-implant contact was higher than 80% of the total length analyzed. New bone occupies around 60% of analyzed area around the implants. Conclusion HAnano ® coated surface promoted comparable osseointegration as SLActive and TiUnite in the sheep model. The three tested surfaces showed comparable osseointegration at the early stages of low-density bone repair in the sheep model.

Does the Osseodensification Technique Allow for the use of a Healing Chamber with Primary Stability in Low-Density Bone? An in Vivo Study

“…Therefore, the present study was designed to verify if the OD technique could be a viable approach for standardization of the healing chamber in low-density bone when using dental implants with a biomimetic surface. The ilium of a sheep was used as the animal model because this region is considered as a low-density bone 18,27,32 , and it was already used in other histomorphometric studies involving dental implants without the need to euthanize the animals 30 . The implants used in this study have a bioactive surface with nanostructured hydroxyapatite and the only difference between the groups was the instrumentation technique of the implantation bed.…”

“…Sample size was calculated using a priori power analysis based on a previous study's results, which evaluated BIC in a same experimental animal model to estimate the effect size 27 . Considering type 1 error of 0.05 and power of 0.95, the two-tailed t-test determined a sample size of 5 implants per group/time point.…”

“…Considering type 1 error of 0.05 and power of 0.95, the two-tailed t-test determined a sample size of 5 implants per group/time point. In compliance with the reduction, re nement and replacement program 28 , the animals were also used for another study 27 . None of the animals were euthanized after the end of the present study.…”

“…A total of twenty titanium dental implants (3.5 mm of diameter and 10 mm length) with a biomimetic nHA surface (Epikut Plus®, S.I.N. Implant System, Sao Paulo, SP, Brazil), which surface morphology was already characterized in previous studies 10,27 and by Scanning Electron Microscopy (SEM) with Energydispersive X-ray spectroscopy (EDS) (Fig. 1).…”

“…Image J software (National Institutes of Health, Bethesda, MD, USA) manually determined the bone area fraction occupancy (BAFO), which was later transformed into a percentage (Fig. 3D) 27 .…”