The Influence of Surface Treatment on Osseointegration of Endosteal Implants Presenting Decompressing Vertical Chambers: An In Vivo Study in Sheep.

PURPOSE: To qualitatively and quantitatively evaluate histologic osseointegration parameters of implants designed with decompressing vertical chambers between the threads with two different surface treatments (TiO2 blasting + maleic acid vs TiO2 blasting + maleic + HCl) in a large translational animal model at 3 and 6 weeks in vivo. MATERIALS AND METHODS: Nine female sheep were used, and 72 implants with trapezoidal threads and decompressing vertical chambers of 0.6 mm in diameter and 0.2 mm in depth were placed in the ilium crest. After 3 and 6 weeks, the animals were euthanized, and biomechanical and histomophometric analyses were performed. RESULTS: Survey histologic evaluation indicated intimate contact between the bone and the implants independent of surface treatment at both times in vivo. Bone formation at both time points depicted an intramembranous-type healing pattern between the implant threads. The mean removal torque values for all groups showed a relative increase in removal torque from 3 to 6 weeks. In terms of bone area fraction occupancy analysis, significant differences were found at 6 weeks between surface treatments (P = .046), where the experimental surface yielded higher degrees of bone area fraction occupancy. CONCLUSION: Conical implants with decompressing vertical chambers between threads presented similar osseointegration parameters regarding bone-toimplant contact and torque-out test values irrespective of surface treatment. However, shifting from a minimally rough to a moderately rough surface (experimental surface with supplemental acid-etching) resulted in significantly improved bone area fraction occupancy at 6 weeks.

Effect of supplemental acid-etching on the early stages of osseointegration: A preclinical model.

PURPOSE: To evaluate the effect of two surface modifications on early osseointegration parameters of conical implants in a translational pre-clinical model. MATERIALS AND METHODS: Conical implants with progressive trapezoidal threads and healing chambers were evaluated consisting of two different surface conditions: 1) Implacil surface (IMP Sur), and 2) Implacil surface + Supplemental Acid-etching (IMP Sur + AE). Surface characterization comprised of the evaluation of roughness parameters (Sa, Sq and Sdr), surface energy and contact angle. Subsequently, implants were installed in the ilium crest of nine female sheep (weighing ~65 kg). Torque out, histological and histomorphometric analyses were conducted after 3 and 6 weeks in-vivo. The percentage of bone to implant contact (%BIC) and bone area fraction occupancy within implant threads (%BAFO) were quantified, and the results were analyzed using a general linear mixed model analysis as function of surface treatment and time in-vivo. RESULTS: Supplemental acid etching significantly increased Sa and Sq roughness parameters without compromising the surface energy or contact angle, and no significant differences with respect to Sdr. Torque-out testing yielded significantly higher values for IMP Sur + AE in comparison to the IMP Sur at 3- (62.78 ± 15 and 33.49 ± 15 N.cm, respectively) and 6-weeks (60.74 ± 15 and 39.80 ± 15 N.cm, respectively). Histological analyses depicted similar osseointegration features for both surfaces, where an intramembranous-type healing pattern was observed. At histomorphometric analyses, IMP Sur + AE implants yielded higher values of BIC in comparison to IMP Sur at 3- (40.48 ± 38 and 27.98 ± 38%, respectively) and 6-weeks (45.86 ± 38 and 34.46 ± 38%, respectively). Both groups exhibited a significant increase in %BAFO from 3 (~35%) to 6 weeks (~44%), with no significant differences between surface treatments. CONCLUSION: Supplemental acid-etching and its interplay with implant thread design, positively influenced the BIC and torque-out resistance at early stages of osseointegration.

Osteointegrative and microgeometric comparison between micro-blasted and alumina blasting/acid etching on grade II and V titanium alloys (Ti-6Al-4V).

This study evaluated the effect of alumina-blasted/acid-etched (AB/AE) or microabrasive blasting (C3-Microblasted) surface treatment on the osseointegration of commercially-pure Ti (grade II) and Ti-6Al-4V alloy (grade V) implants compared to as-machined surfaces. Surface characterization was performed by scanning electron microscopy and optical interferometry (IFM) to determine roughness parameters (Sa and Sq, n = 3 per group). One-hundred forty-four implants were placed in the radii of 12 beagle dogs, for histological (n = 72, bone-to-implant contact - BIC and bone-area-fraction occupancy -BAFO) and torque to interface failure test at 3 and 6 weeks (n = 72). SEM and IFM revealed a significant increase in surface texture for AB/AE and C3-Microblasted surfaces compared to machined surface, regardless of titanium substrate. Torque-to-interface failure test showed significant increase in values from as-machined to AB/AE and to C3-Microblasted. Considering time in vivo, alloy grade, and surface treatment, the C3-microblasted presented higher mean BIC values relative to AB/AE and machined surfaces for both alloy types. BAFO levels were significantly higher for both textured surfaces groups relative to the machined group at 3 weeks, but differences were not significant between the three surfaces for each alloy type at 6 weeks. Surface treatment resulted in roughness that improved osseointegration in Grade II and V titanium substrates.

Early Healing Evaluation of Commercially Pure Titanium and Ti-6Al-4V Presenting Similar Surface Texture: An In Vivo Study.

OBJECTIVE: This study evaluated the osseointegration of commercially pure titanium (Ti) grade-2 (G2) and Ti-6Al-4V alloy (G5) implants with the same geometry and surface treatment. MATERIALS AND METHODS: Thirty-six dental implants with a grit-blasted acid-etched surface were used (n = 18, each). Two implants, one per group, were installed in each subject, in the radius diaphysis (n = 18 beagle dogs), with interchanged fixture position (proximal-distal) between animals for a balanced number of devices per group and time in vivo (1, 3, and 6 weeks). RESULTS: Similar topographical parameters between G2 and G5 were observed for average surface roughness, root mean square, developed surface ratio, maximum height of surface, and density of summits. Removal torque was significantly higher for G5 than for G2. No differences were observed for bone-to-implant contact and bone-area-fraction occupancy. Removal torque significantly increased with time for both groups. At 1 week, new bone formation in direct contact with the implant surface and osteogenic tissue migration was observed with an increase in woven bone formation at 3 weeks followed by the onset of lamellar bone formation at 6 weeks. CONCLUSION: Although both surfaces were biocompatible and osteoconductive, increased removal torque was observed for Ti-6Al-4V compared with commercially pure Ti implants.

Bone Healing Around Dental Implants: Simplified vs Conventional Drilling Protocols at Speed of 400 rpm.

PURPOSE: This study evaluated whether simplified drilling protocols would provide comparable histologic and histomorphometric results to conventional drilling protocols at a low rotational speed. MATERIALS AND METHODS: A total of 48 alumina-blasted and acid-etched Ti-6Al-4V implants with two diameters (3.75 and 4.2 mm, n = 24 per group) were bilaterally placed in the tibiae of 12 dogs, under a low-speed protocol (400 rpm). Within the same diameter group, half of the implants were inserted after a simplified drilling procedure (pilot drill + final diameter drill), and the other half were placed using the conventional drilling procedure. After 3 and 5 weeks, the animals were euthanized, and the retrieved bone-implant samples were subjected to nondecalcified histologic sectioning. Histomorphology, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) analysis were performed. RESULTS: Histology showed that new bone was formed around implants, and inflammation or bone resorption was not evident for both groups. Histomorphometrically, when all independent variables were collapsed over drilling technique, no differences were detected for BIC and BAFO; when drilling technique was analyzed as a function of time, the conventional groups reached statistically higher BIC and BAFO at 3 weeks, but comparable values between techniques were observed at 5 weeks; 4.2-mm implants obtained statistically higher BAFO relative to 3.75-mm implants. CONCLUSION: Based on the present methodology, the conventional technique improved bone formation at 3 weeks, and narrower implants were associated with less bone formation.

Effect of Simplified One-Step Drilling Protocol on Osseointegration.

This study was designed to compare the combined effect of two different drilling techniques (conventional expansion and one-step) and four different implant geometries in a beagle dog model. The nondecalcified bone-implant samples underwent histologic/metric analysis at 2 and 6 weeks. Morphologic analysis showed similarities between different drilling technique groups and implant geometries. Histomorphometric parameters, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) were analyzed, and no statistical difference between drilling groups and/or implant geometry was found. Time was the only variable that affected BIC and BAFO, suggesting that the two protocols are equally biocompatible and osseoconductive.

Histomorphological and Histomorphometric Analyses of Grade IV Commercially Pure Titanium and Grade V Ti-6Al-4V Titanium Alloy Implant Substrates: An In Vivo Study in Dogs.

PURPOSE: To evaluate the bone response to grade IV commercially pure titanium (G4) relative to Ti-6Al-4V (G5). MATERIALS AND METHODS: Implant surface topography was characterized by optical interferometry and scanning electron microscopy (SEM). Thirty-six implants (Signo Vinces, n = 18 per group) were installed in the radius of 18 dogs. The animals were killed at 1, 3, and 6 weeks, resulting in 6 implants per group and time in vivo for bone morphology, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) evaluation. RESULTS: SEM depicted a more uniform topography of G4 than G5. Surfaces were statistically homogeneous for Sa, Sq, and Sdr. At 1 week, new bone formation was observed within the healing connective tissue in contact with the implant surface. At 3 weeks, new bone in direct contact with the implant surface was observed at all bone regions. At 6 weeks, the healing chambers filled with woven bone depicted an onset of replacement by lamellar bone. No significant effect of substrate was detected. Time presented an effect on BIC and BAFO (P < 0.001). CONCLUSION: Both titanium substrates were biocompatible and osseoconductive at the bone tissue level.