Osseointegration of implant surfaces in metabolic syndrome and type-2 diabetes mellitus.

This in vivo study evaluated the bone healing response around endosteal implants with varying surface topography/chemistry in a preclinical, large transitional model induced with metabolic syndrome (MS) and type-2 diabetes mellitus (T2DM). Fifteen Göttingen minipigs were randomly distributed into two groups: (i) control (normal diet, n = 5) and (ii) O/MS (cafeteria diet for obesity induction, n = 10). Following obesity induction, five minipigs from the obese/metabolic syndrome (O/MS) group were further allocated, randomly, into the third experimental group: (iii) T2DM (cafeteria diet + streptozotocin). Implants with different surface topography/chemistry: (i) dual acid-etched (DAE) and (ii) nano-hydroxyapatite coating over the DAE surface (NANO), were placed into the right ilium of the subjects and allowed to heal for 4 weeks. Histomorphometric evaluation of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO) within implant threads were performed using histomicrographs. Implants with NANO surface presented significantly higher %BIC (~26%) and %BAFO (~35%) relative to implants with DAE surface (%BIC = ~14% and %BAFO = ~28%, p < .025). Data as a function of systemic condition presented significantly higher %BIC (~28%) and %BAFO (~42%) in the control group compared with the metabolically compromised groups (O/MS: %BIC = 14.35% and %BAFO = 26.24%, p < .021; T2DM: %BIC = 17.91% and %BAFO = 26.12%, p < .021) with no significant difference between O/MS and T2DM (p > .05). Statistical evaluation considering both factors demonstrated significantly higher %BIC and %BAFO for the NANO surface relative to DAE implant, independent of systemic condition (p < .05). The gain increase of %BIC and %BAFO for the NANO compared with DAE was more pronounced in O/MS and T2DM subjects. Osseointegration parameters were significantly reduced in metabolically compromised subjects compared with healthy subjects. Nanostructured hydroxyapatite-coated surfaces improved osseointegration relative to DAE, regardless of systemic condition.

The Influence of Implant Design Features on the Bone Healing Pathway: An Experimental Study in Sheep.

This study evaluated how implant design features influence osseointegration. Two implant macrogeometries and surface treatments were evaluated: (1) progressive buttress threads with an SLActive surface (SLActive/BL), and (2) inner and outer trapezoidal threads with a nanohydroxyapatite coating over a dual acid-etched surface (Nano/U). Implants were placed in the right ilium of 12 sheep, and histologic and -metric analyses were conducted after 12 weeks. Percentages of bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) within the threads were quantified. Histologically, the SLActive/BL group showed greater and more intimate BIC than the Nano/U group. In contrast, Nano/U group depicted woven bone formation within the healing chambers, between the osteotomy wall and implant threads, and bone remodeling was evident at the outer thread tip. Significantly higher BAFO was seen in the Nano/U group than the SLActive/BL group at 12 weeks (P < .042). Different implant design features influenced the osseointegration pathway, supporting further investigations to describe the differences and clinical performance.

Synergistic Effects of Implant Macrogeometry and Surface Physicochemical Modifications on Osseointegration: An In Vivo Experimental Study in Sheep.

This study evaluates the influence of two surface physicochemical modifications on osseointegration parameters of a healing chamber implant design. We examine dental implants with internal and external trapezoidal threads that have the following surface modifications: dual acid etching (DAE) and nano-hydroxyapatite (HA) coating over DAE surface (Nano). We installed implants in the right ilium of sheep and conducted histologic/metric analyses after 3 and 12 wk in vivo. We quantified the percentage of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO) within implant threads. Histologic micrographs indicate early bone formation within the healing chambers of implants with Nano surface relative to DAE surface. Histomorphometric analysis demonstrates there to be no significant differences in %BIC between 3 and 12 wk (p = 0.298). Compared to DAE, Nano shows more bone formation in contact with implant, regardless of time (p < 0.025). We observe > %BAFO at 12 wk relative to 3 wk, which differs significantly for Nano (p < 0.038). Implant surface treatment affects the amounts of bone formation within healing chambers, with Nano significantly outperforming DAE at 12 wk (p < 0.025). Nano presents a synergistic effect with implant design, improving osseointegration parameters.

Effect of low-level laser on bone defects treated with bovine or autogenous bone grafts: in vivo study in rat calvaria.

OBJECTIVE: The purpose of this study was to histologically evaluate the effect of low-level laser (LLL) on the healing of critical size defects (CSD) in rat calvaria, filled with autogenous or inorganic bovine bone grafts. METHODS: Sixty rats were divided into 6 groups (n = 10): C (control-filled with blood clot), LLL (low-level laser-GaAlAs, λ 780 nm, 100 mW, 210 J/cm(2), Φ 0.05 cm(2); 6 J/point), AB (autogenous bone), ABL (autogenous bone + low-level laser), OB (inorganic bovine bone), and OBL (inorganic bovine bone + LLL). MATERIAL AND METHODS: The animals were killed after 30 days. Histological and histometric analyses were performed by light microscopy. Results. The groups irradiated with laser, LLL (47.67% ± 8.66%), ABL (39.15% ± 16.72%), and OBL (48.57% ± 28.22%), presented greater area of new bone formation than groups C (9.96% ± 4.50%), AB (30.98% ± 16.59%), and OB (11.36% ± 7.89%), which were not irradiated. Moreover, they were significantly better than group C (Kruskal-Wallis test followed by Dunn test, P < 0.05). CONCLUSION: The laser accelerated the healing of bone defects and the resorption of particles of the graft material.

The effect of low-level laser on bone healing in critical size defects treated with or without autogenous bone graft: an experimental study in rat calvaria.

OBJECTIVE: The objective of this study was to evaluate the effect of low-level laser (LLL) on bone healing process in surgically created critical size defects in rat calvaria treated with or without autogenous bone graft (AB). MATERIAL AND METHODS: The study was conducted on 40 male rats (Rattusnorvegicus, albinus, Wistar), weighing 250-300 g. For accomplishment of the experimental procedures, the rats were anesthetized with an intramuscular injection of xylazine (0.02 ml/kg) and ketamine hydrochloride (0.4 ml/kg). Acritical size defect with 5-mm diameter was created. The animals were divided into four groups: Group C (Control- filled with blood clot), Group LLL, Group AB (autogenous bone graft), Group AB + LLL (autogenous bone graft and LLL). The animals treated with LLL received applications of LLL at the infrared spectrum wavelength (λ = 810 nm) and energy density of 6 J/cm(2) per point, 60 s per point, adding up to five points on the entire created defect. The animals were euthanized at 30 days postoperatively. After decalcification, each specimen was longitudinally divided into two blocks, exactly along the center of the original surgical defect, processed and embedded in paraffin. Longitudinal serial sections with 6-µm thickness were made, initiating from the center of the original surgical defect. The sections were stained with hematoxylin and eosin (HE) for light microscopy analysis for histomorphometric analysis. RESULTS: Group C presented smaller quantity of new bone formation than Groups LLL (P < 0.01), AB (P < 0.01), and AB + LLL (P < 0.01). CONCLUSIONS: Utilization of LLL favored the healing process in rat calvaria. The quantity of new bone formation with use of the LLL was similar to the autogenous bone graft.