Stability of smooth and rough mini-implants: clinical and biomechanical evaluation - an in vivostudy

Abstract

Objective: To compare in vivo orthodontic mini-implants (MI) of smooth (machined) and rough (acid etched) surfaces, assessing primary and secondary stability. Methods: Thirty-six (36) MI were inserted in the mandibles of six (6) dogs. Each animal received six (6) MI. In the right hemiarch, three (3) MI without surface treatment (smooth) were inserted, whereas in the left hemiarch, another three (3) MI with acid etched surfaces (rough) were inserted. The two distal MI in each hemiarch received an immediate load of 1.0 N for 16 weeks, whereas the MI in the mesial extremity was not subject to loading. Stability was measured by insertion and removal torque, initial and final mobility and by inter mini-implant distance. Results: There was no statistical behavioral difference between smooth and rough MI. High insertion torque and reduced initial mobility were observed in all groups, as well as a reduction in removal torques in comparison with insertion torque. Rough MI presented higher removal torque and lower final mobility in comparison to smooth MI. MI did not remain static, with displacement of rough MI being smaller in comparison with smooth MI, but with no statistical difference. Conclusions: MI primary stability was greater than stability measured at removal. There was no difference in stability between smooth and rough MI when assessing mobility, displacement and insertion as well as removal torques.

Effect of surface treatment on the mechanical stability of orthodontic miniscrews:

“…It further enhances fibrin attachment, prevents detachment of fibrin during wound healing, and facilitates bone matrix formation in direct contact with the MSs, thereby improving biocompatibility and stability. [29][30][31][32] In the present review, three studies 8,10,18 with SLA surface-treated MSs were used to assess ITV variation, and the forest plot of ITV showed SMD of -6.19 (95% CI ¼ -13.63-1.25, I 2 ¼ 98%, P ¼ .10), with no statistically significant difference. Wide variation in torque values could be due to variation in length and diameter of MSs, initial pilot hole size, placement method (monocortical vs bicortical placement, wet vs dry placement), and thickness of cortical bone where the MS was placed.…”

“…2 The present systematic review with meta-analysis was conducted to compare the mechanical stability of surface-treated MSs with conventional untreated machine surface MSs. A total of 14 studies were used in the qualitative synthesis 8,10,12-23 and seven studies 8,10,13,14,18,19,22 in quantitative synthesis of data.…”

“…32 Surface treatment enhances the roughness and hydrophilicity of MSs, thereby increasing retention and RTVs. In the present review, seven studies 8,10,13,14,18,19,22 were included that assessed the variation in RTV of SLA surface-treated versus conventional machined surface MSs, and the result showed significantly higher RTV for surface-treated MSs with SMD of 2.61 (P , .001). RTV is the measure of bone-implant contact, and increased RTV indicates better osseointegration, with improved secondary stability.…”

“…13 Previously, authors have studied various modalities of surface treatment of MSs, such as surface acid etching, sandblasting, plasma ion implantation, anodic oxidation, alkali treatment, and so on. 8,[10][11][12][13][14][15][16][17][18][19][20][21][22][23] The present systematic review with meta-analysis was conducted to provide collective quantitative evidence about the effect of these surface treatments on the mechanical stability of MSs.…”

Influence of orthodontic mini-screw surface modifications on implant topography and osseointegration: an in- vivo study.

“…To produce the reduced-size mini-screws with high fracture strength, titanium alloy (Ti 6 Al 4 V) -rather than commercially-pure titanium (cpTi)-is used. However, this alloy is characterized by lower osseointegration potential and higher corrosion susceptibility in-vivo, which can reduce the implant stability and its long-term success 5,8 . According to Albrektsson et al 9 , surface topography and chemistry of dental implants, have an essential impact on their osseointegration.…”