Evaluation of Implants with Different Macrostructures in Type I Bone—Pre-Clinical Study in Rabbits

Abstract

The objective of this study was to assess the primary stability and the osseointegration process in implants with different macrostructures (Cylindrical vs. Hybrid Conical) in rabbit tibiae. Twenty-four (24) rabbits were used, divided into 3 experimental periods (2, 4 and 8 weeks) with 8 animals each. Each animal bilaterally received 2 implants from each group in the tibial metaphysis: Cylindrical Implant (CI) and Hybrid Conical Implant (HCI). All implants were assessed for insertion torque. After the experimental periods, one of the implants in each group was submitted to the removal counter-torque test and descriptive histological analysis while the other implant was used for microtomographic and histometric analysis (%Bone-Implant Contact). HCI implants showed higher insertion torque (32.93 ± 10.61 Ncm vs. 27.99 ± 7.80 Ncm) and higher % of bone-implant contact in the 8-week period (79.08 ± 11.31% vs. 59.72 ± 11.29%) than CI implants. However, CI implants showed higher values of removal counter-torque than HCI implants in the 8-week period (91.05 ± 9.32 Ncm vs. 68.62 ± 13.70 Ncm). There were no differences between groups regarding microtomographic data. It can be concluded that HCI implants showed greater insertion torque and bone-implant contact in relation to CI implants in the period of 8 weeks when installed in cortical bone of rabbits.

Influence of Implant Design and Under-Preparation of the Implant Site on Implant Primary Stability. An In Vitro Study

“…The implant industry has shown an increased interest in the development of new implant designs, mostly addressed to increase the IPS for the so-called immediate loading treatments [30,31]. Mainly tapered implants or its modifications have been shown to provide higher IPS when compared to cylindrical or non-tapered designs [21,32,33]. When considering immediate loading in which IPS is a determinant factor, there seems to be a general agreement that tapered or conical implants will provide better results [10].…”

Effect of different thread configurations on hydrophilic implant stability. A split-mouth RCT

“…The success of dental implants is directly influenced by the level of primary stability after implant placement 15 , and the implant macrostructure plays an important role in achieving primary stability 7 , 12 . The shape of implants and the thread configurations influence this parameter, as demonstrated in previous studies in which tapered implants presented greater stability than cylindrical implants 8 , 12 , 15 .…”

“…The shape of implants and the thread configurations influence this parameter, as demonstrated in previous studies in which tapered implants presented greater stability than cylindrical implants 8 , 12 , 15 . The implants used in the current study have a hybrid macrostructure in which there is an association of a cylindrical shape in the coronal portion and a tapered shape in the lower portion with a double-threaded design, and this type of implant macrostructure has also been shown to present superior stability to cylindrical implants with single-threaded design 7 , 16 . Taking into account the data obtained on primary stability in this study, both implants presented adequate values of insertion torque, which demonstrates the effectiveness of this type of implant format in obtaining locking even in low-density bone such as in the posterior region of the jaw.…”

“…The implant sites were randomly allocated to receive one of the two implant types. The implants in the CTP group were cylindrical in the middle and coronal portion and tapered in the apical portion with perforating threads (Titamax EX®, Cone Morse, Neodent, Curitiba, Brazil) and the implants in the CTH group were cylindrical in the coronal portion and conical in the apical and middle portion with hybrid threads configuration (perforating and condensing threads) (Helix®, Grand Morse, Neodent, Curitiba, Brazil) ( Figure 1 ) 7 . The implants had a diameter of 3.75 mm and a length of 9 mm (CTP) or 10 mm (CTH), presented morse taper connection, the same hydrophilic surface (Acqua, Neodent, Curitiba, Brazil), and were installed 2mm subcrestally.…”

“…One controllable factor linked to success in osseointegration is the achievement of good primary stability, which makes secondary stability a more predictable event (2,3). Structural modifications in dental implants have been proposed to optimize the osseointegration process, and these modifications can be performed in the macrostructure or microstructure of the implants (3)(4)(5)(6)(7). Changes in the macrostructure more directly affect primary stability and the decision to establish immediate load application (3,6,8), while microstructural modifications are related to the acceleration of the conversion from primary to secondary stability due to biological stimuli in the osseointegration process (5,(9)(10)(11).…”