ABSTRACT
PURPOSE: The aim of the present animal study was to examine the impact of two implant designs that promote different insertion torque values on implant stability and evaluate, histomorphometrically, the bone healing for immediate implant placement in fresh sockets. MATERIALS AND METHODS: Twelve female sheep (35.0±5.0kg) and 48 conical Morse-taper dental implants divided into two groups (n = 24 per group): G1 group, where the implants present a design that can provide high insertion torque values; and G2 group, where the implants present a design that can provide low insertion torque values. Both had the same surface treatment, and dimensions (4.0 mm in diameter and 10 mm in length). The first two posterior teeth (both sides) were extracted carefully. Sequentially, there were osteotomies in the mesial socket of each molar tooth. The final implant position was 2 mm below the buccal bone crest level. On the right side, implants of the G1 were placed anteriorly, followed by implants of the G2; and, on the left side, it was the reverse. A digital torquemeter was used to measure the maximum final insertion torque value (f-IT). The initial implant stability quotient (ISQ) was measured immediately after the implant insertion (T0) and immediately after the euthanasia and removing the mandibles with the implants. The animals were euthanized (n=6 animals/ time) at 21 days (T1) and 35 days (T2). The t-test was used to compare statistical differences for each intragroup parameter analyzed. Pearson's correlation was used to analyze possible correlations: f-IT and BIC%, f-IT and ISQ, and ISQ and %BIC. RESULTS: Regarding the insertion torque, the G1 presented higher values than the G2, with a statistically significant difference (p<0.0001). The ISQ mean values were higher in the B-L direction than those obtained for M-D for both groups. %BIC measurements showed higher values in samples from G2 than G1 at both times and in both directions. New bone, medullary spaces, and collagen matrix had statistical differences between the groups at each evaluation time. CONCLUSION: Using implants with a modified macrogeometry plays a significant role in implant stability and the healing process of bone tissue around the implant. It is important for clinicians to carefully consider implant macrogeometry when planning dental implant surgery to achieve optimal implant stability and successful osseointegration, mainly in cases of immediate implant placement.
ABSTRACT
The aim of the present in vivo study was to analyze and compare the effects on the crestal bone healing of two different implant macrogeometries installed in fresh socket areas and in normal bone areas with different insertion torque values. Two implant macrogeometries were used in the present study, DuoCone implant (DC) and Maestro implant (MAE), forming four groups: group DCws, in which the implants were installed in healing bone (without a socket); group DCfs, in which the implants were installed in post-extraction areas (fresh sockets); group MAEws, in which the implants were installed in healing bone (without a socket); group MAEfs, in which the implants were installed in post-extraction areas (fresh sockets). After 30 and 90 days of implantations in the bilateral mandibles of 10 sheep, eighty implants were evaluated through digital X-ray images and histologic slices. The crestal bone position in relation to the implant platform shoulder was measured and compared. The measured insertion torque was 47.2 ± 4.69 Ncm for the DCws group, 43.4 ± 4.87 Ncm for the DCfs group, 29.3 ± 3.16 Ncm for the MAEws group, and 27.7 ± 4.41 Ncm for the MAEfs group. The radiographic mesio-distal and histological bucco-lingual analyses showed significantly greater vertical bone loss in the implants installed with high torque (DC groups) in comparison to the implants installed with a low torque (MAE groups) (p < 0.05), at both evaluation times. In general, low insertion torque values (Maestro implants) showed better results of MBL when compared to implants installed with higher torque values (Duo Cone implants). Moreover, our results showed that the implants installed in the sites without sockets showed a less MBL in comparison with the implants installed in sites of fresh sockets.
Subject(s)
Dental ImplantsABSTRACT
This study aims to evaluate the effects of implant macrogeometry on the early period of the osseointegration process, comparing four different implant models through biomechanical and histological analysis after implantation in rabbit tibiae. Twenty New Zealand rabbits were used, evaluated at two different times (21 and 28 days) after installation of the implant. Eighty implants with different macrogeometries were used, forming four groups (n = 20 per group): cylindrical implants Ø4.1 mm and 8 mm in length (STRc group); cylindrical-conical implants Ø4.1 mm and 8 mm in length (STRt group); tapered implants Ø4.3 mm and 8 mm in length (NOBt group); and tapered implants with healing chambers Ø4.0 mm and 8 mm in length (MAEt group). Ten samples from each group were analyzed at each proposed time. The initial implant stability quotient (ISQ) was measured by resonance frequency analysis, both at the time of installation and at the time of sacrifice. In the histological sections, the percentage of bone-implant contact (BIC%), newly formed bone, osteoid matrix, and medullary spaces were measured in the pre-determined cortical and medullary bone portion for each sample. The three tapered implant groups (STRt, NOBt, and MAEt) showed higher values for the analyzed parameters in the early osseointegration period, in comparison with the cylindrical implant group (STRc). In all parameters, the three tapered groups showed no difference (p > 0.05); however, all three tapered groups presented significant differences, when compared to the cylindrical group (p < 0.05). No correlation was detected between the parameters analyzed. Within the limitations of the present study, in all parameters analyzed, the tapered implants demonstrated greater results when compared to the cylindrical implants.
