A comparative study on the initial stability of different implants placed above the bone level using resonance frequency analysis

PURPOSE: This study evaluated the initial stability of different implants placed above the bone level in different types of bone. MATERIALS AND METHODS: As described by Lekholm and Zarb, cortical layers of bovine bone specimens were trimmed to a thickness of 2 mm, 1 mm or totally removed to reproduce bone types II, III, and IV respectively. Three Implant system (Branemark System(R) Mk III TiUnite(TM), Straumann Standard Implant SLA(R), and Astra Tech Microthread(TM)-OsseoSpeed(TM)) were tested. Control group implants were placed in level with the bone, while test group implants were placed 1, 2, 3, and 4 mm above the bone level. Initial stability was evaluated by resonance frequency analysis. Data was statistically analyzed by one-way analysis of variance in confidence level of 95%. The effective implant length and the Implant Stability Quotient (ISQ) were compared using simple linear regression analysis. RESULTS: In the control group, there was a significant difference in the ISQ values of the 3 implants in bone types III and IV (P<.05). The ISQ values of each implant decreased with increased effective implant length in all types of bone. In type II bone, the decrease in ISQ value per 1-mm increase in effective implant length of the Branemark and Astra implants was less than that of the Straumann implant. In bone types III and IV, this value in the Astra implant was less than that in the other 2 implants. CONCLUSION: The initial stability was much affected by the implant design in bone types III, IV and the implant design such as the short pitch interval was beneficial to the initial stability of implants placed above the bone level.

Influence of implant diameter and length changes on initial stability / 대한치과보철학회지

STATEMENT OF PROBLEM: Adequate bone quality and quantity were important to achieve initial stability and to prevent early failures. However there were few published data available regarding the actual effect of dimensional change in implant geometry on initial stability. PURPOSE: The purpose of the current study was to investigate the influence of diameter and length changes on initial stability of implants. MATERIAL AND METHODS: Four types of dummy bone (D1, D2, D3 and D4) consisted of cortical and cancellous layers with different thickness were simulated. Implants which had similar surface area to each other (3.5 x 13.0-mm, 4.0 x 11.5-mm, 4.5 x 10.0-mm, 5.0 x 8.5-mm) were inserted in dummy bones. Implant stability as a function of peak insertion torque and resonance frequency values were recorded for each implant. RESULTS: 1. Bone quality was a major influential factor to achieve initial stability (P .05), however insertion torques were increased with wider and shorter implants (P < .05). 3. In D4 dummy bone, implant stability quotient values and insertion torques were decreased with wider and shorter implants (P <. 05). CONCLUSION: From a point of view of initial stability, it is suggested that use of wide and short implant may be helpful in avoiding bone augmentation procedures in area of adequate bone quality.

The Influence of the Initial Stability After Dental Implant Installation on the Osseointegration

Bone response of three different surface implants : Histomorphometric, perio test value and resonance frequency analysis in beagle dogs / 대한치과보철학회지

STATEMENT OF PROBLEM: The intial stability for osseointegration of implant has been an interesting factor. Especially, in the case of poor bone quality or immediately loaded implant, various strategies have been developed focusing on the surface of materials to improve implant fixation to bone. The microscopic properties of implant surfaces play a major role in the osseous healing of dental implants. PURPOSE: The aims of this study are to perform a histologic and histomorphometric comparison of the healing characteristics of three different surfaces and the comparison of resonance frequency analysis (RFA) values measured by Osstell(TM) and perio-test values (PTV) measured by Periotest. MATERIAL AND METHODS: A total of 24 screw titanium implants (Dentium Co., Seoul, Korea) with 6mm in length and 3.4mm in diameter, were placed in the mandible of 4 beagle dogs. Implants were divided into three groups following the surface treatment methods: Group I is machined(control group). Group II is anodically oxidized. Group III is coated 500nm in thickness with hydroxyapatite(HA) by ion beam assisted deposition(IBAD) on the anodized oxidization. Bone blocks from 2 dogs were caught after 3 weeks of covered healing and another blocks from 2 dogs after 6 weeks. RFA values and PTV were measured right after insertion and at 3 and 6weeks. Histomorphometric analysis was made with Kappa Image Base System to calculate bone-to-implant contact (BIC) and bone area inside the threads. Pearson's correlation analyses were performed to evaluate the correlation between RFA and PTV, BIC and bone area ratio of three different surfaces at 3 and 6 weeks. RESULTS: 1) In all surface treatment methods, the RFA values decreased and the PTV values increased until 6 weeks in comparison to initial values. 2) At 3 weeks, no significant difference was found from bone-to-implant contact ratio and bone area ratio of three different surface treatment methods(P>0.05). However, at 6 weeks, different surface treatment methods showed significantly different bone-toimplant contact ratio and bone area ratio(P<0.05). 3) In the implants with the IBAD on the anodic oxidization, significant difference was found between the 3 weeks and the 6 weeks bone area ratio(P<0.05). 4) Correlation was found between the RFA values and the bone area ratio at 3 and 6 weeks with significant difference(P<0.05). CONCLUSIONS: These results indicate that the implants with the IBAD on the anodic oxidization may have a high influence on the initial stability of implant.

The initial stability of CF/PEEK femoral stem after total hip replacement / 中华创伤骨科杂志

Objective To explore the initial stability of a carbon fiber reinforced polyetheretherketone composite (CF/PEEK) stem in human femurs after total hip replacement. Methods 8 pairs of human cadaveric femurs were used to test the CF/PEEK prosthesis versus a conventional cementless stem of cobalt-chrome molybdemum alloy(CoCrMo). The bone-femoral prosthesis interface motion was measured in vitro using displacement transducers. Combined axial and torsional loads and simulated single-leg stance loading were applied. Subsidence, rotation and interface motion were measured with load cycles up to 1 000 N. Results The extent of the micro-motion in the proximal femoral region was larger than that in the distal femoral region. The CF/PEEK composite prosthesis showed less dynamic micro-motion in the proximal region compared with the CoCrMo alloy prosthesis stem, with the average difference being 42%. The extent of the distal micro-motion in the 2 groups was small but the difference was significant (P

CONFOCAL LASER SCANNING MICROSCOPY STUDY ON INTERFACE BONE AND TITANIUM IMPLANT COATED BY CHITOSAN

The purpose of present study was to observe the radiographic finding and histologic response by Confocal Laser Scanning Microscopy(CLSM) on interface of the bone and titanium implant coated by chitosan. The tissue of rabbit tibiae to the surgical placement titanium implant coated by chitosan was examined at 3, 9 and 24 days postoperatively. The radiographic finding showed that surrounding bone density of implants was not significantly different compare with the bone on 3 and 9 days group. A large amount new bone was formed on 24 days group, the reason was osteconduction activity by chitosan. The CLSM analysis show that the surface coating by chitosan filled the gap between bone and implant on 3 days group and filled by mew born on 9 days group. On 24 days group, the bone and titanium surface was filled by lamella bone. This results indicated that this enhanced the initial stability of implant significantly and chitosan induced osseointegration around implant. CLSM allows the non-destrutive histo-tomography of bone biopsy as well as clinical practice. We conclude that CLSM allowed a good comprehension of the nature of bone-implant contact, avoiding artifacts due to the thickness of the specimen.