Primary Stability of a Hybrid Self‐Tapping Implant Compared to a Cylindrical Non‐Self‐Tapping Implant with Respect to Drilling Protocols in an Ex Vivo Model

Background: Modifications of implant design have been intending to improve primary stability. However, little is known about investigation of a hybrid self‐tapping implant on primary stability. Purposes: The aims of this study were to evaluate the primary stability of two hybrid self‐tapping implants compared to one cylindrical non‐self‐tapping implant, and to elucidate the relevance of drilling protocols on primary stability in an ex vivo model. Materials and Methods: Two types of hybrid self‐tapping implants (Straumann® Bone Level implant [BL], Straumann® Tapered Effect implant [TE]) and one type of cylindrical non‐self‐tapping implant (Straumann® Standard Plus implant [SP]) were investigated in the study. In porcine iliac cancellous bones, 10 implants each were inserted either using standard drilling or under‐dimensioned drilling protocol. The evaluation of implant‐bone interface stability was carried out by records of maximum insertion torque, the Periotest® (Siemens, Bensheim, Germany), the resonance frequency analysis (RFA), and the push‐out test. Results: In each drilling group, the maximum insertion torque values of BL and TE were significantly higher than SP (p = .014 and p = .047, respectively). In each group, the Periotest values of TE were significantly lower than SP (p = .036 and p = .033, respectively). The Periotest values of BL and TE were significantly lower in the group of under‐dimensioned drilling than standard drilling (p = .002 and p = .02, respectively). In the RFA, no statistical significances were found in implants between two groups and between implants in each group. In each group, the push‐out values of BL and TE were significantly higher than SP (p = .006 and p = .049, respectively). Conclusion: Hybrid self‐tapping implants could achieve a high primary stability which predicts them for use in low‐density bone. However, there is still a debate to clarify the influence of under‐dimensioned drilling on primary stability.     

Comparison of Implant Stability Before Prosthetic Loading of Two Dental Implant Systems

Dental implantology is the state of the art technique to replace missing teeth. Implant stability of implant jeopardizes its longevity and success of treatment. This study evaluates the implant stability of implant before and after 4 months of the implant placement, but before prosthetically loading it. Ten two-stage implants of Life care and Nobel Biocare dental implants were placed in 20 patients. Digital OPG was taken on the day of implant placement. After 4 months, at the time of second stage surgery, the implant stability was evaluated by the Periotest instrument. Four months after the implant placement, Periotest evaluation showed a mean of 1.9, which indicated that implants were well osseointegrated and stable. Even before prosthetically loading the two-stage implant, crestal bone loss of 0.6–0.9 mm occurred around the implant. The smooth polished collar design of the implant may have contributed to crestal bone loss.     

Effects of Implant Design and Surface on Bone Regeneration and Implant Stability: An Experimental Study in the Dog Mandible

Background: Previous experimental studies have shown a higher degree of bone‐implant contact for surface‐enlarged implants compared with machined implants. Yet, there is insufficient evidence that such implants show higher stability and an increased survival rate. Purpose: The purpose of this investigation was to study the integration and stability of grit‐blasted implants with retention elements on the implant neck, with and without marginal bone defects, compared with machined implants without retention elements. Materials and Methods: After tooth extraction of the mandibular premolars in six dogs, two grit‐blasted, partly microthreaded Astra Tech implants and one standard Branemark implant were bilaterally placed in each dog. On one side, 3 ± 3 mm large buccal defects were created, to expose three to four implant threads. The contralateral side served as control, and no defects were made. The animals were sacrificed after 4 months of healing. Implant stability was measured using resonance frequency analysis at implant installation and after 4 months of healing. Histologic and histomorpho‐metric evaluation was made after 4 months of healing. Results: Resonance frequency analysis indicated that all implants in the test and control groups were osseointegrated after 4 months, with a tendency toward higher implant stability for the Astra Tech implants. There was a statistically significant higher increase in resonance frequency for the Astra test implants compared with their corresponding controls. Histology and histomorphometry showed well‐integrated implants with varying degrees of bone repair at the defect sites. The greater bone‐implant contact for the Astra implants was statistically significant. No significant difference between the implants in amount of bone filling the threads was recorded. Conclusions: The Astra Tech implants tested showed a higher degree of bone—implant contact and higher level of bone regenerated at defect sites compared with the Brånemark implants. Resonance frequency analysis demonstrated a significantly higher increase in the Astra test implants compared with their control groups than did the Brånemark test implants versus their controls.     

Damping characteristics of bone‐to‐implant interface; A clinical study with the Periotest® device.

The Periotest® device was used to evaluate the damping characteristics of different bone‐to‐implant interfaces of Brånemark implants. Implant and abutment lengths were found to have a significant influence on Periotest value (PTV). There was no statistical difference between PTVs of implants located in the anterior and posterior areas of the same jaw at abutment connection. No differences were found between PTVs of standard and self‐tapping implants. PTVs at abutment connection were highly influenced by the bone quality. The contact with two corticals, one at each extremity of the implant, was of a greater influence in the maxillary than in the mandibular jaw, indicating a firmer anchorage between the bicortical implants and the surrounding bone. A proaressive decrease of PTVs over time was observed, significant up to 5 years of loading.     

应用共振频率评估种植体稳定性的临床研究

目的：应用共振频率分析评估牙种植体初期稳定性和预测牙种植俸骨结合．为上颌窭提升植骨同期植入种植体和种植体早期暴露的临床应用提供客观依据方法：36个病人共植入87颗牙种植体，分为3组，A组种植体早期暴露组；B组上颌宴提升植骨同期种植组；C组常规种植组即对照组在种植体植入即刻、二期暴露或修复负重前测定种植体稳定性，每一颗种植体前后测定2次测定使用的仪器是共振频率分析仪Osstell，其数值单位是ISQ.结果：三组种植体初期稳定性数值范围是5492—80．20ISQ A组初期稳定性值最高，和其他两组之间的差异存在显著性.R组和C组之间差异没有统计学意义骨结合形成后稳定性范围在57．94—79．38ISq三组种植体的后期稳定性之间差异没有统计学意义.A组和B组初期稳定性和骨结合形成后的稳定性数值前后没有差异，C组前后稳定性差异有统计学意义.结论：共振频率分析牙种植体初期稳定性和预测骨结合是一种可靠而有效的方法，同时也提示种植体早期丞露和上颌宴提升植骨同期种植术对具有适应症的病例是可行的.     

Influence of the Residual Ridge Widths and Implant Thread Designs on Implant Positioning Using Static Implant Guided Surgery

Purpose

Aggressive implant macrothread designs have been widely used. However, the effects of the aggressive thread design on the accuracy of static guided surgery, especially in a case of narrow residual ridge, have not been well-studied. The aim of this study was to evaluate the effects of two different implant macrothread designs and the residual ridge widths on the accuracy of tooth-supported static guided implant surgery.

Materials and methods

Forty implant fixtures with two different macrodesigns: a conventional thread design bone level tapered (BLT), and an aggressive thread design bone level tapered (BLX) were placed in 40 simulated polyurethane models with narrow and wide residual ridges. The placed implant positions were compared with the planned implant position and angulational deviation, as well as three-dimensional (3D) deviations at the entry and apex of the implant were measured. One-way ANOVA with Tukey's multiple comparisons (ɑ = 0.05) were used to determine level of significance between the mean and variance deviation values. 95% confidence intervals and box plots were used to demonstrate the means and ranges of precision.

Results

In terms of angulational deviation, there was no statistically significant difference in the mean deviations for both types of implants, p = 1.55 and p = 0.84 for wide and narrow ridge groups, respectively. However, the range of deviation was much larger in the narrow ridge of the BLX group compared to the BLT group. In both narrow ridge and wide ridge, the BLX group had lower mean 3D deviation values at both the entry and the apex with statistically significant differences for both entry point of the wide ridge (p = 0.027) and narrow ridge (p = 0.022) as well as at the apex of the wide ridge (p = 0.006) but not the apex of the narrow ridge (p = 0.142).

Conclusion

The aggressive larger thread design of dental implants may influence the accuracy of implant placement more than the ridge dimension.     

种植体设计对即刻种植与即刻负荷成功的影响

即刻种植和即刻负荷成功的关键是种植体的初期稳定性,除了宿主因素和医源因素外,影响初期稳定性的关键是种植体的设计。本文就目前种植体的尺寸、外形、表面处理对种植体即刻种植和即刻负荷成功影响的研究进展作一综述。     

Development of a New Implant Primary Stability Parameter: Insertion Torque Revisited

Purpose: The aims of the study are to introduce a new parameter to measure primary stability and to evaluate the possible correlations between this parameter and bone density, initial bone‐to‐implant contact (IBIC), Resonance Frequency Analysis (RFA), and peak insertion torque (IT). Material and Methods: The study was performed on three different types of fresh humid bovine bone: type I, type II, and type III. A total of 90 XiVE implants (30 per bone type) were used; implant insertion was performed with a calibrated maximum torque of 70 Ncm at predetermined 30 rpm. The IT data were recorded and exported as a curve; using a trapezoidal integration technique, the area underlying the curve was calculated: this area represents the variable torque work (VTW). Furthermore, peak IT and RFA were recorded; finally IBIC was calculated from histological specimens. Results: Spearman correlation analysis of the entire sample reveals that VTW presents a significant (p < .01) positive correlation with bone density; a significant (p < .05) positive correlation with IBIC, and a significant (p < .01) positive correlation with all the other primary stability parameters. Spearman correlation analysis of the three different groups show that VTW presents a significant positive correlation with IT in all three types of bone; on the other hand, VTW shows a negative not significant correlation with RFA in bone I, a positive significant correlation in bone II, and a positive not significant correlation in bone III. Furthermore, VTW shows a negative significant correlation with IBIC in bone I and a positive significant correlation in bone II and III. Conclusions: Within the limitations of an in vitro study, the VTW seems to be a promising parameter to measure implant primary stability.     

自攻型微螺钉种植体支抗稳定性的临床研究

目的:研究自攻型微螺钉种植体加载正畸负荷后的稳定性。方法:本研究包括了15例成年患者,以植入上颌颧突的自攻型微螺钉作为前牙内收的颌内支抗。微螺钉植入2周后施力。加力前及加力后9个月分别拍摄X线头颅定位片,将头影测量片进行重叠,测量微螺钉的移位变化。结果:15例中6例患者的微螺钉伸出并向前移位(-0.5～1.5mm)。微螺钉头部平均向前移位0.4mm,有统计学意义(P<0.05)。结论:自攻型微螺钉种植体是一种稳定的支抗装置,但是在承载正畸负荷的过程中,并不保持绝对的稳定,部分微螺钉在正畸力作用下有移位。为了防止因种植体移位伤及临近的重要组织结构,建议自攻型微螺钉应植入在没有主要神经、血管通过的非齿槽骨区,或植入在齿槽间隔区,但种植体与牙根之间应留出2mm的安全距离。     

The Effects of Cortical Bone Thickness and Trabecular Bone Strength on Noninvasive Measures of the Implant Primary Stability Using Synthetic Bone Models

Purpose: This study investigated how the primary stability of a dental implant as measured by the insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ) is affected by varying thicknesses of cortical bone and strengths of trabecular bone using synthetic bone models. Materials and Methods: Four synthetic cortical shells (with thicknesses of 0, 1, 2, and 3 mm) were attached to four cellular rigid polyurethane foams (with elastic moduli of 137, 47.5, 23, and 12.4 MPa) and one open‐cell rigid polyurethane foam which mimic the osteoporotic bone (with an elastic modulus 6.5 MPa), to represent the jawbones with various cortical bone thicknesses and strengths of trabecular bone. A total of 60 bone specimens accompanied with implants was examined by a torque meter, Osstell resonance frequency analyzer, and Periotest electronic device. All data were statistically analyzed by two‐way analysis of variance. In addition, second‐order nonlinear regression was utilized to assess the correlations of the primary implant stability with the four cortex thicknesses and five strengths of trabecular bone. Results: ITV, ISQ, and PTV differed significantly (p < .05) and were strongly correlated with the thickness of cortical bone (R² > 0.9) and the elastic modulus of trabecular bone (R² = 0.74–0.99). Conclusions: The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the strength of trabecular bone; however, these factors are mostly nonlinearly correlated with ITV, PTV, and ISQ. Using ITV and PTV seems more suitable for identifying the primary implant stability in osteoporotic bone with a thin cortex.