Precision of fit and retention force of cast non-precious-crowns on standard titanium implant-abutment with different design and height

OBJECTIVE The cost-effectiveness of cast nonprecious frameworks has increased their prevalence in cemented implant crowns. The purpose of this study was to assess the effect of the design and height of the retentive component of a standard titanium implant abutment on the fit, possible horizontal rotation and retention forces of cast nonprecious alloy crowns prior to cementation. MATERIALS AND METHODS Two abutment designs were examined: Type A with a 6° taper and 8 antirotation planes (Straumann Tissue-Level RN) and Type B with a 7.5° taper and 1 antirotation plane (SICace implant). Both types were analyzed using 60 crowns: 20 with a full abutment height (6 mm), 20 with a medium abutment height (4 mm), and 20 with a minimal (2.5 mm) abutment height. The marginal and internal fit and the degree of possible rotation were evaluated by using polyvinylsiloxane impressions under a light microscope (magnification of ×50). To measure the retention force, a custom force-measuring device was employed. STATISTICAL ANALYSIS one-sided Wilcoxon rank-sum tests with Bonferroni-Holm corrections, Fisher's exact tests, and Spearman's rank correlation coefficient. RESULTS Type A exhibited increased marginal gaps (primary end-point: 55 ± 20 μm vs. 138 ± 59 μm, P < 0.001) but less rotation (P < 0.001) than Type B. The internal fit was also better for Type A than for Type B (P < 0.001). The retention force of Type A (2.49 ± 3.2 N) was higher (P = 0.019) than that of Type B (1.27 ± 0.84 N). Reduction in abutment height did not affect the variables observed. CONCLUSION Less-tapered abutments with more antirotation planes provide an increase in the retention force, which confines the horizontal rotation but widens the marginal gaps of the crowns. Thus, casting of nonprecious crowns with Type A abutments may result in clinically unfavorable marginal gaps.

Complications with computer-aided designed/computer-assisted manufactured titanium and soldered gold bars for mandibular implant-overdentures: short-term observations

BACKGROUND Implant-overdentures supported by rigid bars provide stability in the edentulous atrophic mandible. However, fractures of solder joints and matrices, and loosening of screws and matrices were observed with soldered gold bars (G-bars). Computer-aided designed/computer-assisted manufactured (CAD/CAM) titanium bars (Ti-bars) may reduce technical complications due to enhanced material quality. PURPOSE To compare prosthetic-technical maintenance service of mandibular implant-overdentures supported by CAD/CAM Ti-bar and soldered G-bar. MATERIALS AND METHODS Edentulous patients were consecutively admitted for implant-prosthodontic treatment with a maxillary complete denture and a mandibular implant-overdenture connected to a rigid G-bar or Ti-bar. Maintenance service and problems with the implant-retention device complex and the prosthesis were recorded during minimally 3-4 years. Annual peri-implant crestal bone level changes (ΔBIC) were radiographically assessed. RESULTS Data of 213 edentulous patients (mean age 68 ± 10 years), who had received a total of 477 tapered implants, were available. Ti-bar and G-bar comprised 101 and 112 patients with 231 and 246 implants, respectively. Ti-bar mostly exhibited distal bar extensions (96%) compared to 34% of G-bar (p < .001). Fracture rate of bars extensions (4.7% vs 14.8%, p < .001) and matrices (1% vs 13%, p < .001) was lower for Ti-bar. Matrices activation was required 2.4× less often in Ti-bar. ΔBIC remained stable for both groups. CONCLUSIONS Implant overdentures supported by soldered gold bars or milled CAD/CAM Ti-bars are a successful treatment modality but require regular maintenance service. These short-term observations support the hypothesis that CAD/CAM Ti-bars reduce technical complications. Fracture location indicated that the titanium thickness around the screw-access hole should be increased.

In Vivo Evaluation of the Phenox CRC Mechanical Thrombectomy Device in a Swine Model of Acute Vessel Occlusion

Mechanical thrombectomy in ischemic stroke is of increasing interest as it is a promising strategy for fast and efficient recanalization. Several thrombectomy devices have been introduced to the armentarium of mechanical thrombectomy. Currently, new devices are under development and are continuously added to the neurointerventional tool box. Each device advocated so far has a different design and mechanical properties in terms of thrombus-device interaction. Therefore, a systematic evaluation under standardized conditions in vivo of these new devices is needed. The purpose of this study was to evaluate the efficiency, thrombus-device interaction, and potential complications of the novel Phenox CRC for distal mechanical thrombectomy in vivo. The device was evaluated in an established animal model in the swine. Recanalization rate, thromboembolic events, vasospasm, and complications were assessed. Radiopaque thrombi (2 cm length) were used for the visualization of thrombus-device interaction during retrieval. The Phenox CRC (4 mm diameter) was assessed in 15 vessel occlusions. For every occlusion a maximum of 3 retrieval attempts were performed. Complete recanalization (TICI 3/TIMI 3) was achieved in 86.7% of vessel occlusions. In 66.7% (10/15), the first retrieval attempt was successful, and in 20% (3/15), the second attempt led to complete recanalization of the parent artery. In 2 cases (13.3%) thrombus retrieval was not successful (TICI 0/TIMI 0). In 1 case (6.7%) a minor embolic event occurred in a small side branch. No distal thromboembolic event was observed during the study. Thrombus-device interaction illustrated the entrapment of the thrombus by the microfilaments and the proximal cage of the device. No significant thrombus compression was observed. No vessel perforation, dissection, or fracture of the device occurred. In this small animal study, the Phenox CRC was a safe and effective device for mechanical thrombectomy. The unique design with a combination of microfilaments and proximal cage reduces thrombus compression with a consequently high recanalization and low complication rate.

In vivo performance of a laser fluorescence device for the approximal detection of caries in permanent molars

OBJECTIVES: The aim of this randomised clinical trial was to investigate if a laser fluorescence device is able to discriminate between sound and carious approximal sites and between enamel and dentinal lesions, as well as to find appropriate cut-off values. METHODS: One hundred and seventeen sound or uncavitated carious sites in permanent molars were visually and radiographically examined, then either opened or not, after which their laser fluorescence was measured. Forty-three lesions were opened, the caries removed and the clinically identified caries depths were registered in addition to the radiographical scoring. Seventy-four sites were radiographically deemed sound or had enamel caries and were not opened. Here, the radiographical scorings were registered. RESULTS: Taking the radiographic scoring as gold standard for all investigated approximal sites, sound sites (D(0), n=40) showed significantly lower laser fluorescence measurements than carious sites (D(1-4), n=77) (Mann-Whitney test, P<0.025) suggesting a cut-off at 7 (sensitivity=0.68, specificity=0.7). Comparing measurements of D(0-2) (n=74) and D(3,4) (n=43), the results were also different by a statistically significant amount (P<0.025) and the cut-off calculated to be 16 (sensitivity=0.6, specificity=0.84). A fair positive correlation between laser fluorescence values and radiographical scoring was found (rho=+0.47, P<0.01). Analysing the 43 opened lesions with their clinically found lesion depths as gold standard, there was a fair positive correlation to the laser fluorescence values (rho=+0.34, P=0.03) and a moderately strong correlation to the radiographic scoring (rho=+0.67, P<0.01). CONCLUSION: The device may be an adjunct tool in the approximal detection of caries along with established procedures.

Early loading at 21 days of non-submerged titanium implants with a chemically modified sandblasted and acid-etched surface: 3-year results of a prospective study in the posterior mandible

BACKGROUND: This study evaluates 3-year success rates of titanium screw-type implants with a chemically modified sandblasted and acid-etched surface (mod SLA), which were functionally loaded after 3 weeks of healing. METHODS: A total of 56 implants, inserted in the posterior mandibles of 39 partially edentulous patients, underwent undisturbed healing for 3 weeks. At day 21, the implants were fully loaded with provisional crowns. Definitive metal ceramic restorations were fabricated after 6 months of healing. Clinical measurements regarding soft tissue parameters and radiographs were obtained at different time points up to 36 months after implant placement. The soft tissue and radiographic parameters for the mod SLA implants after 3 years in function were compared to a historic control group of implants with an SLA surface using an early loading protocol after 6 weeks. RESULTS: None of the implants failed to integrate. However, two implants were considered "spinners" at day 21 and were left unloaded for an extended period. Therefore, 96.4% of the inserted implants were loaded according to the protocol tested. All 56 implants, including the "spinners," showed favorable clinical and radiographic findings at the 3-year follow-up examination. All 56 implants were considered successfully integrated, resulting in a 3-year survival and success rate of 100%. Dental implants with a mod SLA surface demonstrated statistically significant differences for probing depths and clinical attachment level values compared to the historic control group, with the mod SLA surface implants having overall lower probing depths and clinical attachment level scores. CONCLUSION: This prospective study using an early loading protocol demonstrates that titanium implants with the mod SLA surface can achieve and maintain successful tissue integration over a period of 3 years.

Early loading after 21 days of healing of nonsubmerged titanium implants with a chemically modified sandblasted and acid-etched surface: two-year results of a prospective two-center study

PURPOSE: The aim of this two-center study was to evaluate screw-type titanium implants with a chemically modified, sandblasted and acid-etched surface when placed in the posterior maxilla or mandible, and loaded 21 days after placement. MATERIAL AND METHODS: All 56 patients met strict inclusion criteria and provided informed consent. Each patient displayed either a single-tooth gap, an extended edentulous space, or a distal extension situation in the posterior mandible or maxilla. Eighty-nine dental implants (SLActive, Institut Straumann AG, Basel, Switzerland) were inserted according to an established nonsubmerged protocol and underwent undisturbed healing for a period of 21 days. Where appropriate, the implants were loaded after 21 days of healing with provisional restorations in full occlusion. Definitive metal ceramic restorations were fabricated and positioned on each implant after 6 months of healing. Clinical measurements regarding soft tissue parameters and radiographs were obtained at different time points up to 24 months after implant placement. RESULTS: Of the 89 inserted implants, two (2.2%) implants failed to integrate and were removed during healing, and two (2.2%) additional implants required a prolonged healing time. A total of 85 (95.6%) implants were therefore loaded without incident after 21 days of healing. No additional implant was lost throughout the study period, whereas one implant was lost to follow-up and therefore left unaccounted for further analysis. The remaining 86 implants all exhibited favorable radiographic and clinical findings. Based on strict success criteria, these implants were considered successfully integrated 2 years after insertion, resulting in a 2-year success rate of 97.7%. CONCLUSION: The results of this prospective two-center study demonstrate that titanium implants with a modified SLA surface can predictably achieve successful tissue integration when loaded in full occlusion 21 days after placement. Integration could be maintained without incident for at least 2 years of follow-up.

Treatment of peri-implantitis using an Er:YAG laser or an air-abrasive device: a randomized clinical trial

Non-surgical peri-implantitis therapies appear to be ineffective. Limited data suggest that ER:YAG laser therapy improves clinical conditions. The present study aimed at comparing the treatment effects between air-abrasive (AM) and Er:YAG laser (LM) mono-therapy in cases with severe peri-implantitis.

Autotransfusion system or integrated automatic suction device in minimized extracorporeal circulation: influence on coagulation and inflammatory response

To measure surrogate markers of coagulation activation as well as of the systemic inflammatory response in patients undergoing primary elective coronary artery bypass grafting (CABG) using either the so-called Smart suction device or a continuous autotransfusion system (C.A.T.S.®).

Design of a semi-implantable hearing device for direct acoustic cochlear stimulation

A new hearing therapy based on direct acoustic cochlear stimulation was developed for the treatment of severe to profound mixed hearing loss. The device efficacy was validated in an initial clinical trial with four patients. This semi-implantable investigational device consists of an externally worn audio processor, a percutaneous connector, and an implantable microactuator. The actuator is placed in the mastoid bone, right behind the external auditory canal. It generates vibrations that are directly coupled to the inner ear fluids and that, therefore, bypass the external and the middle ear. The system is able to provide an equivalent sound pressure level of 125 dB over the frequency range between 125 and 8000 Hz. The hermetically sealed actuator is designed to provide maximal output power by keeping its dimensions small enough to enable implantation. A network model is used to simulate the dynamic characteristics of the actuator to adjust its transfer function to the characteristics of the middle ear. The geometry of the different actuator components is optimized using finite-element modeling.

Danger assessment of a spring-gun device (muzzleloader) loaded only with black powder

We report a case involving a spring-gun device (muzzleloader) loaded solely with gunpowder, installed next to shoes to prevent the neighbors' puppy from removing them. The booby trap was triggered by the 15-year-old dog-owners son when he tried to put the shoes out of the reach of the puppy. The boy suffered second degree superficial burns located mainly at the dorsal side of the right hand and fingers. To estimate the danger of the used weapon, several tests were undertaken on soap blocks from different distances and with different loads of black powder. The particle density per mm and the depth of black powder tattooing in the soap was compared with the boy's injuries, and found conclusive with the gun-owners statement regarding the loading of the weapon. Furthermore, our experiments indicated that the gunpowder load involved was not able to inflict permanent damage, not even to the eyes, at the here estimated firing distance.

Pooled analysis of trials comparing titanium-nitride-oxide-coated stents with paclitaxel-eluting stents in patients undergoing coronary stenting

We performed a pooled analysis of three trials comparing titanium-nitride-oxide-coated bioactive stents (BAS) with paclitaxel-eluting stents (PES) in 1,774 patients. All patients were followed for 12 months. The primary outcomes of interest were recurrent myocardial infarction (MI), death and target lesion revascularization (TLR). Secondary endpoints were stent thrombosis (ST) and major adverse cardiac events (MACE) including MI, death and TLR. There were 922 patients in the BAS group and 852 in the PES group. BAS significantly reduced the risk of recurrent MI (2.7% vs. 5.6%; risk ratio 0.50, 95% CI 0.31-0.81; p = 0.004) and MACE (8.9% vs. 12.6%; risk ratio 0.71, 95% CI 0.54-0.94; p = 0.02) during the 12 months of follow up. In contrast, the differences between BAS and PES were not statistically significant with respect to TLR (risk ratio 0.98, 95% CI 0.68-1.41), death (risk ratio 0.96, 95% CI 0.61-1.51) and definite ST (risk ratio 0.28, 95% CI 0.05-1.47). In conclusion, the results of this analysis suggest that BAS is effective in reducing TLR and improves clinical outcomes by reducing MI and MACE compared with PES.

Randomised comparison of titanium-nitride-oxide coated stents with bare metal stents: five year follow-up of the TiNOX trial

Revascularisation with Titanium-Nitride-Oxide (TiNOX) coated stents is safe and effective in patients with de novo native coronary artery lesions. In the TiNOX trial there was a reduction in restenosis and major adverse cardiac events as compared with stainless steel stents of otherwise identical design. The purpose of the present study was to evaluate the long-term outcome of these patients over five years.