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ePaper created 2018-01-31, 10:01:59 | version 1.38.0
research | – Statistical analysis: Values were recorded as mean ± standard deviation (SD) and median. The non-para- metric Friedman test was applied to compare sample values. The level of significance was set at p < 0.05. The success of immediately placed implants has been investigated in various studies with encourag- ing results already. But what is rather simple in the an- terior mandible needs more attention when it comes to the anterior maxilla. Here, clinicians are oftentimes concerned not only about achieving adequate im- plant stability, but also about fulfilling patients’ desires for aesthetic results that resemble the natural denti- tion. To shorten procedures and eliminate intermedi- ate prosthetic steps, digital technologies were devel- oped that allow the intraoral scanning of models and attachments with a high degree of precision and re- producibility. Rationale for immediate restoration Research has shown that, for two-stage implants, marginal bone loss occurs primarily during the first year following placement and that this has mainly been at- tributed to the establishment of biologic width adjacent to the implant.19 Some studies have shown that bone re- modelling can be biologically ascribed to bacterial col- onisation of the micro leakage present in a two-stage implant system and subsequent inflammation.20 The crestal bone loss around implants has both horizontal and vertical components. Following abutment connec- tion, crestal bone has been shown to recede from the implant/abutment junction microgap by 1.3 to 1.4 mm, measured horizontally.21 Animal study Immediate implant placement and restoration minimise the harmful contamination of the peri- implant biological space and the resultant bone resorption. Immediate load- ing requires that certain prerequisites are met. The best way to objectively quantify the feasibility of immediate loading clinically is to analyse implant stability either by measuring the insertion torque, recommended at above 30 Ncm, or using the Osstell Mentor ultrasonic stability measuring device that returns ISQ values, which if above 65–70 allow us to load immediately with some confi- dence (Tab. 1). Changes in the peri-implant tissue can be quantified by histomorphometry and histological evaluation in ex- perimental studies (Tabs. 2 & 3). The radiological re- sults of the animal experiments are documented in Fig- ures 5a & b and Table 4. The histological connection between the soft tissue and the SKY elegance abut- ment is tight. In combination with platform switching, this produces a high level of bone stability at the implant collar (Figs. 6a & b). ISQ value Insertion p value Mean ± Sd Median BioHPP abutment 74.46 ± 4.55 74.46 Titanium abutment 74.19 ± 4.29 74.19 0.16 0.23 Tab. 1: Friedman test of ISQ analysis and measurements at initial day. Results as mean and medians. No significant differences with p < 0.05 were found. BIC (%) Titanium PEEK p value Mean ± Sd 61.29 ± 1.45 62.52 ± 4.63 0.32 Median 61.29 62.52 Tab. 2: Friedman test of BIC values. Comparison between titanium and hybrid PEEK-Ti abut- ments. Follow-up eight weeks after implant placement. Data shows mean, Sd and medians. No significant differences with p < 0.05 were found. Titanium PEEK p value PM-BC Mean ± Sd 2.74 ± 0.41 3.11 ± 0.26 * 0.032 Median 2.74 3.11 PM-LC Mean ± Sd 2.91 ± 0.03 3.71 ± 0.18 * 0.008 Median 2.91 3.71 PM buccal-IS Mean ± Sd 2.35 ± 0.87 2.95 ± 0.53 * 0.015 Median 2.35 2.95 PM lingual-IS Mean ± Sd 2.65 ± 0.43 3.57 ± 0.38 * 0.003 Median 2.65 3.57 IS-BC Mean ± Sd 2.04 ± 0.11 * 1.53 ± 0.21 0.011 Median 2.04 1.53 IS-LC Mean ± Sd 1.93 ± 0.14 * 1.41 ± 0.19 0.029 Median 1.93 1.41 Linear measurements in millimetre: PM-BC: distance from the peri-implant mucosa to the buccal bone crest; PM-LC: distance from the peri-implant mucosa to the lingual bone crest; PM buccal-IS: distance from peri-implant mucosa to the implant shoulder in the buccal aspect; PM lingual-IS: distance from peri-implant mucosa to the implant shoulder in the lingual aspect; IS-BC: distance from the top of the implant shoulder to the first bone-to-implant contact in the buccal aspect; IS-LC: distance from the top of the implant shoul- der to the lingual bone crest. Values as mean ± Sd and median. Tab. 3: Non-parametric Friedman test to related samples. (*) Significant differences with p < 0.05. CAD/CAM 1 2018 11