A Comparison of Zirconia and Titanium Abutments for Microleakage
Bibliographic record
Abstract
BACKGROUND: Microleakage through the interface has been documented in implant systems with titanium (Ti) abutments. There is a current increase in the use of zirconia (Zi) abutments especially in esthetic zone in where higher risk of visible metal color through the peri-implant tissues exists. PURPOSE: The aim of the present in vitro study is to evaluate the leakage at the implant fixture-abutment interface with two different screw-retained abutment systems at different torque values in a nonloading condition. MATERIALS AND METHODS: In vitro study design included four groups (Ti and Zi torqued at 25 and 15 Ncm [N = 8/group]). Microcomputed tomography (micro-CT) was chosen to detect microgap. Microleakage from the implant chamber to the external milieu was evaluated using limulus amebocyte lysate (LAL) test, while microleakage from external milieu to the implant chamber was evaluated using toluidine blue dye (TBD) and colorimeter. RESULTS: Micro-CT images did not reveal any microgap. LAL test showed that there is a time-, abutment-, and torque-dependent increase in microleakage (p = .001) with Zi torqued at 15 Ncm having higher leakage with time compared with Ti torqued at 15 Ncm (p = .002), as well as Zi torqued at 15 Ncm having higher leakage with time compared with Zi torqued at 25 Ncm (p = .01). TBD test showed a nonsignificant increase in microleakage with higher leakage related to titanium abutment groups (p > .05). Repeated torque/antitorque handling differentially affected microleakage (p = .01). CONCLUSIONS: Within the limits of this study, there is a statistically significant difference in bidirectional microleakage with time, abutment type, and torque values being major players for leakage from internal implant chamber to external milieu, while the abutment type and time but not the torque value being important factors for leakage from external milieu into implant chamber in nonloading condition. Future studies are needed to determine peri-implant health around Zi abutments.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".