Acidic <scp>pH</scp> weakens the microhardness and microstructure of three tricalcium silicate materials
Bibliographic record
Abstract
AIM: To investigate the microhardness and microstructural features of three tricalcium silicate materials: mineral trioxide aggregate (MTA), Endosequence Root Repair Material Putty (ERRM Putty) and Endosequence Root Repair Material Paste (ERRM Paste), after exposure to a range of acidic environments in comparison with intermediate restorative material (IRM). METHODOLOGY: Endosequence Root Repair Material Putty (Brasseler, Savannah, GA, USA), ERRM Paste (Brasseler, Savannah, GA, USA), MTA (ProRoot; Dentsply Tulsa Dental, Johnson City, TN, USA) and IRM (Dentsply Caulk, Milford, DE, USA) were set in cylindrical rubber moulds as four groups containing twenty specimens each. Fifteen specimens per each material were randomly distributed into three groups (n = 5) to be exposed to butyric acid buffered at three different pH levels (5.4, 6.4 and 7.4) for 7 days. The remaining five specimens were exposed to distilled water as a control group. The surface microhardness after exposure either to acid or to water was measured after 7-days at 37 °C. The morphology of the internal microstructure was observed using a scanning electron microscope (SEM). Two-way univariate analysis of variance (anova) was applied to evaluate the Vickers microhardness value (VHN). RESULTS: The microhardness values of the materials were significantly higher in the neutral environment of butyric acid at pH 7.4 compared to those in the acidic condition of pH 5.4 for all groups (P < 0.001). MTA, ERRM Putty and ERRM Paste had higher microhardness values than IRM at all pH levels (P < 0.001). Specimens exposed to distilled water displayed significantly higher microhardness values than those values obtained in the presence of butyric acid buffered to all pH levels (P < 0.001). A more porous microstructure was observed following exposure to butyric acid at pH 5.4 than at pH 7.4. Several types of crystalline structures were formed by recrystallization, especially at pH 7.4 in all groups except for IRM. CONCLUSIONS: The microhardness values of ERRM Putty, ERRM Paste and MTA were reduced in an acidic environment, which resulted in these materials having more porous and less crystalline microstructures. MTA seems the most suitable material for application to an area of inflammation where a low pH value may exist.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".