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Effects of calcium hydroxide intracanal medicament on push-out bond strength of endodontic sealers: A systematic review and meta-analysis

Alhajj MN, Daud F, Al-Maweri SA, Johari Y, Ab-Ghani Z, Jaafar M, et al.

J Esthet Restor Dent, 2022 Dec;34(8):1166-1178.
PMID: 36239133 DOI: 10.1111/jerd.12974

OBJECTIVE: To investigate the effect of calcium hydroxide intracanal medicament on the push-out bond strength of resin-based and calcium silicate-based endodontic sealers.
METHODS: A comprehensive search of was conducted for all relevant in-vitro studies. All randomized controlled in-vitro studies that evaluated the effect of calcium hydroxide on the push-out bond strength of resin-based or calcium silicate-based endodontic sealers were assessed. The variables of interest were extracted, and the risk of the included studies was evaluated. The standardized mean difference was calculated and the significance level was set at p value <0.05.
RESULTS: A total of 26 studies were eligible for analysis. There were 45 independent comparison groups and 1009 recruited teeth. The pooled data showed no significant difference in push-out bond strength between calcium hydroxide and control group in the resin-based group (SMD = 0.03; 95% CI = -0.55, 0.60; p = 0.93), and calcium silicate-based group (SMD = 0.02; 95% CI = -0.31, 0.35; p = 0.90). Most of the studies (21 out of 26) were at medium risk of bias and five studies showed a low risk of bias.
CONCLUSION: The available evidence suggests that calcium hydroxide used as intracanal medication does not influence the push-out bond strength of the resin- and calcium silicate-based endodontic sealers.
CLINICAL SIGNIFICANCE: The results of this meta-analysis suggest that calcium hydroxide used as intracanal medication does not influence the push-out bond strength of resin-based and calcium silicate-based endodontic sealers.

Matched MeSH terms: Calcium Hydroxide/chemistry
Fulltext Effects of using pozzolan and Portland cement in the treatment of dispersive clay

Vakili AH, Selamat MR, Moayedi H

ScientificWorldJournal, 2013;2013:547615.
PMID: 23864828 DOI: 10.1155/2013/547615

Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone.

Matched MeSH terms: Calcium Hydroxide/chemistry*
Efficient removal of lignin with the maintenance of hemicellulose from kenaf by two-stage pretreatment process

Wan Azelee NI, Md Jahim J, Rabu A, Abdul Murad AM, Abu Bakar FD, Md Illias R

Carbohydr Polym, 2014 Jan;99:447-53.
PMID: 24274529 DOI: 10.1016/j.carbpol.2013.08.043

The enhancement of lignocellulose hydrolysis using enzyme complexes requires an efficient pretreatment process to obtain susceptible conditions for the enzyme attack. This study focuses on removing a major part of the lignin layer from kenaf (Hibiscus cannabinus) while simultaneously maintaining most of the hemicellulose. A two-stage pretreatment process is adopted using calcium hydroxide, Ca(OH)₂, and peracetic acid, PPA, to break the recalcitrant lignin layer from other structural polysaccharides. An experimental screening of several pretreatment chemicals, concentrations, temperatures and solid-liquid ratios enabled the production of an optimally designed pretreatment process for kenaf. Our results showed that the pretreatment process has provide 59.25% lignin removal while maintaining 87.72% and 96.17% hemicellulose and cellulose, respectively, using 1g of Ca(OH)₂/L and a 8:1 (mL:g) ratio of liquid-Ca(OH)₂ at 50 °C for 1.5 h followed by 20% peracetic acid pretreatment at 75 °C for 2 h. These results validate this mild approach for aiding future enzymatic hydrolysis.

Matched MeSH terms: Calcium Hydroxide/chemistry*
Reduction of mycotoxins in white pepper

Jalili M, Jinap S

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2012;29(12):1947-58.
PMID: 22971039 DOI: 10.1080/19440049.2012.719640

A simple method for the reduction of aflatoxins B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁), G₂ (AFG₂) and ochratoxin A (OTA) in white pepper was studied. Response surface methodology (RSM) was applied to determine the effect of four variables, which included time (20-60 min), temperature (30-70°C), calcium hydroxide (Ca(OH)₂) (0-1%) and hydrogen peroxide (H₂O₂) (1-3%) during the washing step of white pepper. The efficacy of the method was evaluated by the determination of mycotoxins by HPLC with fluorescence detection (FD). Statistical analysis showed that the experimental data could be adequately fitted into a second-order polynomial model, with a multiple regression coefficient (R²) in the range of 0.805-0.907 for AFG₂ and AFG₁, respectively. The optimal condition was 57.8 min, 62.0°C, of 0.6% (w/v) and 2.8% (v/v) for time, temperature, Ca(OH)₂ and H₂O₂ respectively. By applying the optimum condition, the mycotoxins reduction was found to be in the range of 68.5-100% for AFB₂ and AFG₁ respectively.

Matched MeSH terms: Calcium Hydroxide/chemistry
Development of a synthetic bone scaffold using porous hydroxyapatite for bone repair

Mustaffa R, Besar I, Andanastuti M

Med J Malaysia, 2008 Jul;63 Suppl A:95-6.
PMID: 19025001

In this study, porous hydroxyapatite (HA) samples were fabricated via sponge techniques with the aid of sago as part of the binder mixture. Development processes for the production of porous bone graft substitutes are studied using polyurethane sponge. To obtain the optimum amount of binder for successful fabrication of porous HA were done. Initially, porous HA powder was synthesized using calcium hydroxide and orthorphosphoric acid. Meanwhile, sago was mixed with PVA in a certain ratio to be used as binder for preparing the porous HA. After a series of investigative tests were conducted to characterize the sintered samples, the use of the sago and polymeric mixture was found to successfully aid the fabrication of porous HA samples. In this investigation, comparison of physical and mechanical characteristics between samples prepared using difference techniques was made.

Matched MeSH terms: Calcium Hydroxide/chemistry
Fulltext Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide

Sazwi NN, Nalina T, Abdul Rahim ZH

BMC Complement Altern Med, 2013;13:351.
PMID: 24330738 DOI: 10.1186/1472-6882-13-351

Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined.

Matched MeSH terms: Calcium Hydroxide/chemistry*