The α-amino acid ester acyltransferase (SAET) from Sphingobacterium siyangensis is one of the enzymes with the highest catalytic ability for the biosynthesis of l-alanyl-l-glutamine (Ala-Gln) with unprotected l-alanine methylester and l-glutamine. To improve the catalytic performance of SAET, a one-step method was used to rapidly prepare the immobilized cells (SAET@ZIF-8) in the aqueous system. The engineered Escherichia coli (E. coli) expressing SAET was encapsulated into the imidazole framework structure of metal organic zeolite (ZIF-8). Subsequently, the obtained SAET@ZIF-8 was characterized, and the catalytic activity, reusability and storage stability were also investigated. Results showed that the morphology of the prepared SAET@ZIF-8 nanoparticles was basically the same as that of the standard ZIF-8 materials reported in literature, and the introduction of cells did not significantly change the morphology of ZIF-8. After repeated use for 7 times, SAET@ZIF-8 could still retain 67% of the initial catalytic activity. Maintained at room temperature for 4 days, 50% of the original catalytic activity of SAET@ZIF-8 could be retained, indicating that SAET@ZIF-8 has good stability for reuse and storage. When used in the biosynthesis of Ala-Gln, the final concentration of Ala-Gln reached 62.83 mmol/L (13.65 g/L) after 30 min, the yield reached 0.455 g/(L·min), and the conversion rate relative to glutamine was 62.83%. All these results suggested that the preparation of SAET@ZIF-8 is an efficient strategy for the biosynthesis of Ala-Gln.
Escherichia coli/genetics* ; Glutamine ; Zeolites/chemistry* ; Amino Acids

OBJECTIVE: To compare the clinical effects of pulpotomy with two kinds of calcium silicate materials, and to evaluate the formation of dentin bridge and pulp calcification after pulpotomy of adult permanent teeth. METHODS: Patients who visited the General Department of Peking University School and Hospital of Stomatology from November 2017 to September 2019 and planned for pulpotomy on permanent premolars and molars with carious exposed pulp were selected. They were randomly divided into two groups. Bioceramic putty material iRoot BP (iRoot group, n=22) and mineral trioxide aggregate MTA (MTA group, n=21) were used as pulp capping agents, respectively. The patients were recalled after one year and two years. The clinical efficacy, dentin bridge index (DBI) and pulp calcification index (PCI) were recorded. Blinding method was used for the patients and evaluators. RESULTS: There was no significant difference in gender, mean age, dentition and tooth position between the two groups (P>0.05). Seven cases were lost during the first year (4 cases in iRoot group and 3 cases in MTA group). In the iRoot group, 1 case had transient sensitivity at the time of 1-year follow-up. The cure rate of the two groups was 100% at the time of 2-year follow-up. The proportion of dentin bridge formation was 38.9% one year after operation, 55.6% two years after operation. The proportion of partial or even complete disappearance of root canal image was 5.6% before operation, 38.9% and 55.6% one and two years after operation, respectively. The difference was statistically significant by rank sum test (P < 0.05). There was no significant difference in dentin bridge formation and pulp calcification between the two groups (P < 0.05). DBI and PCI after operation was as the same as those before operation (44.4% cases of DBI and 25% cases of PCI) or gradually increased (55.6% cases of DBI and 75% cases of PCI). Spearman's nonparametric correlation analysis showed that age was positively correlated with preoperative pulp calcification index (PCI0, P < 0.05), but not with the dentin bridge index (DBI1, DBI2), pulp calcification index (PCI1, PCI2) and the degree of change (DBI2 vs. DBI1, PCI1 vs. PCI0, PCI2 vs. PCI0) 1-year and 2-year after operation (P>0.05). CONCLUSION According to this study, good clinical effects were obtained within 2-year after pulpotomy of adult permanent teeth with MTA and iRoot. In some cases, the root canal system had a tendency of calcification aggravation, and there was no statistical difference in the development of this trend between the two groups.
Humans ; Adult ; Pulpotomy/methods* ; X-Rays ; Calcium Compounds/therapeutic use* ; Dentition, Permanent ; Molar/surgery* ; Treatment Outcome ; Silicates/therapeutic use* ; Aluminum Compounds/therapeutic use* ; Oxides ; Drug Combinations ; Dental Pulp Capping

OBJECTIVE: To evaluate the clinical characteristics and effectiveness of pulpotomy in mature permanent teeth with bioceramic putty repairmen iRoot and mineral trioxide aggregate (MTA). METHODS: Pulpotomy was performed on mature permanent premolars and molars with carious exposures at the Department of General Dentistry of Peking University School and Hospital of Stomatology, from November 2017 to September 2019. The patients were randomly divided into 2 groups, Group iRoot (n=22) and Group MTA (n=21). In Group iRoot, bioceramic putty repairmen iRoot was used as pulp capping agent, while in Group MTA, mineral trioxide aggregate was used as pulp capping agent. All the patients had signed informed consent forms. The clinical efficacy was evaluated by clinical examinations (temperature and electrical activity test) and imaging examinations 3, 6, and 12 months after surgery. Blinding was used for the patients and evaluators, but due to the obvious differences in the properties of the two pulp capping agents, the blinding method was not used for the treatment provider (the attending physician). RESULTS: There was no significant difference in gender, average age, dentition and tooth position distribution between the two groups (P>0.05). In the study, 7 cases were lost to follow-up 12 months after operation (4 cases in Group iRoot, and 3 cases in Group MTA). One case in each of the two groups had transient sensitivity at the end of the 3-month follow-up, and the pulp vitality was normal at the end of the 6-month follow-up. One case in Group iRoot showed sensitivity at the end of the 12-month follow-up. The success rates of the two groups at the end of 12-month follow-up were 100%, and the cure rates were 94.4% (Group iRoot) and 100% (Group MTA), respectively, and the difference was not statistically significant (P>0.05). No cases in Group iRoot had obvious crown discoloration, while 3 cases in Group MTA had. CONCLUSION The clinical characteristics and effectiveness of pulpotomy in mature permanent teeth with bioceramic putty repairmen iRoot were similar with MTA. Bioceramic putty repairmen iRoot is an acceptable material when used in pulpotomy of mature permanent teeth. Because it is not easy to cause tooth discoloration after treatment and is convenient to operate, bioceramic putty repairmen iRoot has a better clinical application prospect.
Aluminum Compounds/therapeutic use* ; Calcium Compounds/therapeutic use* ; Drug Combinations ; Humans ; Oxides/therapeutic use* ; Pulpotomy ; Silicates/therapeutic use* ; Treatment Outcome

OBJECTIVE: To evaluate the efficacy of iRoot BP Plus, a novel bioceramic material, and mineral trioxide aggregate (MTA) by comparing the clinical and radiographic results of pulpotomy in human primary molars, and to find out the influence factor. METHODS: Children who had at least one primary molar diagnosed as pulpitis, and received pulpotomy in the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology from January, 2017 to December, 2018 were searched by the selection criteria in the Electronic Medical Record Database of Peking University School and Hospital of Stomatology. The molars with the pulp capping agents were iRoot BP Plus or MTA were included, and the molars with other pulp capping agents were excluded. Molars using iRoot BP Plus were selected into the experimental group (iRoot BP Plus group). Molars using MTA were selected into the control group (MTA group) using propensity score matching model (1 ∶ 1), considering the gender, age, tooth position, the title of clinician, pulp status, restoration and length of follow-up as the potential influence factor. Basic information, the relevant medical records including symptoms, clinical and radiographic examination before and after operation, intraoperative information and follow up examination records were collected. The success rates were compared and the influence factors were analyzed respectively. RESULTS: The study included 132 children, 178 molars (89 molars from each group) and the mean follow-up time was (462±99) days by December, 2019. In the iRoot BP Plus group, 9 molars failed whilst 6 molars failed in MTA group. The success rate was 89.9% and 93.3%, respectively, showing no significant difference between the two groups. Through Cox proportional risk model analysis, the success rate of iRoot BP Plus was significantly lower when the pulp status was poor, while other factors including age, tooth position, title of clinician and restoration were not found to be associated with the clinical outcome. CONCLUSION Pulpotomy of human primary molars with iRoot BP Plus has the same effectiveness with MTA. The pulp status is the main factor that influences the outcome of iRoot BP Plus. Further studies with larger sample sizes and longer follow-up terms are needed.
Child ; Humans ; Pulpotomy/methods* ; Pulp Capping and Pulpectomy Agents ; Pemetrexed ; Silicates/therapeutic use* ; Aluminum Compounds/therapeutic use* ; Calcium Compounds ; Oxides ; Molar/surgery* ; Drug Combinations ; Treatment Outcome ; Tooth, Deciduous

Aims: This research was conducted to develop and characterize polyvinyl alcohol (PVA)/montmorillonite (MONT) clay incorporated with carvacrol (Carva) nanocomposite film as a potential material in wound dressing. Methodology and results: Organophilic MONT clay, which was initially modified from commercial MONT clay by cetyltrimethylammonium bromide (CTAB), was used in the polymerization process using PVA. The synthesized nanocomposites were visualized via transmission electron microscopy (TEM). The developed film (PVA/MONT/Carva nanocomposite film) was characterized via Fourier transform infrared (FTIR). The investigation on mechanical property and antimicrobial activity of the film was also performed. All nanocomposites are spherical, with a size of 92.8 ± 22.1 nm. The -OH stretch, C-H stretch, aromatic group, SiO stretch, and C-O from acetyl group were identified in the PVA/MONT/Carva nanocomposite films. During the chemical release test, carvacrol attained a plateau at 24 h, with a total release of 62.3%. This nanocomposite exhibited a severe detrimental influence on the growth of Gram-bacteria and yeasts, which represented a broad spectrum of antimicrobial agents. All test microorganisms showed approximately up to 82% reduction of microbial growth during the Hohenstein challenge test. Physically, the nanocomposite films were yellowish and apparent. The film was sturdy, flexible, elastic and consisted of excellent water holding capacity. Conclusion, significance and impact of study PVA/MONT/Carva nanocomposite film may have a useful potential to be merged in the pharmaceutical application, especially in wound dressing production.
Polyvinyl Alcohol ; Bentonite ; Wound Healing

OBJECTIVE: To evaluate the clinical characteristics and effectiveness of bioceramic putty repairment (iroot BP Plus) used as pulp capping agents on pulpotomy in primary molars. METHODS: Forty primary molars were treated by pulpotomy with bioceramic putty repairmen as the pulp capping agents at the Third Clinical Division of Peking University School and Hospital of Stomatology, from September 2016 to September 2017. The children who were followed up over one year were selected as the subjects of this study. The teeth were checked clinically and radiographically during fixed intervals, and classified into one of five outcomes: N, H, P₀, P_X, P_Y. N, absence of clinical symptoms, and absence of apical radiolucency; H, absence of clinical symptoms, and nonpathologic radiographic change present; P₀, absence of clinical symptoms, and pathologic change present, no need for treatment; P_X, present or absence of clinical symptoms, pathologic change present treatment or extract immediately; P_Y, premature loss of deciduous tooth. Molars classified into N and H were regarded as successful, classified into P₀, P_X and P_Y were regarded as failed. RESULTS: Followed up for 12-24 months (the average follow up time was 16months), thirty four children were finally included, aged from 3.1 years to 8.5 yaers (the average age was 4.3 years), forty primary molars were included. Thirty four primary molars were included into N group, with absence of clinical symptoms, absence of apical radiolucency. Two molars were included into H group with physiological root absorption. One molar was included into P₀group with absence of clinical symptoms butinternal absorption of the root. Three molars were included into P_X group, with gingival fistula and apical radiolucency. None was included into P_Y group. Thirty six teeth got successful treatment, four molars failed. One year success rate of pulpotomy of primary molars using bioceramic putty repairment was 95%. CONCLUSION Current evidence suggests that bioceramic putty repairment as a pulpotomy medicament showed satisfied clinical and radiographic result in pulpotomy of primary molars. Bioceramic putty repairment is an acceptable material when used in pulpotomy of primary molars.
Aluminum Compounds ; Calcium Compounds ; Ceramics ; Child ; Child, Preschool ; Follow-Up Studies ; Humans ; Molar ; Oxides ; Pulpotomy ; Silicates ; Tooth, Deciduous ; Treatment Outcome

OBJECTIVE: To evaluate the effect of mineral trioxide aggregate (MTA) and propolis from Shangdong province on the cell viability, mineralization and migration and anti-inflammatory ability of dental pulp fibroblasts. METHODS: The human dental pulp fibroblasts were cultured and subjected to 10 mg/L of propolis and 1:8 dilution of MTA extraction. The cell viability was evaluated with cell counting kit-8 (CCK-8) after 1, 5, 7 and 9 days. The cells in the upper inserts and the test culture media on the bottoms of 24-well plates interacted for 15 hours. Then the numbers of cells migrated through the permeable membranes were compared. The cells seeded in the 24-well plates were incubated in osteogenic medium with different materials for 21 days and stained with alizarin red S, then photographed. To evaluate the deposition of calcified matrix, the wells were destained with 100 mmol/L cetylpyridinium chloride. Finally, the cells were exposed to 1 mg/L lipopolysaccharide (LPS) to induce an inflammatory response, in the presence of propolis, MTA extraction. The cells were collected after 3 h, and the expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were determined using real-time polymerase chain reaction (real-time PCR). Statistical analysis was performed by one-way ANOVA and nonparametric tests (P<0.05). RESULTS: The cell viability of propolis group was significantly lower than those of MTA and control groups on days 5, 7 and 9, while MTA significantly increased the numbers of the viable cells on days 7 and 9. The migration cells of propolis group (26.67±2.52) were fewer than control group (61.33±4.93), and the cells of MTA group (80.00±2.65) were statistically more than those of the other two groups. The propolis group significantly induced more calcified matrix deposition than MTA group after 21 days of culture. Propolis significantly suppressed the expressions of IL-1β and IL-6 after LPS exposure compared with MTA and control groups. CONCLUSION The propolis from Shandong compared with MTA showed a certain degree of cytotoxicity, and had no significant effect on cell migration. On the other hand, propolis exhibited significant anti-inflammatory and mineralization promotion effect, suggesting that the active ingredients of propolis could be introduced as a supplement of pulp capping materials, or used as an irrigant or intracanal medicament due to its excellent anti-inflammatory effect. Propolis may have potential in vital pulp treatment of young permanent tooth suffering pulp inflammation.
Aluminum Compounds ; Calcium Compounds ; Dental Pulp ; Drug Combinations ; Fibroblasts ; Humans ; Oxides ; Plant Extracts ; Propolis ; Silicates

OBJECTIVE: To investigate the effect of smear layer on apical sealing ability in teeth obturated with mineral trioxide aggregate (MTA) Plus as retrofilling materials. METHODS: Fifty freshly extracted maxillary anterior teeth or premolars with single root canal were used in this study. All teeth were instrumented to master apical point 60# by using the stepback technique, obturated with lateral condensation technique, and then apical resected. A rootend cavity was then instrumented with an ultrasonic diamond-coated tip. Then the selected teeth were randomly and equally divided into two groups (n=25). In the experimental group (smear-), the teeth were irrigated with 0.17 g/L ethylenediaminetetraacetic acid (EDTA) to remove smear layer on the root-end cavity wall; in the control group (smear+), the teeth were irrigated with physiological saline. Five teeth were extracted to evaluate the cleanliness of root end cavity walls under a videomicroscope, respectively. The scanning electron microscope (SEM) evaluation was also performed for the presence of smear layer and open tubule. For the additional 40 teeth, the root-end cavities were filled with MTA Plus. The quantitative apical leakage of each teeth was evaluated by measuring the concentration of leaked sucrose in apical reservoir on 1, 7, 14, 21, 28, 35, 42, 49 and 56 days, respectively. The samples were stored at 37 °C and 100% humidity for 56 days. Statistical analysis was done with ANOVA for repeated measurement design data. RESULTS: Removal of the smear layer did not cause significantly less apical leaked sucrose than that when the smear layer was left intact for 56 days (P>0.05). There were statistically significant differences at the concentration of leaked sucrose among different observation time points (P<0.05). CONCLUSION It may be concluded that removing the smear layer may not be necessary in root-end cavities filled with MTA Plus.
Aluminum Compounds ; Calcium Compounds ; Dental Leakage ; Drug Combinations ; Edetic Acid ; Oxides ; Root Canal Filling Materials ; Root Canal Irrigants ; Root Canal Preparation ; Root Canal Therapy ; Silicates ; Smear Layer ; Sucrose/pharmacokinetics*

OBJECTIVE: To investigate the physical and chemical properties of pulp capping materials based on bioactive glass (BG). METHODS: Novel BG pulp capping materials were composed of powder and fluid. The powder was BG (82.36% SiO₂, 15.36% CaO, and 2.28% P₂O₅) synthesized by using the sol-gel method combined with template technology. Two kinds of fluid were provided: (1) phosphate buffer (PB) solution and (2) phosphate buffer solution with 1% sodium alginate (SA) addition. After mixing the powder and fluid, BG-PB and BG-PB-SA were prepared. Setting time and compressive strength of the BG pulp capping materials were tested by setting time loading system and mechanical testing machine. Statistical analysis was performed using the independent sample t-test, with the significance set at 0.05. pH meters was used to test the pH of the BG pulp capping materials and mineral trioxide aggregate (MTA). The sealing ability of the BG pulp capping materials and MTA was tested by methylene blue dye leakage model. Statistical analysis was performed using one-way ANOVA analysis and LSD multiple comparison, with the significance set at 0.05. RESULTS: (1) Setting time: the initial and final setting time of BG-PB were (7.2±0.3) min and (12.7±0.9) min, respectively. And the initial and final setting time of BG-PB-SA was (7.5±0.3) min and (13.6±1.6) min. There was no significant difference between BG-PB and BG-PB-SA groups (P>0.05). (2) Compressive strength: the compressive strength of BG-PB was (16.5±1.8) MPa at 1 day and (14.1±3.7) MPa at the end of 28 days. However, the compressive strength of BG-PB-SA was (26.6±6.3) MPa on day 1 and (21.6±5.6) MPa on day 28, which was significantly higher than that of BG-PB (P<0.05). (3) pH: the pH of BG pulp capping materials' bulk immersed in simulated body fluid (SBF) went up to 8.06, and the highest pH of MTA was 8.47. Significant difference was observed between the BG pulp capping materials and MTA (P<0.05). (4) Sealing ability: the optical density (D) in positive control group was significantly higher than ln BG-PB, BG-PB-SA and MTA groups (P<0.05). And BG-PB and BG-PB-SA showed the similar favorable sealing ability with MTA, and no significant difference was observed among the three groups (P>0.05). CONCLUSION The novel BG pulp capping materials showed good physical properties, especially BG's setting time was short; BG pulp capping materials are promising.
Aluminum Compounds ; Calcium Compounds ; Compressive Strength ; Dental Pulp Capping ; Glass ; Materials Testing ; Oxides ; Silicates ; Silicon Dioxide

OBJECTIVE: To evaluate the effect of acid etching of retropreps on seal of different retrofill materials. METHODS: In the study, 80 freshly extracted lower molar teeth were used. They were examined under 3.5× magnifying glass to rull out fractures. They were cleaned and stored in distilled water before use. The distal roots were sectioned off and underwent root canal treatment. Rotary nickel-titanium instruments were used during instrumentation and the roots were obturated using lateral condensation technique. The apical portion (3 mm in length) was removed with a fine grit diamond bur, the root tip was retroprepared with a ultrasonic tip (3 mm in depth). The retroprepared roots were randomly assigned to 4 groups and retrofilled with amalgam, intermediate restorative material (IRM), iRoot BP Plus and mineral trioxide aggregate (MTA). The groups were further divided into subgroups according to treatment of the root end cavity (etch and non-etch). The root tips were covered with alginate impression material and were left to set in PBS solution for a week and stained with methylene blue for a week. The roots were removed from the dye solution, thoroughly rinsed and dried, split in halves along the long axis with a diamond disk and observed under a stereoscope. The linear dye leakage was measured and analyzed. One way ANOVA and Tamhane's T2 method were used to analyze the data. The significance level was set at 0.05. RESULTS: The dye leakage results (mean±standard deviation) according to the treatment groups were: amalgam etch (2.80±0.72) mm, amalgam non-etch (2.07±0.86) mm, IRM etch (1.54±0.19) mm, IRM non-etch (1.12±0.28) mm , iRoot BP Plus etch (0.20±0.20) mm, iRoot BP Plus non-etch (0.11±0.08) mm, MTA etch (0.19±0.19) mm, and MTA non-etch (0.17±0.14) mm. One way ANOVA showed significant differences between the groups. Comparison between the groups using Tamhane's T2 method showed roots retrofilled with iRoot BP Plus and MTA had significant less leakage than those retrofilled with amalgam and IRM (P<0.05); There was no significant difference in terms of leakage between iRoot BP Plus and MTA; Acid etching increased leakage of IRM but did not affect MTA, iRoot BP Plus or amalgam retrofillings. CONCLUSION Acid etching is not shown to benefit apical sealing of retrofill materials.
Aluminum Compounds ; Calcium Compounds ; Dental Leakage ; Drug Combinations ; Oxides ; Random Allocation ; Root Canal Filling Materials ; Root Canal Therapy ; Silicates ; Tooth Root