Comparation of the effectiveness of conventional needle irrigation and photon-induced photoacoustic streaming with sodium hypochorite in the treatment of teeth with apical periodontitis: a randomized clinical trial.

Photon-initiated photoacoustic streaming (PIPS) with an Er: YAG laser has been introduced in root canal treatment to improve irrigation and facilitate the removal of bacteria in the root canal system. This study aimed to compare the antibacterial effectiveness of two different root canal irrigation techniques, conventional needle irrigation (CNI) and PIPS, using 1% sodium hypochlorite (NaOCl), in the treatment of teeth with apical periodontitis. Sixty patients with a total of sixty teeth affected by apical periodontitis were included in this study. The teeth underwent root canal therapy, and after mechanical instrumentation, they were randomly assigned to two groups (n = 30) based on the final irrigation protocol: CNI or PIPS with 1% NaOCl. Bacterial suspensions in the root canals were evaluated using Adenosine 5'-triphosphate (ATP) assay kit after mechanical instrumentation and after final irrigation. Then, a follow-up was conducted after 7 days. The results revealed that final irrigation significantly reduced ATP values in both the CNI and PIPS groups (P < 0.001). The ATP values after final irrigation was greater in the CNI group compared to the PIPS group (P < 0.001). After a 7-day follow-up, percussion tenderness and fistula were significantly resolved in both groups (P < 0.05). A multivariate linear regression model was used to identify the factors that influence post irrigation ATP values. The analysis demonstrated that pre-operative percussion tenderness (P = 0.006), the presence of a fistula (P < 0.001) and the method used in the final irrigation (P < 0.001) had a significant impact on the ATP value after final irrigation. These results indicate that employing PIPS with 1% NaOCl as the final irrigation protocol exhibited superior antibacterial effectiveness and has the potential to enhance clinical outcomes in the treatment of teeth afflicted with apical periodontitis.

Effect of chitosan and CMCS on dentin after Er:YAG laser irradiation: shear bond strength and surface morphology analysis.

OBJECTIVES: The aim of the present study was to evaluate the effect of chitosan and carboxymethyl chitosan (CMCS) on dentin surface morphology and bonding strength after irradiation of Er:YAG laser. METHODS: Eighty-four laser-irradiated dentin samples were randomly distributed into three groups (n = 28/group) according to different surface conditioning process: deionized water for 60s; 1wt% chitosan for 60s; or 1wt% CMCS for 60s. Two specimens from each group were subjected to TEM analysis to confirm the presence of extrafibrillar demineralization on dentin fibrils. Two specimens from each group were subjected to morphological analysis by SEM. Seventy-two specimens (n = 24/group) were prepared, with a composite resin cone adhered to the dentin surface, and were then randomly assigned to one of two aging processes: storage in deionized water for 24 h or a thermocycling stimulation. The shear bond strength of laser-irradiated dentin to the resin composite was determined by a universal testing machine. Data acquired in the shear bond strength test was analyzed by one-way ANOVA with the Tukey honestly significant difference post hoc test and Independent Samples t-test (α = 0.05). RESULTS: CMCS group presented demineralized zone and a relatively smooth dentin surface morphology. CMCS group had significantly higher SBS value (6.08 ± 2.12) without aging (p < 0.05). After thermal cycling, both chitosan (5.26 ± 2.30) and CMCS group (5.82 ± 1.90) presented higher bonding strength compared to control group (3.19 ± 1.32) (p < 0.05). Chitosan and CMCS group preserved the bonding strength after aging process (p > 0.05). CONCLUSIONS: CMCS has the potential to be applied in conjunction with Er:YAG laser in cavity preparation and resin restoration.

MicroRNA-155 expression is associated with pulpitis progression by targeting SHIP1.

BACKGROUND: Pulpitis is a commonly seen oral inflammation condition in clinical practice, it can cause much pain for the patient and may induce infections in other systems. Much is still unknown for the pathogenic mechanism of pulpitis. In this work, we discovered that the expression of miR-155 was associated with dental pulpal inflammation both in vivo and in vitro. METHODS AND RESULTS: Our experiments of LPS stimulated odontoblast cell line MDPC-23 showed miR-155 could act as a positive regulator by increasing the production of pro-inflammatory cytokines IL-1ß and IL-6 during inflammatory responses, whereas knockdown of miR-155 can reverse the effects. Bioinformatics analysis demonstrated that SHIP1 is a direct target of miR-155 in odontoblasts, this result was further verified at both mRNA and protein level. Inhibition of miR-155 resulted in the downregulation of inflammation factors, while co-transfection of si-SHIP1 and miR-155 inhibitor promoted the inflammatory responses. Treatment with miR-155 mimic or si-SHIP1 up-regulated the protein level of p-PI3K and p-AKT. By contrast, miR-155 inhibitor exerted the opposite effects. miR-155 mimics could upregulate the gene expression of IL-1ß and IL-6. Co-transfection of LY294002 and miR-155 mimic attenuated the inflammatory responses. Consistent with in vitro results, miR-155-/- mice could alleviate inflammatory response, as well as decrease the activation of p-PI3K and p-AKT, whereas increase the activation of SHIP1. CONCLUSIONS: Our data revealed a novel role for miR-155 in regulation of dental pulpal inflammatory response by targeting SHIP1 through PI3K/AKT signaling pathway.

Influence of sodium hypochlorite concentration on cavitation effect and fluid dynamics induced by photon-induced photoacoustic streaming (PIPS): A visualization study.

PURPOSE: The aim of the present study was to visualize and compare the cavitation effect and fluid dynamics induced by photon-induced photoacoustic streaming (PIPS) using sodium hypochlorite (NaOCl) with different concentrations as irrigant. METHODS: Forty artificial root canals were prepared using MTWO Niti file up to size #25/.06. The canals were randomly divided into four groups (n = 10/group). High-speed camera was used to visualize and compare the cavitation effect induced by PIPS in the artificial root canals containing saline or NaOCl. Fluid velocity and Reynolds number of saline, 1%-, 2.5%- and 5.25% NaOCl irrigants induced by PIPS in the apical region were calculated using TEMA 2D software while the fluid motions were recorded. RESULTS: Visualization profile revealed that NaOCl presented a stronger cavitation effect and fluid dynamics than saline during PIPS activation. In the apical region, 1% NaOCl group presented the highest average velocity of 3.868 m/s, followed by 2.5% NaOCl group (3.685 m/s), 5.25% NaOCl group (2.353 m/s) and saline group (1.268 m/s), corresponding to Reynolds number of 1653.173, 1572.196, 995.503 and 477.692. Statistically higher fluid velocity was calculated in 1% and 2.5% NaOCl groups compared to saline group, respectively (p < 0.05). CONCLUSIONS: The application of NaOCl and its concentration significantly influence the cavitation effect and fluid dynamics during PIPS activation. 1% and 2.5% NaOCl groups presented a more violent fluid motion in the apical region when activated by PIPS.

Long-term porosity and retreatability of oval-shaped canals obturated using two different methods with a novel tricalcium silicate sealer.

OBJECTIVE: To evaluate the percentage volume of voids and gaps in oval-shaped canals obturated using two different methods with a tricalcium silicate-based sealer after short- or long-term storage. The long-term effect of storage on the efficiency of removing filling material was also investigated. MATERIALS AND METHODS: Forty premolar teeth with oval-shaped canals were instrumented to Reciproc R25 and obturated using single cone obturation (SCO) or warm vertical compaction (WVC) techniques with gutta-percha and HiFlow sealer. The specimens were stored at 100% humidity and 37°C for 2 weeks or 6 months and scanned using micro-computed tomography. Initial retreatment was performed up to a Reciproc R40, and the operating time was recorded. The residual material in the canal received a supplementary procedure using XP-endo Finisher R (XPFR) files. After each retreatment procedure, the specimens were rescanned. RESULTS: The percentage volume of voids and gaps in the SCO group was higher than that of the WVC group at both 2 weeks and 6 months (P < 0.05). The percentage volume of the filling material removed after initial retreatment and XPFR cleaning was significantly higher in the 6-month group than in the 2-week groups (P < 0.05). The proportion of the residual material decreased significantly when XPFR files were used, compared to the initial retreatment group (P < 0.05) in both storage times. CONCLUSION: The efficiency of retreatment in the oval-shaped canal was closely related to the storage time rather than the filling technique using a tricalcium silicate sealer. The XPFR instrument proved effective in the removal of the remaining materials from the oval-shaped canal. CLINICAL RELEVANCE: Obturation of the oval-shaped canal with TSBS using the SCO technique in the coronal area needs to be optimized. The retreatment was less efficacious in freshly filled canals than aged filled canals.

Effect of Enterococcus faecalis OG1RF on human calvarial osteoblast apoptosis.

BACKGROUND: Enterococcus faecalis is a dominant pathogen in the root canals of teeth with persistent apical periodontitis (PAP), and osteoblast apoptosis contributes to imbalanced bone remodelling in PAP. Here, we investigated the effect of E. faecalis OG1RF on apoptosis in primary human calvarial osteoblasts. Specifically, the expression of apoptosis-related genes and the role of anti-apoptotic and pro-apoptotic members of the BCL-2 family were examined. METHODS: Primary human calvarial osteoblasts were incubated with E. faecalis OG1RF at multiplicities of infection corresponding to infection time points. Flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay, caspase-3/-8/-9 activity assay, polymerase chain reaction (PCR) array, and quantitative real-time PCR were used to assess osteoblast apoptosis. RESULTS: E. faecalis infection increased the number of early- and late-phase apoptotic cells and TUNEL-positive cells, decreased the mitochondrial membrane potential (ΔΨm), and activated the caspase-3/-8/-9 pathway. Moreover, of all 84 apoptosis-related genes in the PCR array, the expression of 16 genes was upregulated and that of four genes was downregulated in the infected osteoblasts. Notably, the mRNA expression of anti-apoptotic BCL2 was downregulated, whereas that of the pro-apoptotic BCL2L11, HRK, BIK, BMF, NOXA, and BECN1 and anti-apoptotic BCL2A1 was upregulated. CONCLUSIONS: E. faecalis OG1RF infection triggered apoptosis in human calvarial osteoblasts, and BCL-2 family members acted as regulators of osteoblast apoptosis. Therefore, BCL-2 family members may act as potential therapeutic targets for persistent apical periodontitis.

The antibacterial efficacy of photon-initiated photoacoustic streaming in root canals with different diameters or tapers.

BACKGROUND: In recent years, the concept of minimally invasive endodontics has been proposed, which could be described as preventing or treating diseases by preserving more dental tissue and creating minimal damage. In the process of root canal preparation, it was recommended to use instruments with a smaller taper to preserve more tooth tissue and improve the preservation rate of the affected teeth. Photon-induced photoacoustic streaming (PIPS) was a new type of laser-activated irrigation technology, which was now widely used in endodontic treatment. The purpose of this article was to evaluate the bactericidal effect of PIPS with NaOCl in root canals with different widths or tapers. METHODS: Twenty-three maxillary first molars with three independent root canals were included in this study. The mesiobuccal (MB), distobuccal (DB), and palatal (P) root canals were prepared at sizes of #10/.02, #25/.02, and #25/.06, respectively. After being incubated with a bacterial suspension for 4 weeks, the specimen were irrigated with 2% NaOCl activated by conventional needle irrigation (CNI) (n = 10) or PIPS (n = 10). Three specimen were not treated (control group). Before and after irrigation, the presence of bacteria was assessed with an adenosine 5'-triphosphate (ATP) assay kit and biofilms were assessed using confocal laser scanning microscopy and scanning electron microscopy. RESULTS: In specimen prepared using PIPS irrigation, the ATP was reduced by more than 98%. When the root canal taper was 0.02, the size #25 root canals had a higher percentage of dead bacteria than the size #10 root canals in all regions (P < 0.05) in the PIPS group. When the root canal width was #25, the 0.02 taper group had a higher percentage of dead bacteria than the 0.06 taper group in the apical region (P < 0.05), except coronal and middle regions (P > 0.05). PIPS irrigation results in a greater percentage of dead bacteria and reduction of ATP in size #10/.02 root canals than CNI in size #25/.06 root canals in three regions (P < 0.05). CONCLUSION: Increasing the width from #10 to #25 improves the bactericidal effect of PIPS in the root canal. Increasing the taper of the root canal from 0.02 to 0.06 at size #25 did not affect the bactericidal effects of PIPS. PIPS resulted in more dead bacteria in specimen with smaller tapers and root canal widths than CNI. PIPS can be used to clean the smear layer in the coronal region and open the dentin tubules. CLINICAL SIGNIFICANCE: Activation of irrigants with PIPS brought about significant bacterial reduction smaller tapers and width root canals compared to CNI, which was beneficial to prevent excessive loss of tooth tissue and conserve the structural integrity of teeth.

Effectiveness of photon-initiated photoacoustic streaming in root canal models with different diameters or tapers.

BACKGROUND: This study aimed to compare the use of photon-initiated photoacoustic streaming (PIPS) and conventional needle irrigation (CNI) in conjunction with different concentrations of sodium hypochlorite (NaOCl) to remove Enterococcus faecalis (E. faecalis) suspended bacteria and biofilms from root canal systems with different diameters or tapers. METHODS: Artificial root canal samples (n = 480) were randomly divided into three groups (n = 160/group). The canals were prepared to fit file sizes #10/.02, #25/.02, or #25/.06. The size #10/.02 group was incubated for seven days. The size #25/.02 or #25/.06 group was incubated for 2 days. A stable biological model of E. faecalis infection was established. The root canals were washed with distilled water or with 1%, 2%, or 5.25% NaOCl combined with CNI or PIPS. Bacterial suspensions and biofilms were assessed using an ATP assay kit and fluorescence microscopy. Image-Pro Plus was used to analyse the average fluorescence intensity to determine the most suitable root canal irrigation solution. RESULTS: In the CNI and PIPS groups, the ATP value of the 5.25% NaOCl subgroup was the lowest, followed by that of the 2% and 1% NaOCl subgroups. The ATP value of the distilled water subgroup was the highest (P < 0.05). When the root canal taper was 0.02, the ATP value of the #10/.02 + PIPS group was significantly lower than that of the #25/.02 + CNI group (P < 0.05). The average fluorescence intensity of the #10/.02 + PIPS group was lower than that of the #25/.02 + CNI group (P < 0.05). When the apical diameter was #25, the ATP value of the 0.02 taper in the PIPS group was lower than that of the 0.06 taper in the CNI group (P < 0.05), and the average fluorescence intensity of the 0.02 taper + PIPS group was lower than that of the 0.06 taper + CNI group (P < 0.05). PIPS combined with 2% and 5.25% NaOCl effectively improved the long-term antibacterial effect after irrigation and re-culture for 6 h. CONCLUSIONS: Compared with CNI, PIPS has greater ability to remove bacteria in root canals with a small preparation diameter and a small taper. PIPS with 2% and 5.25% NaOCl exhibited superior antibacterial and bacteriostatic effects.

Impacts of contracted endodontic cavities compared to traditional endodontic cavities in premolars.

BACKGROUND: This study aims to compare the percentage of dentin removed, instrumentation efficacy, root canal filling and load at fracture between contracted endodontic cavities, and traditional endodontic cavities on root canal therapy in premolars. METHODS: Forty extracted intact human first premolars were imaged with micro-CT and randomly assigned to the contracted endodontic cavity (CEC) or traditional endodontic cavity (TEC) groups. CEC was prepared with the aid of a 3D-printed template, canals were prepared with a 0.04 taper M-Two rotary instrument, and cavities were restored with resin. Specimens were loaded to fracture in an Instron Universal Testing Machine after a fatigue phase. The data were analyzed by the independent samples T test and Mann-Whitney U test, appropriate post hoc tests. RESULTS: In the premolars tested in vitro, the percentage of dentin removed in the premolars with two dental roots in the CEC group (3.85% ± 0.42%) was significantly smaller (P < 0.05) than in the TEC group (4.94% ± 0.5%). The untouched canal wall (UCW) after instrumentation for TECs (16.43% ± 6.56%) was significantly lower (P < .05) than the UCW (24.42% ± 9.19%) for CECs in single-rooted premolars. No significant differences were observed in the increased canal volume and surface areas in premolars between the TEC and CEC groups (P > 0.05). CECs conserved coronal dentin in premolars with two dental roots but no impact on the instrument efficacy. There were no differences between the CEC groups and the TEC groups in the percentage of filling material and voids (P > 0.05). In addition, the mean load at failure of premolars did not significantly differ between the CEC and TEC groups and there was no significant difference in the type of fracture (P > 0.05). CONCLUSION: The results of this study suggest that CEC could not improve the fracture resistance of the endodontically treated premolars. The instrumentation efficacy and the percentage of filling material did not significantly differ between CECs and TECs in premolars.

A novel method for periapical microsurgery with the aid of 3D technology: a case report.

BACKGROUND: Three-dimensional (3D) technology has gained wide acceptance in dentistry. It has been used for treatment planning and surgical guidance. This case report presented a novel treatment approach to remove cortical bone and root-end during periapical surgery with the help of Cone-Beam Computed Tomography (CBCT), Computer Aided Design (CAD) and three-dimensional (3D) printing technology. CASE PRESENTATION: A 37-year-old female patient presented with a large periapical lesion of left maxillary lateral incisor and canine was referred for microsurgical endodontic surgery. The data acquired from a preoperative diagnostic CBCT scan and an intra-oral scan was uploaded into surgical planning software and matched. A template that could be used to locate root-ends and lesion areas was virtually designed based on the data and was fabricated using a 3D printer. With the guidance of the template, the overlying cortical bone and root-end were precisely removed by utilizing a trephine with an external diameter of 4.0 mm. The patient was clinically asymptomatic at a six-month follow-up review. One year after the surgery, the lesion was healing well and no periapical radiolucency was observed on radiographic examination. CONCLUSIONS: The digitally designed directional template worked in all aspects to facilitate the periapical surgery as anticipated. The root-ends were accurately located and resected. The surgical procedure was simplified, and the treatment efficiency was improved. This technique minimized the damage and reduced iatrogenic injury.

Direct resin composite restoration of maxillary central incisors using a 3D-printed template: two clinical cases.

BACKGROUND: Three-dimensional (3D) printing technology is used widely in dentistry for applications including implant surgery, oral and maxillofacial surgery, orthognathic surgery, endodontics and prosthodontics. Using a 3D-printed template makes performing the repair procedure faster and more convenient. The aesthetic restoration of anterior teeth can recover facial beauty, enhance speaking and chewing functions and improve the quality of life of the patient. CASE PRESENTATION: This article describes two kinds of clinical cases including fractured teeth and dental caries. In both, a 3D-printed template was used for direct resin composite restoration of maxillary central incisors. A 3D-printed template was built using the following 3-step process: data acquisition was conducted via intra-oral scanning, virtual modeling was performed using an imaging process, and manufacturing was performed using a 3D printer. Aesthetically restoring the maxillary incisors with the assistance of the 3D-printed template achieved the anticipated results, and the patients were very satisfied with the effect. CONCLUSIONS: The direct resin composite restoration of maxillary central incisors using a 3D-printed template represents a rapid, convenient, aesthetic and functional option for treating maxillary central incisors. A 3D-printed template is therefore an acceptable and reliable alternative to traditional direct composite restoration of maxillary central incisors including fractured teeth and dental caries.

The relationship between vitamin D receptor gene polymorphism and deciduous tooth decay in Chinese children.

BACKGROUND: In the present study, we explored the link between vitamin D receptor (VDR) BsmI, TaqI, ApaI and FokI gene polymorphisms with deciduous tooth decay in Chinese children. METHODS: Our study included 380 Chinese children aged 4-7 years, whose DNA sample was collected from the buccal mucosa. VDR gene polymorphisms was determined by PCR-RFLP. RESULTS: The adjusted logistic regression analysis demonstrated that BsmI containing the Bb genotype was linked with the increased risk of deciduous tooth decay (OR = 1.856, 95% CI = [1.184, 2.908], p = 0.007). However, VDR polymorphisms ApaI, TaqI and FokI were not associated with deciduous tooth decay (ApaI: OR = 0.839, 95% CI = [0.614, 1.145], p = 0.268; TaqI: OR = 1.150, 95% CI = [0.495, 2.672], p = 0.744; FokI: OR = 0.856, 95% CI = [0.616, 1.191], p = 0.356). CONCLUSIONS: Our results showed that VDR BsmI polymorphism was associated with the risk of deciduous tooth decay in Chinese children aged 4-7 years. However, the specific mechanism remains to further verify through experiment.

Influence of thermocycling on shear bond strength of glass ionomer cement to Er:YAG laser-prepared enamel.

PURPOSE: To evaluate the long-term influence of the shear bond strength (SBS) on glass-ionomer cement (GIC) to Er:YAG-irradiated and bur-prepared enamel. MATERIALS AND METHODS: One hundred and ninety human premolar and molars were selected and the crowns were sectioned. Samples were divided into five groups, according to surface treatments: bur preparation (B); bur preparation, etching with 37% phosphoric acid (BA); laser preparation (L); laser preparation, etching with 37% phosphoric acid (LA); laser preparation, twice irradiating with laser at low (150 mJ, 10 Hz; water spray 10 ml/min) (LL). Samples were subdivided according to the number of thermo-cycles (TCs)-500 TCs, 1,000 TCs, 3,000 TCs, and 5,000 TCs. The SBS between GIC and enamel was measured using a universal testing machine; failure patterns were analyzed with stereomicroscope. The enamel surfaces and the patterns of the junction between GIC and enamel were observed by scanning electronic microscopy (SEM). RESULTS: The SBS of L group was higher than that for the B group (P < 0.05). The failure mode analysis demonstrated a cohesive failure within the cement in BA and LA groups, but the SBS of LA group was higher than that for the BA group (P < 0.05). LL had a similar effect on SBS compared with LA. Thirty-seven percent phosphoric acid had greatly increased SBS of GIC to enamel (P < 0.05). The SBS was significantly affected by thermocycling (TC) (P < 0.05). CONCLUSION: Our results showed that Er:YAG irradiated significantly increased the SBS on GIC to enamel than bur-prepared enamel. In addition, 37% phosphoric acid pretreated also significantly increased the SBS on GIC to enamel. However, the results of these in vitro tests were limited, and extrapolation to the clinical situation was difficult. Thus, further studies were needed on this subject to simulate the highly complex and dynamic environment in the analysis. Lasers Surg. Med. 48:978-984, 2016. © 2015 Wiley Periodicals, Inc.

Effect of pretreatment on Er:YAG laser-irradiated dentin.

Erbium:yttrium-aluminum-garnet (Er:YAG) laser preparation of tooth cavities for restoration is an increasingly popular method, but its compatibility with existing composite material bonding protocols has not been fully defined. This study evaluated the effect of laser and etchant pretreatments on the performance of one-bottle self-etch adhesives in Er:YAG laser-prepared dentin. Eight groups of 20 extracted teeth were established to investigate bonding in tested dentin disks. Various combinations of laser preparation (with/without), pretreatment (none/acid-etch/low-fluence Er:YAG irradiation), and self-etching adhesive (G-Bond Plus or Xeno V) were tested. Samples were then restored with composite resin and subjected to a tensile bond strength (TBS) test. We also performed scanning electron microscopy (SEM) on dentin disks from some of these groups before and after adhesive application to evaluate their microscopic morphological appearance. Statistical analysis (Dunnett T3 test coupled with the general linear model at 5% significance level) revealed that the laser preparation of dentin did not impact on TBS (p = 0.914), whereas pretreatment with either phosphoric acid (p < 0.0001) or low-fluence Er:YAG laser irradiation (p < 0.0001) significantly increased TBS, although there was no difference between them in their respective elevation of TBS. SEM analysis demonstrated that both acid and laser pretreatments reduced irregularities and produced a more homogeneous surface. Er:YAG laser preparation does not compromise the efficacy of one-step self-etch dentin adhesives, and pretreatment with phosphoric acid or low-fluence Er:YAG laser can significantly increase the TBS of adhesion to this irradiated dentin.

Advances in the relationship between periodontopathogens and respiratory diseases (Review).

Periodontitis is a common chronic inflammatory and destructive disease in the mouth and is considered to be associated with systemic diseases. Accumulating evidence has suggested that periodontitis is a risk factor for pulmonary diseases such as pneumonia, chronic obstructive pulmonary disease (COPD), asthma, coronavirus disease 2019 (COVID­19) and lung cancer. The presence of common periodontal pathogens has been detected in samples from a variety of pulmonary diseases. Periodontal pathogens can be involved in lung diseases by promoting the adhesion and invasion of respiratory pathogens, regulating the apoptosis of respiratory epithelium and inducing overexpression of mucin and disrupting the balance of immune systemin respiratory epithelium cells. Additionally, measures to control plaque and maintain the health of periodontal tissue can decrease the incidence of respiratory adverse events. This evidence suggests a close association between periodontitis and pulmonary diseases. The present study aimed to review the clinical association between periodontitis and pneumonia, COPD, asthma, COVID­19 and lung cancer, and propose a possible mechanism and potential role of periodontal pathogens in linking periodontal disease and lung disease. This could provide a direction for further research on the association between periodontitis and lung disease and provide novel ideas for the clinical diagnosis and treatment management of these two diseases.

Comparison of tensile bond strengths of four one-bottle self-etching adhesive systems with Er:YAG laser-irradiated dentin.

This study aimed to investigate the interaction of current one-bottle self-etching adhesives and Er:YAG laser with dentin using a tensile bond strength (TBS) test and scanning electron microscopy (SEM) in vitro. Two hundred and thirteen dentin discs were randomly distributed to the Control Group using bur cutting and to the Laser Group using an Er:YAG laser (200 mJ, VSP, 20 Hz). The following adhesives were investigated: one two-step total-etch adhesive [Prime & Bond NT (Dentsply)] and four one-step self-etch adhesives [G-Bond plus (GC), XENO V (Dentsply), iBond Self Etch (Heraeus) and Adper Easy One (3 M ESPE)]. Samples were restored with composite resin, and after 24-hour storage in distilled water, subjected to the TBS test. For morphological analysis, 12 dentin specimens were prepared for SEM. No significant differences were found between the control group and laser group (p = 0.899); dentin subjected to Prime & Bond NT, XENOV and Adper Easy One produced higher TBS. In conclusion, this study indicates that Er:YAG laser-prepared dentin can perform as well as bur on TBS, and some of the one-step one-bottle adhesives are comparable to the total-etch adhesives in TBS on dentin.

Advances in the Role of Sodium Hypochlorite Irrigant in Chemical Preparation of Root Canal Treatment.

Irrigation of root canal system is of great significance to the success of endodontic treatment, where sodium hypochlorite (NaOCl) is the most widely used irrigant in chemical preparation. NaOCl functions by eliminating bacterial biofilms and dissolving organic tissue, which may vary according to several factors such as the microbiology of root canal infection and the concentration of the irrigant. It has been proposed that the effectiveness of NaOCl could be enhanced via several methods, including heating the irrigant, applying in conjunction with certain reagents, or activating by agitation techniques. Despite its antibacterial and tissue-dissolving capacities, NaOCl should be used with caution to avoid detrimental effect due to its cytotoxicity and negative effect on dentin properties. In this narrative review, we discussed the factors that affect the properties of NaOCl, the methods to improve its efficacy, and the side effects that might occur in clinical practice.

Biomechanical properties of different endocrown designs on endodontically treated teeth.

OBJECTIVE: To compare the biomechanical properties of different endocrown designs on endodontically treated teeth with an extensive defect in the mesial wall using a three-dimensional finite element method (3D FEM). METHODS: Four finite element analysis models were designed and built up based on different endocrown configurations in a mandibular molar. One model was designed as a butt joint preparation with 2 mm occlusal thickness(control), the other three models were butt joint designs with different distances between the bottom of the mesial wall preparation and the cemento-enamel junction (CEJ): 2 mm, 1 mm and 0 mm respectively. A vertical load parallel with the longitudinal axis of the tooth and an oblique load with a 45°angle to the longitudinal axis were applied to the occlusal surfaces. The maximum Von Misses (VM) stresses and stress distribution patterns were calculated and compared. Weibull risk-of-rupture analysis was used to analyze the survival probability of the restorations and tooth in the different models. RESULTS: For the restoration, the model with a mesial wall destruction at the level of CEJ showed much higher risk of failure than other models. Overall, none of the four models showed failure. Under oblique loading, VM stress in the cement layer of the models with a mesial wall defect was higher than in the control model. In the dentin, the highest VM stresses were found in the peri-cervical dentin. Under the oblique loading, the model with the mesial wall destruction at the level of CEJ restored by endocrown showed the highest risk of failure. CONCLUSION: Under the oblique loading, with the increase of the simulated defect in the mesial wall, the peak VM stress values in the cement layer increased accordingly. In the model with a mesial wall defect up to the level of CEJ risk of failure was highest in the cervical dentin.

Multifunctional Lithium-Doped Mesoporous Nanoparticles for Effective Dentin Regeneration in vivo.

Introduction: Effective infection control without irritating the pulp tissue is the key to successful vital pulp therapy. Developing a novel antibacterial biomaterial that promotes dentin regeneration for pulp capping is thus a promising strategy for enhancing vital pulp therapy. Methods: Lithium-doped mesoporous nanoparticles (Li-MNPs) were synthesized using an alkali-catalyzed sol-gel method. The particle size, elemental distribution, surface morphology, pore structure, and ion release from Li-MNPs were measured. Human dental pulp stem cells (hDPSCs) and Streptococcus mutans (S. mutans) were used to evaluate the biological effects of Li-MNPs. In addition, a dental pulp exposure mouse model was used to evaluate the regenerative effects of Li-MNPs. Results: Li-MNPs had a larger surface area (221.18 m2/g), a larger pore volume (0.25 cm3/g), and a smaller particle size (520.92 ± 35.21 nm) than MNPs. The in vitro investigation demonstrated that Li-MNPs greatly enhanced the biomineralization and odontogenic differentiation of hDPSCs through the Wnt/ß-catenin signaling pathway. Li-MNPs showed a strong antibacterial effect on S. mutans. As expected, Li-MNPs significantly promoted dentin regeneration in situ and in vivo. Conclusion: Li-MNPs promoted dentin regeneration and inhibited S. mutans growth, implying a possible application as a pulp capping agent in vital pulp therapy.

3D-printed gelatin/sodium alginate/58S bioactive glass scaffolds promote osteogenesis in vitro and in vivo.

Three-dimensional (3D)-printed scaffolds are a new strategy to fabricate biomaterials for treating bone defects. Here, using a 3D-printing technique, we fabricated scaffolds consisting of gelatin (Gel), sodium alginate (SA), and 58S bioactive glass (58S BG). To evaluate mechanical properties and biocompatibility of Gel/SA/58S BG scaffolds, the degradation test, compressive strength test, and cytotoxicity test were performed. The effect of the scaffolds on cell proliferation in vitro was determined by 4',6-diamidino-2-phenylindole (DAPI) staining. To evaluate osteoinductive properties, rBMSCs were cultured on the scaffolds for 7, 14, and 21 days and the expression of osteogenesis-related genes was analyzed using qRT-PCR. To examine the bone healing properties of Gel/SA/58S BG scaffolds in vivo, we used a rat mandibular critical-size defect bone model. The scaffolds were implanted into the defect area of rat mandible and bone regeneration and new tissue formation were assessed using microcomputed tomography (microCT) and hematoxylin and eosin (H&E) staining. The results showed that Gel/SA/58S BG scaffolds had appropriate mechanical strength as a filling material for bone defects. Furthermore, the scaffolds could be compressed within certain limits and then could recover their shape. The extract of the Gel/SA/58S BG scaffold showed no cytotoxicity. In vitro, the expression levels of Bmp2, Runx2, and OCN were increased in rBMSCs cultured on the scaffolds. In vivo, microCT and H&E staining demonstrated that scaffolds induced the formation of new bone at the mandibular defect area. These results indicated that Gel/SA/58S BG scaffolds have excellent mechanical characteristics, biocompatibility, and osteoinductive properties, suggesting that it could be a promising biomaterial for the repair of bone defects.