Effects of probiotics on the oral health of patients undergoing orthodontic treatment: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: The effect of probiotics on oral health maintenance in orthodontic patients remains controversial. The aim of the study is to systematically review and assess the effects of probiotics on the oral health and microbiome of patients undergoing orthodontic treatment. SEARCH METHODS AND SELECTION CRITERIA: Databases including PubMed, Web of Science, Cochrane Library, ClinicalTrials.gov, and ProQuest Dissertations & Theses Global databases were searched from their inception until June 2022. Randomised controlled trials that assessed the effects of probiotics on clinical and microbial outcomes in patients undergoing orthodontic treatment were included. DATA COLLECTION AND ANALYSIS: Data screening and collection were performed, and the risk of bias (RoB) was assessed using the Cochrane RoB 2 tool. The meta-analysis evaluated the effects of probiotics on Streptococcus mutans (S. mutans) and Lactobacillus counts. The quality of the evidence from the meta-analyses was assessed with Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: A total of 405 records were identified, of which 15 studies were included in the qualitative synthesis and 4 in the meta-analysis. The patients in all the included studies were treated with fixed orthodontic appliances. Results regarding clinical outcomes were controversial; four out of five studies reported no significant changes in plaque in the probiotic group (P > .05), and two out of three studies reported no significant changes in the gingival index (P > .05). Regarding microbial outcomes, the meta-analysis results revealed that probiotics significantly increased the likelihood of reducing the abundance of S. mutans to below 105 CFU/ml (risk ratio: 2.05 [1.54, 2.72], P < .001) and reduced the likelihood of increasing the abundance of S. mutans to beyond 106 CFU/ml (risk ratio: 0.48 [0.28, 0.83], P = .009). However, the quality of evidence according to the GRADE was moderate. CONCLUSIONS AND IMPLICATIONS: There is insufficient evidence to determine the clinical benefits of probiotics as a supplement for the oral health of patients undergoing orthodontic treatment. However, probiotics may have benefits in reducing the salivary S. mutans counts in orthodontic patients. REGISTRATION: PROSPERO (CRD42022366650).

[Safety evaluation of Tibetan medicine Qishiwei Zhenzhu Pills based on serum pharmacochemistry and network pharmacology].

To explore the mechanism of the active ingredients of Qishiwei Zhenzhu Pills in inhibiting the hepatorenal toxicity of the zogta component based on serum pharmacochemistry and network pharmacology, thereby providing references for the clinical safety application of Qishiwei Zhenzhu Pills. The small molecular compounds in the serum containing Qishiwei Zhenzhu Pills of mice were identified by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS). Then, by comprehensively using Traditional Chinese Medicines Systems Pharmacology(TCMSP), High-throughput Experiment-and Reference-guided Database(HERB), PubChem, GeneCards, SuperPred, and other databases, the active compounds in the serum containing Qishiwei Zhenzhu Pills were retrieved and their action targets were predicted. The predicted targets were compared with the targets of liver and kidney injury related to mercury toxicity retrieved from the database, and the action targets of Qishiwei Zhenzhu Pills to inhibit the potential mercury toxicity of zogta were screened out. Cytoscape was used to construct the active ingredient in Qishiwei Zhenzhu Pills-containing serum-action target network, and STRING database was used to construct the protein-protein interaction(PPI) network of intersection targets. The Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analyses were carried out on the target genes by the DAVID database. The active ingredient-target-pathway network was constructed, and the key ingredients and targets were screened out for molecular docking verification. The results showed that 44 active compounds were identified from the serum containing Qishiwei Zhenzhu Pills, including 13 possible prototype drug ingredients, and 70 potential targets for mercury toxicity in liver and kidney were identified. Through PPI network topology analysis, 12 key target genes(HSP90AA1, MAPK3, STAT3, EGFR, MAPK1, APP, MMP9, NOS3, PRKCA, TLR4, PTGS2, and PARP1) and 6 subnetworks were obtained. Through GO and KEGG analysis of 4 subnetworks containing key target genes, the interaction network diagram of active ingredient-action target-key pathway was constructed and verified by molecular docking. It was found that taurodeoxycholic acid, N-acetyl-L-leucine, D-pantothenic acid hemicalcium, and other active ingredients may regulate biological functions and pathways related to metabolism, immunity, inflammation, and oxidative stress by acting on major targets such as MAPK1, STAT3, and TLR4, so as to inhibit the potential mercury toxicity of zogta in Qishiwei Zhenzhu Pills. In conclusion, the active ingredients of Qishiwei Zhenzhu Pills may have a certain detoxification effect, thus inhibiting the potential mercury toxicity of zogta and playing a role of reducing toxicity and enhancing effect.

Meta-analysis Flavonoids from traditional Chinese herbs for diabetes in rats: a network Meta-analysi.

OBJECTIVE: In this Meta-analysis, we evaluated the hypoglycemic effect of 5 flavonoids found in traditional Chinese herbs (naringenin, kaempferol, puerarin, baicalein, and luteolin) on diabetic rats. METHODS: Four databases including PubMed, Web of Science, Embase, and Cochrane Library, were searched from inception to May 2020. Only studies using diabetes model rats were included in the analysis. Blood glucose data from the last measurement were collected and analyzed. Pair-wise Meta-analyses were conducted using STATA v14.0 software and a Meta-analysis was conducted using STATA v14.0, ADDIS v1.16.6, and R v3.6.1. The quality of included studies was assessed with the SYRCLE risk of bias tool for animal studies, and publication bias was evaluated with a comparisonadjusted funnel plot. RESULTS: A total of 33 studies were included in the analysis, in which all 5 flavonoids showed a beneficial effect on blood glucose level of diabetic rats were included in the final analysis. The standardized mean differences (95% confidence intervals) were -4.92 (-6.67, -3.17) fornaringenin, -12 (-18.74, -5.27) for kaempferol, -2.52 (-3.77, -1.26) for puerarin, -3.04 (-5.75, -0.34) for baicalein, and -1.94 (-2.95, -0.92) for luteolin. The network Meta-analysis showed no statistically significant differences between the effect sizes of the flavonoids. CONCLUSION: The results of the Meta-analysis showed that naringenin, kaempferol, puerarin, baicalein, and luteolin all have clear hypoglycemic effects in rat diabetes models, highlighting their therapeutic potential for preventing and treating diabetes mellitus in clinical practice.

Exploring the role of Tibetan medicinal formula Qishiwei Zhenzhu Pills (Ranasampel) against diabetes mellitus-linked cognitive impairment of db/db mice through serum pharmacochemistry and microarray data analysis.

Background: Diabetes cognitive impairment (DCI) is a common diabetic central nervous system disorder that severely affects the quality of life of patients. Qishiwei Zhenzhu Pills (Ranasampel) is a valuable Tibetan medicine formula with the ability to improve cerebral blood vessels, protect nerves and improve learning and memory, which has also been widely verified in clinical and basic research. Currently, the prevention and treatment of DCI are still in the exploratory research stage, and the use of Ranasampel will provide new ideas and insights for its treatment. Objective: This study is to explore the absorbed components in serum derived from Ranasampel using serum pharmacochemistry, then identify the potential mechanism of Ranasampel for the treatment of DCI through bioinformatics and microarray data validation. Methods: The UPLC-Q-Exactive MS/MS-based serum pharmacochemistry method was conducted to identify the main active components in serum containing Ranasampel. Then, these components were used to predict the possible biological targets of Ranasampel and explore the potential targets in treating DCI by overlapping with differentially expressed genes (DEGs) screened from Gene Expression Omnibus datasets. Afterward, the protein-protein interaction network, enrichment analyses, hub gene identification, and co-expression analysis were used to study the potential mechanism of Ranasampel. Particularly, the hub genes and co-expression transcription factors were further validated using hippocampal expression profiles of db/db mice treated with Ranasampel, while the Morris water-maze test and H&E staining were used to assess the spatial learning and memory behaviors and histopathological changes. Results: Totally, 40 compounds derived from Ranasampel had been identified by serum sample analysis, and 477 genes related to these identified compounds in Ranasampel, 110 overlapping genes were collected by the intersection of Ranasampel target genes and DEGs. Further comprehensive analysis and verification emphasized that the mechanism of Ranasampel treatment of DCI may be related to the improvement of learning and memory function as well as insulin resistance, hyperglycemia-induced neuronal damage, and neuroinflammation. Conclusion: This study provided useful strategies to explore the potential material basis for compound prescriptions such as Ranasampel. These hub genes and common pathways also provided new ideas for further study of therapeutic targets of DCI and the pharmacological mechanism of Ranasampel.

Network Pharmacology Analysis of ZiShenWan for Diabetic Nephropathy and Experimental Verification of Its Anti-Inflammatory Mechanism.

BACKGROUND: Diabetic nephropathy (DN) is the leading cause of end-stage renal disease (ESRD). The inflammatory response plays a critical role in DN. ZiShenWan (ZSW) is a classical Chinese medicinal formula with remarkable clinical therapeutic effects on DN, but its pharmacological action mechanisms remain unclear. AIM: In this study, a network pharmacology approach was applied to investigate the pharmacological mechanisms of ZSW in DN therapy. Based on the results of network analysis, the core targets and signaling pathways related to anti-inflammatory effect were verified via experiments in vivo. METHODS: The candidate chemical ingredients of ZSW as well as its putative targets and known therapeutic targets of DN were acquired from appropriate databases. The "herb-ingredient-target" network for ZSW in DN treatment was established. The protein-protein interaction (PPI) network of potential targets was constructed to screen the core targets. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. In addition to biochemical and pathological indicators, the core targets and signaling pathways associated with inflammation were partially validated in db/db mice at molecular level. RESULTS: A total of 56 active ingredients in ZSW and 166 DN-related targets were selected from databases. A high proportion of core targets and top signaling pathways participate in inflammation. ZSW markedly alleviated renal injuries pathologically and regulated related biomarkers. In particular, ZSW significantly inhibited the exaggerated release of inflammatory cytokines such as interleukin (IL)-1ß, IL-6, tumor necrosis factor receptor (TNF)-ɑ, and monocyte chemotactic protein (MCP)-1 as well as regulating p38 mitogen-activated protein kinases (MAPK) and phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt) signaling pathways in db/db mice. CONCLUSION: This study first comprehensively investigated the active ingredients, potential targets, and molecular mechanism of ZSW as a therapy for DN. ZSW achieved renoprotective effects in DN via regulation of multiple targets and signaling pathways, especially by alleviating inflammation. Results indicate that ZSW is a promising multi-target therapeutic approach for DN treatment.

A Chinese Patent Medicine JiaYanKangTai Alleviates Inflammatory Lesions of Experimental Autoimmune Thyroiditis by Regulating Interleukin-17 Signaling.

Objective: This study was aimed to investigate the effects of JiaYanKangTai (JYKT) on regulating interleukin-17 (IL-17) signaling in rats with autoimmune thyroiditis. Methods: Lewis rats were administrated with JYKT for eight weeks after a seven-week subcutaneous injection of thyroglobulin with adjuvant and feeding iodine water. Ultrasonography was performed and total volume of thyroid was calculated. The expressions of autoantibodies and hormones were detected. Morphological changes of thyroid were observed. Metabolomics profile and metabolic network analysis were conducted. IL-17 signaling was detected by polymerase chain reaction and immunohistochemistry separately. Results: JYKT reduced the mean volumes of thyroid, decreased both levels of TPOAb and TGAb, and alleviated lymphocytic infiltration of the thyroid. Metabolic network analysis of metabolomics proved IL-17 signaling pathway as a critical pathway in JYKT administration for autoimmune thyroiditis. JYKT downregulated expressions of IL-17A, TRAF6, p-ERK1/2 and TNF-α. Conclusion: JYKT alleviated inflammatory lesions of experimental autoimmune thyroiditis by regulating IL-17 signaling.

Therapeutic Potential of Centella asiatica and Its Triterpenes: A Review.

Centella asiatica (also known as Centella asiatica (L.) Urb. or Gotu kola) is a traditional Chinese medicine with extensive medicinal value, which is commonly used in Southeast Asian countries. This study aimed to summarize the effects of C. asiatica and its main components on neurological diseases, endocrine diseases, skin diseases, cardiovascular diseases, gastrointestinal diseases, immune diseases, and gynecological diseases, as well as potential molecular mechanisms, to study the pathological mechanism of these diseases based on the changes at the molecular level. The results showed that C. asiatica and its triterpenoids had extensive beneficial effects on neurological and skin diseases, which were confirmed through clinical studies. They exhibited anti-inflammatory, anti-oxidative stress, anti-apoptotic effects, and improvement in mitochondrial function. However, further clinical studies are urgently required due to the low level of evidence and lack of patients.

Low-level laser-aided orthodontic treatment of periodontally compromised patients: a randomised controlled trial.

Low-level laser irradiation (LLLI) shows effects in orthodontic pain relief and periodontal inflammation control. The aim of this article is to investigate the analgesic and inflammation-modulatory effects of low-level laser irradiation among orthodontic patients with compromised periodontium. A randomised controlled trial with split-mouth design was conducted in 27 adults with treated and controlled chronic periodontitis over 6 months. One side of the dental arch underwent repeated treatment under a 940-nm diode laser (EZlase; Biolase Technology Inc.) with a beam size of 2.8 cm2 for 60 seconds at 8.6 J/cm2, whilst the other side received pseudo-laser treatment. Laser irradiation was applied repeatedly for 8 times during the first 6 weeks after bracket bonding and monthly thereafter until the end of orthodontic treatment. Subjective pain (assessed by visual analogue scale in pain diary and by chairside archwire activation), periodontal status (assessed by periodontal clinical parameters), cytokines in gingival crevicular fluid (interleukin 1ß, prostaglandin E2, substance P) and periodontopathic bacteria (Porphyromonas gingivalis and Treponema denticola) in supragingival plaque were assessed. The intensity of pain was lower on the laser-irradiated side at multiple follow-up visits (P < 0.05). The pain subsided 1 day earlier on the laser side, with a lower peak value during the first week after initial archwire placement (P < 0.05). The laser side exhibited a smaller reduction in bite force during the first month (mean difference = 3.17, 95% CI: 2.36-3.98, P < 0.05 at 1-week interval; mean difference = 3.09, 95% CI: 1.87-4.32, P < 0.05 at 1-month interval). A smaller increase was observed in the plaque index scores on the laser side at 1-month (mean difference = 0.19, 95% CI: 0.13-0.24, P < 0.05) and in the gingival index scores at the 3-month follow-up visit (mean difference = 0.18, 95% CI: 0.14-0.21, P < 0.05). Laser irradiation inhibited the elevation of interleukin-1ß, prostaglandin E2 and substance P levels during the first month (P < 0.05). However, no intergroup difference was detected in the bacteria levels. Low-level laser irradiation exhibits benefits in pain relief and inflammation control during the early stage of adjunctive orthodontic treatment in periodontally compromised individuals.

EphrinB2 signaling enhances osteogenic/odontogenic differentiation of human dental pulp stem cells.

OBJECTIVE: To investigate the role of the EphrinB2 signaling pathway in the osteogenesis/odontogenesis of human dental pulp stem cells (DPSCs). DESIGN: The endogenous expression levels of EphrinB2 and its cognate receptors EphB2 and EphB4 in DPSCs were analyzed by qRT-PCR and Western blotting after 7, 14 and 21 days of osteogenic/odontogenic induction culture. Additionally, the phosphorylation of EphrinB2, EphB4 and ERK1/2 proteins at early time-points following osteogenic induction, were also investigated by Western blots. Subsequently, we investigated whether supplementation of recombinant EphrinB2-Fc within the induction milieu can enhance the osteogenic/odontogenic differentiation of DPSCs. RESULTS: Endogenous gene and protein expression levels of EphrinB2, EphB2 and EphB4 were upregulated in induced versus non-induced DPSCs, over 21 days of osteogenic/odontogenic induction. Western blots showed increase in phosphorylated EphrinB2, EphB4 and ERK1/2 proteins at early time-points following osteogenic induction. Preliminary investigation of a concentration range (0, 0.5, 1 and 2 µg/ml) of recombinant EphrinB2-Fc within osteogenic induction media, showed that 0.5 µg/ml was optimal for enhancing the osteogenic/odontogenic differentiation of DPSCs over a culture duration of 14 days. Subsequently, more comprehensive qRT-PCR analysis with 0.5 µg/ml EphrinB2-Fc revealed significant upregulation of several key osteogenic marker genes in treated versus untreated DPSCs after 21 days of osteogenic/odontogenic induction. By 7 days of osteogenic induction, DPSCs treated with 0.5 µg/ml EphrinB2-Fc exhibited significantly more calcium mineralization (Alizarin red S staining) and alkaline phosphatase activity than the untreated control. CONCLUSIONS: EphrinB2 signaling plays a key role in the osteogenic/odontogenic differentiation of DPSCs.

Protective effects of Jiayan Kangtai granules on autoimmune thyroiditis in a rat model by modulating Th17/Treg cell balance.

OBJECTIVE: To investigate the protective effects of Jiayan Kangtai (JYKT) granules, consisting of 9 Chinese herbs, in a rat model of autoimmune thyroiditis (AIT), and the possible underlying mechanism. METHODS: Female Lewis rats (6-8 weeks) were randomly apportioned to 5 groups of 10, including a normal control. AIT was induced in the untreated AIT-model group, and rats treated subsequently with daily low, medium, or high dose JYKT granules. After 12 weeks, plasma levels of thyroid autoantibodies and morphological changes in the thyroid were detected by enzyme-linked immunosorbent assay and histological examination, respectively. The presence of interleukin (IL)-6, IL23p19, and IL-2 in thyroid tissue was assessed by immunohistochemical staining. The percentages of T helper (Th)17 cells and regulatory T cells (Tregs) in the peripheral blood were analyzed by flow cytometry. Relevant levels of cytokines and proteins were examined via bead-based multiplex flow cytometry and ELISA, respectively. Expressions of genes and proteins regulated by Th17 cells and Tregs were shown by real-time PCR and Western blot. RESULTS: Compared to the control, AIT-model rats had higher plasma concentrations of thyroid autoantibodies. The high-dose JYKT rats showed significantly lower levels of thyroid autoantibodies compared with the AIT model group. Rats in the AIT-JYKT groups also had fewer thyroid lesions and less lymphocytic infiltration, a lower percentage of Th17 cells, and a higher percentage of Tregs, compared with the AIT-model. Rats given high-dose JYKT had a significantly lower Th17/Treg ratio compared with the AIT model. Differences in plasma cytokine concentrations and relevant gene and protein expressions in the spleens of JYKT-treated rats and the AIT group suggested an association between JYKT treatment and lower Th17 cell percentage and higher Treg activity. CONCLUSION: JYKT treatment appeared to be protective against AIT in rats, possibly via the regulation of the Th17 cell/Treg imbalance in AIT.

Effect of diode low-level lasers on fibroblasts derived from human periodontal tissue: a systematic review of in vitro studies.

This study aimed to systematically assess the parameter-specific effects of the diode low-level laser on human gingival fibroblasts (HGFs) and human periodontal ligament fibroblasts (HPDLFs). An extensive search was performed in major electronic databases including PubMed (1997), EMBASE (1947) and Web of Science (1956) and supplemented by hand search of reference lists and relevant laser journals for cell culture studies investigating the effect of diode low-level lasers on HGFs and HPDLFs published from January 1995 to December 2015. A total of 21 studies were included after screening 324 independent records, amongst which eight targeted HPDLFs and 13 focussed on HGFs. The diode low-level laser showed positive effects on promoting fibroblast proliferation and osteogenic differentiation and modulating cellular inflammation via changes in gene expression and the release of growth factors, bone-remodelling markers or inflammatory mediators in a parameter-dependent manner. Repeated irradiations with wavelengths in the red and near-infrared range and at an energy density below 16 J/cm(2) elicited favourable responses. However, considerable variations and weaknesses in the study designs and laser protocols limited the interstudy comparison and clinical transition. Current evidence showed that diode low-level lasers with adequate parameters stimulated the proliferation and modulated the inflammation of fibroblasts derived from human periodontal tissue. However, further in vitro studies with better designs and more appropriate study models and laser parameters are anticipated to provide sound evidence for clinical studies and practice.

Effectiveness of Sonic, Ultrasonic, and Photon-Induced Photoacoustic Streaming Activation of NaOCl on Filling Material Removal Following Retreatment in Oval Canal Anatomy.

OBJECTIVE: This study aimed to assess the effectiveness of sonic, ultrasonic and laser [photon-induced photoacoustic streaming (PIPS)] irrigation activation in removing filling remnants from oval root canals after standard canal retreatment procedures with the ProTaper universal rotary retreatment system. METHODS: Twenty-eight maxillary first premolars were instrumented with ProTaper NiTi rotary instruments and obturated with gutta-percha and AH Plus sealer using the continuous wave of condensation technique. After storage at 37°C and 100% humidity for 1 week, the specimens were retreated with the ProTaper universal retreatment system for the removal of filling material. Teeth were then randomly assigned into four groups (n = 7): group 1, positive control; group 2, retreated with sonic irrigation; group 3, retreated with ultrasonic irrigation; and group 4, retreated with laser irradiation. The specimens were scanned using micro-CT before instrumentation, after obturation and mechanical retreatment, and after additional activation procedures. The percentage volume of the filling remnants was measured. Specimens were split longitudinally after micro-CT scan, canal walls were examined using scanning electron microscopy (SEM), and the amount of residual filling material was scored. RESULTS: The filling materials' removal efficacy in the three experimental groups was higher than that of the control group (p < 0.05), whereas filling materials ranging from 1.46 ± 0.30 to 2.21 ± 0.46 mm(3) remained in the canal in all three experimental groups. Additionally, there was a significantly greater reduction in the amount of filling remnants in the PIPS group than in the sonic and ultrasonic groups (both p < 0.05), and significantly greater reduction in the ultrasonic group than the sonic group (p < 0.05). CONCLUSIONS: Activation of NaOCl with PIPS showed significantly better performance than sonic and ultrasonic techniques in removing the filling remnants following mechanical retreatment of oval root canals. The ultrasonic technique also performed better than the sonic technique. However, none of the additional activation procedures was able to completely eliminate the filling remnants.

Comparison of the antibacterial effect and smear layer removal using photon-initiated photoacoustic streaming aided irrigation versus a conventional irrigation in single-rooted canals: an in vitro study.

OBJECTIVE: The Er:YAG laser with photon-induced photoacoustic streaming (PIPS) technique was reported to be effective in root canal disinfection. This study attempted to further investigate the antibacterial efficacy and smear layer removal ability of PIPS in comparison with conventional syringe irrigation in vitro. METHODS: For antibacterial analysis, 48 single-rooted human teeth were prepared and inoculated with Enterococcus faecalis, and then divided into six groups of eight roots each. The colony-forming units (CFUs) per milliliter were determined after infection as the baseline. Then, the teeth were subjected to either PIPS plus 3% sodium hypochlorite (PIPS+NaOCl) or conventional syringe irrigation with 0.9% saline, 3% NaOCl, 17% ethylenediaminetetraacetic acid (EDTA), 0.2% chlorhexidine gluconate (CHX), or 3% NaOCl alternating with 17% EDTA. The reduction of CFUs in the individual group was determined. Additionally, scanning electron microscopy (SEM) examination of the canal walls for E. faecalis colonization was performed. For comparing the smear removal efficacy, another 48 single-rooted teeth, assigned to different groups as mentioned, were irrigated after mechanical instrumentation. The presence of a smear layer at different levels of the root canal was scored by SEM examination. RESULTS: No significant differences were found in CFU reduction. No bacteria could be observed by SEM in the NaOCl, NaOCl+EDTA, and PIPS+NaOCl groups. The scores of smear layer of the NaOCl+EDTA and PIPS+NaOCl groups were significantly lower than those of the other groups in the coronal and middle third of the root canal. None of the methods can effectively remove smear layer in the apical third. CONCLUSIONS: PIPS system supplied with NaOCl and conventional syringe irrigation with NaOCl+EDTA are comparable in their ability to remove E. faecalis and smear layer in single-rooted canals.

Effectiveness of photoactivated disinfection (PAD) to kill enterococcus faecalis in planktonic solution and in an infected tooth model.

OBJECTIVE: The aim of this study was to investigate the effectiveness of photoactivated disinfection (PAD) in killing Enterococcus faecalis (EF) in planktonic solution and in an infected tooth model. METHODS: One hundred and thirty-two glass tubes of EF samples with concentration of 10(14) colony forming units (CFU)/mL and photosensitizer were prepared. Sixteen groups were set up and subjected to diode laser, and then received a radiation energy dose ranging from 0.5 to 5.5 J. The bactericidal effect was measured by the mean CFU of viable EF after irradiation. Sixty single-rooted teeth were selected and contaminated with EF, and then given PAD therapy; 5.25% NaOCl irrigation and saline solution were used to disinfect the root canals. Microbial samples were taken before and after disinfection, and after 72 h recovery, and then the CFU were counted. RESULTS: The bactericidal effect increased linearly with the irradiation energy dose in planktonic solution. For the same irradiation energy dose, the bactericidal effect was greater in group receiving 100 mW than in that receiving 50 mW and exposed to doubled irradiation time (p<0.05). No bacterium was detected after irrigation in the NaOCl group in the root canal model, but the recovery of bacteria after 72 h was detected in 11 samples. Bacteria were detected in all the other groups, and PAD was significantly more effective than saline solution in reducing the number of bacterial cells within the root canals (p<0.05). CONCLUSIONS: PAD was shown to have bactericidal effect on EF, and the bactericidal effect increased linearly with the irradiation energy dose and was superior using higher output power. PAD could decrease EF in root canals effectively, but was no more effective than 5.25% NaOCl, and PAD is more effective in planktonic solution than in root canals.

Malocclusions in Xia Dynasty in China.

BACKGROUND: The prevalence of malocclusion in modern population is higher than that in the excavated samples from the ancient times. Presently, the prevalence of juvenile malocclusion in the early stage of permanent teeth is as high as 72.92% in China. This study aimed to observe and evaluate the prevalence and severity of malocclusions in a sample of Xia Dynasty in China, and to compare these findings with the modern Chinese population. METHODS: The material consisted of 38 male and 18 female protohistoric skulls of Xia Dynasty 4000 years ago. Of 86 dental arches, 29 cases had the jaw relationships. Tooth crowding, diastema, individual tooth malposition and malocclusion were studied. RESULTS: Of the samples, 23.3% showed tooth alignment problems including crowding (8.1%), diastema (9.3%), and individual tooth malposition (5.8%). The prevalence of malocclusion was 27.6%, mainly presented as Angle Class I. CONCLUSIONS: It is indicated that over thousands of years from Neolithic Age (6000 - 7000 years ago) to Xia Dynasty (4000 years ago), the prevalence of malocclusion did not change significantly. The prevalence of malocclusion of Xia Dynasty samples was much lower than that of modern population.

Effects of KTP laser irradiation, diode laser, and LED on tooth bleaching: a comparative study.

OBJECTIVE: This in vitro study examines the whitening efficacy of a light-emitting diode (LED), a diode laser, and a KTP laser irradiation in dental bleaching by analyzing the change in color achieved from the treatment, the temperature increase induced in the pulpal cavity, as well as enamel microhardness measurement after treatment. BACKGROUND DATA: Bleaching techniques achieved significant advances with the use of coherent or incoherent radiation sources to activate the bleaching agents. METHODS: A hydrogen peroxide bleaching agent, Hi-Lite, was stimulated with an LED, a 980-nm diode laser at 0.8 W, or a 532-nm KTP laser at 1.0 W for 30 sec on 64 extracted human incisors. During irradiation, the temperature in the pulpal cavity was monitored. The color change was evaluated using the CIE L*a*b* color space measurement system, and Vikers enamel microhardness was tested after treatment. RESULTS: A mean total color difference value (DeltaE*) greater than 5.0 was obtained in each group. KTP-laser-induced bleaching gave a significantly higher DeltaL* (8.35) after treatment (p < 0.01). Neither LED nor the two lasers produced significant differences in the enamel microhardness after treatment (p > 0.01). Mean maximal pulpal temperature rise was 2.95 degrees C for LED, 3.76 degrees C for KTP laser, and 7.72 degrees C for diode laser, respectively. CONCLUSION: The results of this study suggest that KTP laser is effective at providing brighter teeth. According to the conditions used in this study, the LED and KTP laser induced a safer pulpal temperature increase when assisted with Hi-Lite bleaching gel.