IL-21/anti-Tim1/CD40 ligand promotes B10 activity in vitro and alleviates bone loss in experimental periodontitis in vivo.

IL-10-expressing regulatory B cells (B10) play an essential role in immune system balance by suppressing excessive inflammatory responses. In this study, we investigated induction of B 10 cell's IL-10 competency in vitro and its effect on ligature-induced experimental periodontitis in vivo. Spleen B cells were isolated from C57BL/6J mice and cultured for 48h under the following conditions: control, CD40L, IL-21, anti-Tim1, CD40L+IL-21, CD40L+anti-Tim1, CD40L+IL-21+anti-Tim1. Silk ligatures were tied around both maxillary second molars of C57BL/6J mice for two weeks. Optimized combination of CD40L, IL-21 and anti-Tim1 and vehicle were injected into contralateral side of palatal gingiva on days 3, 6 and 9. The palatal gingival tissues and maxillary bone were collected on day 14 to determine expressions of IL-10 and periodontal bone resorption respectively. Our results demonstrated that IL-10 expressions of cultured spleen B cells were significantly increased in the presence of CD40L, IL-21 and anti-Tim1 combination when compared with control groups. Gingival IL-10 mRNA and protein expressions were significantly increased after injection of CD40L, IL-21 and anti-Tim1 combination, when compared to the control side. The gingival RANKL expression and periodontal bone loss were significantly decreased on the combination treatment side, as compared to the control side. These results suggest that combination of IL-21, anti-Tim1 and CD40L treatment induced B10 cell's IL-10 competency in vitro and inhibited periodontal bone loss in ligature-induced experimental periodontitis.

Comparative in vitro study of cementing techniques for implant-supported restorations.

STATEMENT OF PROBLEM: Various techniques are used to cement implant-supported restorations. Excess residual cement is a concern. PURPOSE: The purpose of this in vitro study was to evaluate 3 techniques for cementing implant-supported restorations. MATERIAL AND METHODS: Twelve crowns and implant-abutment complexes (IAC) were cemented with 3 techniques: technique 1, a certain amount of cement evenly placed and excess cement removed with an explorer; technique 2, a smaller amount of cement without removal of excess cement; technique 3, a resin abutment replica used for excess cement removal after using a large amount of cement. Each specimen was treated with each technique 3 times. Precementing discrepancies (predis) and postcementing discrepancies (postdis) between IACs and crowns and the postcementing linear roughness (Ra and Rz) on designated junction areas of each specimen were measured. Tensile strength of the specimens was recorded with a universal testing machine at a crosshead speed of 0.5 mm/min. Repeated measures analysis with mixed models was used for differences among the 3 cementing techniques (α=.05). RESULTS: Compared with techniques 1 and 2, the specimens with technique 3 showed significantly lower mean differences between postdis and predis and Ra and Rz and higher mean tensile strength (P<.05). CONCLUSIONS: The application of a resin abutment replica for the cementation of implant-supported restorations decreased the discrepancy between the restoration and abutment, reduced cement residue, and increased restoration retention.

Effects of pigments on dynamic mechanical properties of a maxillofacial prosthetic elastomer.

STATEMENT OF PROBLEM: Pigmentation and coloration play a key role in fabricating a maxillofacial prosthesis. The addition of pigments and dyes to the maxillofacial material may alter the dynamic mechanical behaviors of the prosthesis, possibly influencing the success of the prosthesis. PURPOSE: The purpose of this study was to investigate the effects of the type and concentration of intrinsic pigments on the dynamic mechanical properties of a commercially available maxillofacial silicone elastomer over a small range of low frequencies. MATERIAL AND METHODS: Ten pigmented mixtures (6 specimens per mixture) were made by using a base silicone elastomer mixed with each intrinsic silicone pigment (Black, Red, Tan, or Yellow) or all the pigments (MixAll) in a designated high or low concentration. The base elastomer without pigment (Unpigment) was prepared as a control. Dynamic mechanical analysis was performed over 5 low frequencies (0.5, 1.0, 1.5, 2.0, and 2.5 Hz) at room temperature. The storage modulus (E'), loss modulus (E″), and loss tangent (tanδ) in compression were determined. Mixed models for repeated measures were used for the comparisons of E', E″, and tanδ among mixtures (α=.05). RESULTS: The means of E', E″, and tanδ of all the pigmented specimens were lower than those of Unpigment. MixAll with high concentration had the lowest values in E' and E″. The means of E' and E″ of Red and Yellow in high concentration were lower than those in low concentration, whereas the means of E' and E″ of Black and Tan in low concentration were significantly lower than those in high concentration; the means of tanδ for all the mixtures in high concentration were significantly lower than those in low concentration. The means of E', E″, and tanδ of all the specimens tested increased as frequency increased from 0.5 to 2.5 Hz (P<.05). CONCLUSIONS: Within the limitations of this study, it was concluded that the addition of intrinsic silicone pigments into a base maxillofacial elastomer significantly influenced dynamic mechanical properties of the maxillofacial silicone elastomer tested over the low frequencies from 0.5 to 2.5 Hz at room temperature. This effect, which was a quick elastic return to its original shape after deformation during pigmentation or coloration, seems desirable to a certain extent in clinical application. The type and concentration of pigment may influence the elastic and viscous portion of the properties of the maxillofacial elastomeric materials tested. Low frequencies (0.5 to 2.5 Hz) affect the dynamic viscoelastic properties of the materials.

Tooth loss, cognitive impairment and chronic cerebral ischemia.

BACKGROUND/PURPOSE: Vascular factor is an important risk factor in the process of cognitive impairment or dementia. Tooth loss could cause impairments of spatial learning and memory in mice, and nitric oxide (NO) and its synthase might be involved in the process. The objectives of this study were to investigate and compare the behavioral impairments between the Wistar rats with tooth loss and those with chronic ischemia and to determine the changes in nitric oxide (NO) and its synthases under those two conditions. MATERIALS AND METHODS: The Morris water maze was used to test the spatial learning and memory abilities in the Wistar rats 8 weeks after the molar extraction procedure and the occlusion of 2 blood vessels to produce cerebral ischemia. The changes in NO and its synthases were evaluated using the Griess assay, Western blotting, and immunohistochemistry. RESULTS: Similar impairments in the spatial learning and memory of Wistar rats were found after tooth loss and the induction of cerebral ischemia. The levels of NO and iNOS in the rat hippocampus increased, and the levels of eNOS decreased. Conclusion: For Wistar rats, the results of cognitive impairments related to tooth loss and those that occur due to chronic cerebral ischemia were statistically not significant and that NO, iNOS and eNOS in the hippocampus are involved in both cases.

Semiconductor laser irradiation improves root canal sealing during routine root canal therapy.

OBJECTIVE: To evaluate the effect of semiconductor laser irradiation on root canal sealing after routine root canal therapy (RCT). METHODS: Sixty freshly extracted single-rooted human teeth were randomly divided into six groups (n = 10). The anatomic crowns were sectioned at the cementoenamel junction and the remaining roots were prepared endodontically with conventional RCT methods. Groups A and B were irradiated with semiconductor laser at 1W for 20 seconds; Groups C and D were ultrasonically rinsed for 60 seconds as positive control groups; Groups E and F without treatment of root canal prior to RCT as negative control groups. Root canal sealing of Groups A, C and E were evaluated by measurements of apical microleakage. The teeth from Groups B, D and F were sectioned, and the micro-structures were examined with scanning electron microscopy (SEM). One way ANOVA and LSD-t test were used for statistical analysis (α = .05). RESULTS: The apical sealing of both the laser irradiated group and the ultrasonic irrigated group were significantly different from the control group (p<0.5). There was no significant difference between the laser irradiated group and the ultrasonic irrigated group (p>0.5). SEM observation showed that most of the dentinal tubules in the laser irradiation group melted, narrowed or closed, while most of the dentinal tubules in the ultrasonic irrigation group were filled with tooth paste. CONCLUSION: The application of semiconductor laser prior to root canal obturation increases the apical sealing of the roots treated.

Perioperative risk factors for postoperative pneumonia after major oral cancer surgery: A retrospective analysis of 331 cases.

OBJECTIVE: Postoperative pneumonia (POP) is common and results in prolonged hospital stays, higher costs, increased morbidity and mortality. However, data on the incidence and risk factors of POP after oral and maxillofacial surgery are rare. This study aims to identify perioperative risk factors for POP after major oral cancer (OC) surgery. METHODS: Perioperative data and patient records of 331 consecutive subjects were analyzed in the period of April 2014 to March 2016. We individually traced each OC patient for a period to discharge from the hospital or 45 days after surgery, whichever occur later. RESULTS: The incidence of POP after major OC surgery with free flap construction or major OC surgery was 11.6% or 4.5%, respectively. Patient-related risk factors for POP were male sex, T stage, N stage, clinical stage and preoperative serum albumin level. Among the investigated procedure-related variables, incision grade, mandibulectomy, free flap reconstruction, tracheotomy, intraoperative blood loss, and the length of the operation were shown to be associated with the development of POP. Postoperative hospital stay was also significantly related to increased incidence of POP. Using a multivariable logistic regression model, we identified male sex, preoperative serum albumin level, operation time and postoperative hospital stay as independent risk factors for POP. CONCLUSION: Several perioperative risk factors can be identified that are associated with POP. At-risk oral cancer patients should be subjected to intensified postoperative pulmonary care.

Interplay between ΔNp63 and miR-138-5p regulates growth, metastasis and stemness of oral squamous cell carcinoma.

TP63 acts as a master regulator in epithelia development and in the progression of various cancers, but its role in oral cancer pathogenesis remains unknown. This study aimed to explore the role of TP63 in the progression of oral squamous cell carcinoma (OSCC). This study shows that ΔNp63, the predominant isoform of TP63, is significantly upregulated in OSCC tissues and cell lines compared with their normal counterparts, and its expression is closely correlated with pathological differentiation, lymph node metastasis and clinical stage in patients with OSCC. The overexpression of ΔNp63 promotes growth, metastasis and stem-like properties in OSCC cells, and ΔNp63 depletion significantly represses OSCC cellular phenotypes in vitro and in vivo. The ΔNp63 isoform transcriptionally suppresses miR-138-5p expression; restoration of miR-138-5p expression partially abolishes the effect of upregulating ΔNp63. This study also demonstrates that miR-138-5p directly targets ΔNp63, resulting in crosstalk with ΔNp63. The correlation between ΔNp63 and miR-138-5p was further validated in OSCC tissues and was found to be significantly associated with the prognosis of patients with OSCC. Therefore, our data reveal that the interplay between ΔNp63 and miR-138-5p promotes OSCC progression by regulating cell growth, metastasis and stemness.

Behavioral impairments and changes of nitric oxide and inducible nitric oxide synthase in the brains of molarless KM mice.

More studies showed that as a common disorder in senior population, loss of teeth could adversely affect human cognitive function, and nitric oxide (NO) might play an important role in the cognitive function. However, the underlying mechanism has not yet been well-established. The objectives of this study are to evaluate behavior changes of KM mice after loss of molars, and levels of NO and inducible nitric oxide synthase (iNOS) in the brain in molarless condition. It is hypothesized that loss of molars of the mice tested results in the cognitive impairments and that the process is mediated by NO in the brain through the signaling pathways. Morris water maze is used to test the behavioral changes after 8 weeks of the surgery. The changes of NO and iNOS are evaluated by using Griess assay, western blot, and immunohistochemistry method. The results show that 8 weeks after loss of molars, the spatial learning and memory of KM mice impair and the levels of NO and iNOS in mice hippocampus increase. These findings suggest that molar extraction is associated with the behavioral impairment, and that the changes of NO and iNOS in the hippocampus may be involved in the behavioral changes in the molarless condition.

Translucency estimation for thick pigmented maxillofacial elastomer.

OBJECTIVES: Human skin is multilayered and inhomogeneous and has a partially translucent structure. Since it is not straightforward to quantify the translucency for human skin as it is for translucent materials at a certain thickness, a laser light-diffusing method was developed to quantitatively approximate translucency of translucent pigmented maxillofacial materials, using a technique that would be applicable to human skin. A developed method of laser light diffusing area (LLDA) and the method of color difference due to edge loss (CDEL) were compared in accuracy of translucency estimations of thick pigmented maxillofacial elastomeric material. METHODS: Thick specimens of 19 different shades of skin-colored maxillofacial elastomer (MFE) were made with a silicone elastomer and four commercially available pigments (tan, red, yellow and black). Translucency parameter (TP) values at a thickness of 1.5mm on ideal black and white backings for each shade based on the CIELAB and CIE2000 color difference formulas were previously calculated, and were predicted by the regressions of TP onto the LLDA and CDEL measurements. RESULTS: Both the LLDA and CDEL methods provided reasonably accurate (adjusted R(2) ≥ 0.919) estimations of TP, and no significant differences were found in the error variances of the regressions. CONCLUSIONS: The laser light diffusing method appears to be highly reliable for the estimation of translucency of maxillofacial elastomer, and the relationship of translucency to LLDA may be used to estimate the apparent translucency of any thick translucent material within the range of translucency studied. The laser light diffusing method as a non-contact and non-destructive method may be applied to quantitatively estimate the translucency of human skin and prosthetic elastomers, and further be incorporated into appearance matching of maxillofacial prosthesis to human skin.

Concentration additivity of coefficients for maxillofacial elastomer pigmented to skin colors.

OBJECTIVE: The purpose of this study is to determine a regression model which performs accurately for predicting Kubelka-Munk (K-M) absorption (K) and scattering (S) coefficients of pigment mixtures in maxillofacial elastomer (MFE). METHODS: Specimens at varying thicknesses of 19 shades of skin-colored MFE were made incorporating tan, red, yellow and black pigments. Using a non-contact 45 degrees/0 degrees spectral reflectance system, reflectance values were obtained and fit by non-linear regression to corrected K-M theory to determine observed K and S values. Predicted values were calculated using: first order linear regression model (M(1)), second order square-factor model (M(2S)), second order interaction-factor model (M(2I)) and complete second order model (M(2C)). Errors between observed and predicted values for each model at each wavelength studied are evaluated. Differences in color and the Translucency Parameter (TP) at a thickness of 1.5 mm based on CIE2000 color difference formula between observed and predicted values were also analyzed using repeated-measures ANOVA (alpha=0.05). RESULTS: M(2C) shows less absolute differences in color and TP (1.5 mm) than those for the M(1) and M(2S) models (P<0.05). SIGNIFICANCE: Within limitations of this study, the complete second order regression model performs accurately in concentration additivity of pigmented maxillofacial elastomer mixture. This regression model is recommended as a viable alternative in the application of colorant formulation based on corrected K-M model for improving appearance match of pigmented maxillofacial prosthesis to human skin.

Interfacial corrections of maxillofacial elastomers for Kubelka-Munk theory using non-contact measurements.

OBJECTIVE: Reflectance measurements using a 45 degrees/0 degrees non-contact measuring system provide accurate data for translucent materials, yet the interfacial reflection corrections (IRCs) for Kubelka-Munk theory have not been evaluated using this system. The objective is to determine which IRC method for Kubelka-Munk theory (K-MT) models the spectral reflectance of pigmented maxillofacial elastomer (MFE) with least error. METHOD: Samples at varying thicknesses of each of 19 shades of skin-colored maxillofacial elastomer were measured using this system on each of three backings. Reflectance values within the visible wavelength range for each shade were fit by non-linear regression to K-MT using different IRC methods: no IRC correction (No), IRC for opaque materials (Op) and IRC for translucent materials (Tr). Errors associated with each method were analyzed using repeated-measures ANOVA and a Bonferroni-corrected t-test. RESULTS: Average error mean square values over all wavelengths were 0.00038 for K-MT with no IRC, 0.00023 with Op IRC, and 0.00015 with Tr IRC. The No method gave a statistically higher error than either the Op or Tr method at all analyzed wavelengths, and the Tr gave a lower error than the OP at all analyzed wavelengths between 450 and 600 nm. The predicted CIELAB values of all the shades tested fell into the range of human skin color space. SIGNIFICANCE: Corrected Kubelka-Munk theory with the IRC for translucent materials proposed by Richmond provides higher accuracy on maxillofacial elastomer over the more important visible wavelengths. Color and translucency of maxillofacial elastomer can be predicted using corrected K-M theory.