A Retrospective Cohort Study of the Cumulative Survival Rate of Obturator Prostheses for Marsupialization.

PURPOSE: After marsupialization of benign tumors and jawbone cysts, insertion of an obturator prosthesis maintains the surgical opening and improves hygiene. To date, there have been no reports clarifying the relationship between the obturator design and treatment outcomes. The purpose of this study was to examine the survival rate of three types of obturator, and to investigate the factors that expedite the removal of the obturator. MATERIALS AND METHODS: The subject group comprised 100 patients who had an obturator inserted after marsupialization at Kagoshima University Hospital between May 31, 2012 and March 31, 2015; 73 patients with lesions in the mandible were eligible. Three types of mandibular obturator were designed and inserted, considering the teeth missing, the anteroposterior position of the lesion, and the buccolingual direction of marsupialization. The endpoint of this study was defined as the removal of the obturator. The analyzed predictor values for the endpoint were age, gender, remaining teeth, nature of primary disease, anteroposterior location of primary disease, buccolingual direction of marsupialization, type of obturator, and dates of insertion and removal. RESULTS: No significant differences were found in the cumulative survival rate among the three types of obturator. Early obturator removal was more frequent in patients with cysts, anterior lesions, and/or marsupialization from the occlusal direction CONCLUSIONS: Because obturator design had minimal effect on the ability of the appliance to maintain the surgical opening, it is preferable to use the least invasive design. Our findings also suggest that the follow-up examination should account for the type of primary disease, the anteroposterior location of the lesion, and the buccolingual direction of marsupialization.

Impact of Types of Moisturizer and Humidity on the Residual Weight and Viscosity of Liquid and Gel Oral Moisturizers.

PURPOSE: Oral moisturizers need to be selected based on their material properties. The purpose of this study was to investigate the effects of moisturizer type and humidity on the residual weight and viscosity of oral moisturizers. MATERIALS AND METHODS: The weight and viscosity of 17 oral moisturizers (7 liquid and 10 gel) at baseline and after 8 hours were measured using an incubator maintained at 37°C at either 85% or 40% relative humidity (RH). The rate of change in weight (RCW) and the rate of change in viscosity (RCV) were calculated. Data were analyzed with two-way analysis of variance (ANOVA) and Scheffe's test to evaluate the effect of the type of moisturizer (liquid or gel) and humidity (85% or 40% RH) on RCW and RCV. Pearson's correlation coefficient was used to evaluate the relationship between RCW and RCV. RESULTS: Two-way ANOVA results indicated that the type of moisturizer and RH had a significant effect on RCW and RCV (p < 0.05); however, the interaction between them was not significant. The results of multiple comparisons showed that gel moisturizers had a significantly lower RCW and higher RCV than liquid moisturizers (p < 0.05). The RCW and RCV at 40% RH were significantly higher than those at 85% RH (p < 0.05). There was no correlation between RCW and RCV in the liquid moisturizer group, but a significant negative correlation was found in the gel moisturizer group (pp = 0.01). CONCLUSION: Because viscosity of gel moisturizers increases as weight decreases, selecting gel moisturizers with a minimal change in weight and viscosity would be preferable in the case of a long-time application and severe dry mouth.

Different hydration states and passive tumor targeting ability of polyethylene glycol-modified dendrimers with high and low PEG density.

It has been reported that the amount of intermediate water, defined as water molecules loosely bound to a material, is a useful index of the material's bio-inert properties. Polyethylene glycol (PEG) is a well-known biocompatible polymer with a large amount of intermediate water. Many researchers have showed that PEGylated nanoparticles are passively accumulated in tumor tissues owing to their enhanced permeability and retention (EPR) effects. Dendrimers are regularly branched polymers with highly controllable size and structure, which can be exploited as potent drug carriers. In this study, we investigated the tripartite relationship among the PEG density, the hydration state, and the passive tumor targeting property, using PEGylated dendrimers. The fully PEGylated dendrimer, PEG64-den, showed similar hydration behavior to PEG and a passive tumor targeting property. In contrast, the hydration state of the partly PEGylated dendrimer, PEG5-den, was different from that of PEG64-den, and the passive tumor targeting property was not observed. This is the first report to show the hydration state of a drug carrier as well as discuss a relationship between the hydration state and biodistribution.