Application of organoselenium in inhibiting Candida albicans biofilm adhesion on 3D printed denture base material.

PURPOSE: Denture Stomatitis, a chronic mucosal inflammation associated with Candida albicans, is common among denture wearers. Several health conditions have been linked to chronic Candida infections. The complex, multifactorial nature of denture stomatitis requires the continuous pursuit of effective long-term solutions. The present in vitro study investigated the effect of incorporating organoselenium into 3D-printed denture base resin on C. albicans adhesion and biofilm formation. MATERIALS AND METHODS: Thirty disks were fabricated using 3D-printed denture base resin and assigned to three experimental groups (10/group): disks without organoselenium (control), disks with 0.5% organoselenium (0.5%SE), and disks with 1% organoselenium (1%SE). Each disk was incubated with approximately 1 × 106 cells/mL of C. albicans for 48 h. Microbial viability (CFU/mL) was quantified by the spread plate method, while Confocal laser scanning microscopy and scanning electron microscope were performed for quantifying the biofilm thickness and examining biofilm morphology, respectively. Data were analyzed using One-way ANOVA with Tukey's multiple comparisons test. RESULTS: CFU/mL was significantly (p < 0.05) higher in Control when compared with 0.5%SE and 1%SE, but no significant difference between 0.5%SE and 1%SE. A similar trend was observed with biofilm thickness except that there was no significant difference between the Control and 0.5%SE. There was C. albicans biofilm adhesion on the Control disks, with yeast cells and hyphae formation, whereas on 0.5%SE and 1%SE, there was inhibition of yeast cells transition to hyphae formation. CONCLUSIONS: Incorporation of organoselenium into 3D-printed denture base resin was effective in reducing C. albicans biofilm formation and growth on denture base material.

Bur Choice When Removing Zirconia Restorations.

PURPOSE: Removal of zirconia restorations can be challenging and time consuming, requiring dental burs with optimal cutting efficiency to minimize iatrogenic complications. Yet, there are very few burs marketed for this purpose and little evidence of their comparative benefit. This study evaluated one specialized bur and compared its cutting efficiency with three general-purpose burs (one single use and two multiple uses). MATERIALS AND METHODS: This study was designed to assess the cutting efficiency of 4 burs on a high-strength zirconia substrate. One of these burs is a multiple-use bur marketed for high-strength ceramics (Komet 4ZR), another is a single-use general-purpose bur (Piranha 837.012 coarse), and two are multiple-use general-purpose burs (Brassler 6837.31.012C coarse and Komet 6837.314.012 coarse). The cutting efficiency of each bur was determined by measuring the time taken to perform serial 2 mm cuts into a block of zirconia. Ten burs in each group were tested with repeated cuts until the time taken for a 2 mm cut was twice that of the first 2 mm cut (50% loss of efficiency). This study was performed under reproducible conditions using a custom-designed and fabricated rig assembly. RESULTS: The results demonstrated a statistically significant difference in the cutting efficiency between bur types. The single-use general-purpose bur (Piranha 837.012) was the most efficient for all cut numbers p <2.2 × 10-16 . The performance of all burs decreased with each cut, with cutting efficiency dependent on time point/cut number (p = 0.02). The rate of deterioration varied between burs, but this difference was not sufficient to be statistically significant. CONCLUSIONS: This study demonstrated that a single-use bur is more efficient than 3 multiple-use burs. The cutting efficiency of a single-use general-purpose bur (Piranha 837.012 coarse) on Cerec Zirconia Mono L was statistically superior to that of multiple patient use burs in this study, including one marketed for use on high-strength ceramics. Because single-use burs are comparatively inexpensive and require no sterilization, they should be strongly considered for the removal of zirconia restorations.

Critical Thinking in Dental Students and Experienced Practitioners Assessed by the Health Sciences Reasoning Test.

To date, there has been a lack of published studies examining the validity of the Health Sciences Reasoning Test (HSRT) to assess critical thinking among dental students. The aim of this study was to examine the construct validity of the HSRT using a novice-expert model consisting of first-year dental students as novices and experienced general dentists as experts. Novice cohort subjects were recruited from all 105 students in the first-year dental school class at the University of Texas Health Science Center at San Antonio during a regularly scheduled course in August 2015. A total of 83 students participated, for a 79% response rate. Thirty individuals personally recruited from the same school's faculty and from private practitioners made up the expert cohort. The results showed that the adjusted mean overall score for the expert cohort (25.31) was significantly higher than that of the novice cohort (22.64) (p=0.04). The expert cohort achieved higher adjusted mean scores in all scales (Induction, Deduction, Analysis, Inference, and Evaluation), with the difference in the Analysis scale being significant (p=0.02). In this study, experienced general dentists achieved significantly better overall scores on the HSRT as compared to first-year dental students, suggesting the instrument was able to measure differences between novice and expert. Further efforts to validate the instrument in a dental education setting and to understand its correlation with strategies and practices aimed at developing critical thinking in dental students are warranted.

The chamfer finish line: preclinical student performance using different bur designs.

The primary purposes of this investigation were to evaluate sophomore dental student performance in the production of a chamfer finish line using two diamond bur types-a round-ended bur and a torpedo-shaped bur-and to gain student feedback about their preferences for bur type. Fifty students took part in the study, each of whom prepared the buccal surfaces of two mandibular molar typodont teeth, producing chamfer finish lines. Students prepared both teeth in the same laboratory session and were randomly assigned to two groups that were required to prepare the first of the two molars with a specific bur type. The prepared chamfer finish lines were scored and the data analyzed using the Wilcoxon signed-rank test. Student performance was significantly better when the round-ended bur was used (p=0.005). Student feedback was collected with a survey that consisted of four questions and the opportunity to provide write-in comments. In response to the question "Overall, was one bur type better?" 58 percent of the students preferred the round-ended bur for creating a chamfer finish line. The most frequent write-in comment, made by twelve of the fifty students, criticized the torpedo-shaped bur for creating finish lines that were too shallow or too long.

Functional impressions for complete denture fabrication. A modified jump technique.

Tissue conditioners are used with great success in dentistry as functional impression materials for rebasing removable prostheses. In the rebase procedure, a functional impression is made in an existing denture to create a master cast. The orientation of the occlusal surface to the underlying tissue surface is captured with a reline jig or denture flask and transferred to the new denture base in what is called a "jump" in laboratory jargon. Functional impression methods are not commonly considered, however, for the fabrication of new dentures despite their popularity and ease of use. This article describes a modified jump technique for remaking complete dentures. The method uses functional impressions in existing maxillary and mandibular dentures to create master casts and to act as stabilized carriers for jaw relation records. More precise esthetic and phonetic assessments of the existing prostheses are accommodated, and prescriptive changes may be referenced to the current tooth arrangement.