PURPOSE This in vitro study investigates the effect of different post-rinsing times and methods on the trueness and precision of denture base resin manufactured through stereolithography. MATERIALS AND METHODS Ninety clear photopolymer resin specimens were fabricated and divided into nine groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5, 10, and 15 min using three methods-automated, ultrasonic cleaning, and hand washing. The specimens were polymerized for 30 min at 40℃. For trueness, the scanned intaglio surface of each SLA denture base was superimposed on the original standard tessellation language (STL) file using best-fit alignment (n = 10). For precision, the scanned intaglio surface of the STL file in each specimen group was superimposed across each specimen (n = 45). The root mean square error (RMSE) was measured, and the data were analyzed statistically through one-way ANOVA and Tukey test (α < .05). RESULTS The 10-min automated group exhibited the lowest RMSE. For trueness, this was significantly different from specimens in the 5-min hand-washed group ( P < .05). For precision, this was significantly different from those of other groups ( P < .05), except for the 15-min automated and 15-min ultrasonic groups. The color map results indicated that the 10-min automated method exhibited the most uniform distribution of the intaglio surface adaptation. CONCLUSION The optimal postprocessing rinsing times and methods for achieving clear photopolymer resin were found to be the automated method with rinsing times of 10 and 15 min, and the ultrasonic method with a rinsing time of 15 min.

Background Complete tooth losses are still being major problems which resulted in lesser quality of life especially for elderly patients. However, there are still lack of questionnaire to evaluate the treatment outcome from the patient’s aspect. The objective of this study is to evaluate the reliability and validity of the Patient’s Denture Assessment-Thai version (PDA-T), then use this questionnaire to assess patient satisfaction with complete denture treatment outcome also investigates the factors involving their satisfaction. Methods The subjects comprised 120 edentulous adult patients (49 men/71 women; average age 70 years-old) from the Prosthodontic and the Geriatric Dentistry and Special Patients Care Clinic at the Faculty of Dentistry, Chulalongkorn University during 2019 March‒2020 March. The patients were divided into two groups: the group experienced (Exper) (n = 54) with wearing complete dentures, and the non-experienced (NonExper) group (n = 66). The patients used the validated PDA-T to self-assess their treatment at different times. The Exper group completed the questionnaire at t0 (during treatment), t0.5 (2‒8-weeks after t0), and t1 (final follow-up). The NonExper group completed the questionnaire only at t1. Results In the Exper group, Cronbach’s α and average inter-item correlation was 0.95 (range 0.76‒0.95) and 0.47 (range 0.57‒0.83), respectively. The intraclass correlation coefficients (n = 18, 95% confidence interval) were 0.98 overall. The paired t-test (p < 0.05) between t0 and t1 indicated a significant difference between t0 and t1 in every PDA-T topic, and the effect size was 1.71. In the NonExper group, the Pearson correlation analysis indicated no significant correlation between the patients' demographics and masticatory function. Conclusion The reliability and validity of the PDA-T indicate it is a valuable tool for evaluating complete denture treatment. Treatment success affected the patients' satisfaction but was not associated with the type of doctors, genders, ages, or educational level.

Additive manufacturing has revolutionized the fabrication of complete dentures. However, this process involves support structure, which is a construction part that holds the specimen during printing, and may prove to be disadvantageous. Therefore, this in vitro study compared the effect of support structure reduction on various volume and area distributions of a 3D-printed denture base to determine optimal parameters based on accuracy. Methods: A complete maxillary denture base construction file was used as reference. Twenty denture bases were 3D printed under four conditions (total n=80): no support structure reduction (control), palatal support structure reduction (Condition P), border support structure reduction (Condition B), and palatal and border support structure reduction (Condition PB). Printing time and resin consumption were also recorded. The intaglio surface trueness and precision of all acquired data were exported to a 3D analysis software, and the dimensional changes to the denture base were analyzed using the root-mean-square estimate (RMSE) to assess geometric accuracy and generate color map patterns. Nonparametric Kruskal-Wallis and Steel-Dwass tests (α=0.05) analyzed the accumulated data. Results: Control had the lowest RMSE values for trueness and precision. Nevertheless, it demonstrated a significantly lower RMSE than that of Condition B (P=0.02) in precision. Owing to negative deviation at the palatal region, Conditions P and PB had higher retention than Control and Condition B regarding the color map pattern. Conclusions: Within the limitations of this study, the reduction of palatal and border support structures showed optimal accuracy with resource and cost savings.

Implant overdentures have become a reliable treatment option for edentulous patients because of their enhanced retention, stability, masticatory performance, and higher patient satisfaction compared to conventional complete dentures [1,2]. Mini-implants have a reduced diameter of <3.0 mm and are manufactured using biocompatible materials used for manufacturing standard-sized implants [3]. Mini-implant overdentures are beneficial alternatives for elderly patients with severely resorbed mandibles or physical conditions that hinder advanced surgeries such as bone reshaping or grafting when using standard-sized implants [4]. They are also associated with a reduced cost, as the relatively high cost of standard-sized implant overdentures could limit patients' willingness to accept treatment [5]. In addition, they require minimal intervention and lower operative time compared to standard-sized implants[6] and demonstrate adequate survival rates [7]. Despite these advantages, mini-implants reportedly have lower mechanical strength and increased risks of implant fractures and peri-implant bone damage [4,8]. Clinical studies have highlighted the threat of fatigue fractures in implants with diameters <3.5 mm. In addition, mini-implants showed considerably low strength in in vitro monotonic loading tests, indicating a risk of fracture [9,10]. Therefore, while determining the applications of implants with a diameter ≤3 mm, practitioners should exercise extreme caution, particularly in selecting implant designs that have been proven to affect the mechanical response of implants. The optimal mini-implant J Prosthodont Res. 2022; **(**):