Effect of storage temperature on the dimensional stability of DLP printed casts.

STATEMENT OF PROBLEM: Despite studies focusing on the accuracy and dimensional stability of additive manufacturing, research on the impact of storage conditions on these properties of 3-dimensional (3D) printed objects is lacking. PURPOSE: The purpose of this in vitro study was to investigate the influence of storage temperature on the dimensional stability of digital light processing (DLP) printed casts and to determine how different locations in printed casts react differently. MATERIAL AND METHODS: A completely dentate maxillary typodont model was digitized with a desktop laser scanner. The typodont was subsequently modified with a software program by adding cuboids with a side length of 3 mm on both maxillary central incisors, first molars, and second molars. The file was saved in the standard tessellation language (STL) format. The modified digitized typodont was then processed through the DLP technology printing process with a desktop DLP printer and photopolymerizing resin. The casts were printed 32 times and stored in sealed plastic bags, shielded from light, and subjected to 4 different temperature conditions (-20 °C, 4 °C, 20 °C, and 37 °C, n=8 each). The cuboids on the central incisors were labeled as the P1 group, first molars as the P2 group, and second molars as the P3 group. The distance between the cuboids was measured 5 times, with results recorded immediately after cast production and at 1, 2, 3, 5, 7, 14, and 28 days after. Repeated analysis of variance (ANOVA) and the Tukey honestly significant difference (HSD) test were used to compare the recorded values among the groups (α=.05). RESULTS: In the P1 group, the casts stored at -20 °C exhibited the smallest overall size change, with a mean ±standard deviation volume of 99.42 ±0.04% compared with the original casts after 28 days of storage. This was followed by the casts stored at 4 °C, 20 °C, and 37 °C, with remaining volumes of 99.39 ±0.06% (P=.139), 99.14 ±0.08% (P<.001), and 98.96 ±0.03% (P<.001), respectively. For the P2 and P3 groups, casts stored at 4 °C retained the most volume at 99.82 ±0.01%, whereas those stored at -20 °C, 20 °C, and 37 °C underwent greater changes, with remaining volumes of 99.66 ±0.03%, 100.32 ±0.02%, and 100.44 ±0.02%, respectively (P<.001). The P3 group exhibited a similar trend to that of the P2 group, with the casts stored at 4 °C remaining closest to the original dimensions at 99.86 ±0.02%, while casts stored at -20 °C showed 99.73 ±0.03% of the original volume and those stored at 20 °C and 37 °C expanded with volumes of 100.37 ±0.03% and 100.48 ±0.03%, respectively (P<.001). CONCLUSIONS: DLP printed casts stored at 4 °C exhibited the greatest overall dimensional stability, followed sequentially by those stored at -20 °C, 20 °C, and 37 °C. Additionally, the study confirmed that the posterior and anterior teeth regions of DLP printed casts respond differently to different storage temperatures.

A phase I study of the Wee1 kinase inhibitor adavosertib (AZD1775) in combination with chemoradiation in cervical, upper vaginal, and uterine cancers.

OBJECTIVE: Wee1 kinase is a crucial regulator of the G2/M checkpoint which prevents entry of damaged DNA into mitosis. Adavosertib (AZD1775), a selective inhibitor of Wee1, induces G2 escape and increases cytotoxicity when combined with DNA damaging agents. We aimed to evaluate the safety and efficacy of adavosertib in combination with definitive pelvic radiotherapy and concurrent cisplatin in patients with gynecological cancers. METHODS: A multi-institutional, open-label phase I trial was designed to assess dose escalation (3+3 design) of adavosertib in combination with standard chemoradiation. Eligible patients with locally advanced cervical, endometrial or vaginal tumors were treated with a 5-week course of pelvic external beam radiation 45-50 Gy in 1.8-2 Gy daily fractions plus concurrent weekly cisplatin 40 mg/m2 and adavosertib 100 mg/m2 on days 1, 3 and 5 of each week during chemoradiation. The primary endpoint was to determine the recommended phase II dose of adavosertib. Secondary endpoints included toxicity profile and preliminary efficacy. RESULTS: Ten patients were enrolled (nine locally advanced cervical and one endometrial cancer). Two patients experienced a dose-limiting toxicity at dose level 1 (adavosertib 100 mg by mouth daily on days 1, 3 and 5), including one patient with grade 4 thrombocytopenia, and one with treatment hold >1 week due to grade 1 creatinine elevation and grade 1 thrombocytopenia. At dose level -1 (adavosertib 100 mg by mouth daily on days 3 and 5), one out of five patients enrolled had a dose-limiting toxicity in the form of persistent grade 3 diarrhea. The overall response rate at 4 months was 71.4%, including four complete responses. At 2 years follow-up, 86% of patients were alive and progression-free. CONCLUSION: The recommended phase II dose could not be determined due to clinical toxicity and early trial closure. Preliminary efficacy appears promising, yet selecting the adequate dose/schedule in combination chemoradiation warrants further investigation to limit overlapping toxicities.

Evaluation of the marginal adaptation and gingival status of full-crown restorations using an intraoral camera.

OBJECTIVE: The purpose of this study was to compare the usefulness of intraoral photographs, acquired with a household intraoral camera operating in conventional, calibrated, and polarized modes, with clinical examinations for assessing the marginal adaptation and gingival status of full-crown restorations. METHODS: Clinical examinations were performed by a prosthodontist who classified the marginal adaptation of full-crown restorations according to FDI World Dental Federation criteria, and a periodontal expert who classified gingival status according to the Modified Gingival Index (MGI). The margins and gingival status of the conventional, calibration, and polarization groups of full-crown restorations were independently assessed by three evaluators who obtained photographs using an intraoral camera. Cases where at least two of three assessors were in agreement were analyzed using Cohen's kappa coefficient and the chi-square test, and the sensitivity and specificity were calculated. RESULTS: The conventional, calibration, and polarization groups differed significantly in marginal and gingival status of full-crown restorations. In the calibration group, there was good agreement between the camera-based and oral clinical examinations in terms of the gingival status of full-crown restorations (kappa = 0.945), with 100% sensitivity and 91.67% specificity; this was also the case in the polarization group with respect to the margins of full-crown restorations (kappa = 0.917, sensitivity = 97.22%, specificity = 94.44%). CONCLUSIONS: An intraoral camera with black and white calibrated images is useful to assess the gingival status of full-crown restorations. Polarization mode can be used to assess the marginal adaptation of full-crown restorations. The camera is a feasible and valid diagnostic aid.