Research Spotlight

Shokri, T., Saadi, R., Wang, W., Reddy, L. and Ducic, Y. (2020). “Facial Transplantation: Complications, Outcomes, and Long-Term Management Strategies.” Semin Plast Surg 34(4): 245-253.

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Within the past two decades, vascularized facial composite allotransplantation has evolved into a viable option in the reconstructive surgeons’ armamentarium for patients with extensive facial disfigurements. As it has expanded the frontiers of microsurgical reconstructive techniques, facial transplantation has come to garner widespread interest within both the medical community and the general public. The procedure has established itself as an amalgamation of the forefronts of reconstructive microsurgery, immunology, and transplantation science. Therein too lies its complexity as multifaceted scientific developments are met with ethical and social issues. Both patients and physicians are faced with the everlasting challenges of immunosuppression regimens and their inherent complications, long-term aesthetic and functional considerations, the role of revision procedures, and the inevitable psychosocial implications. This article reflects on the medical and surgical advancements in facial transplantation surgery and highlights anticipated future challenges. It aims to encourage discussion regarding anticipated barriers to current practice and suggest future directions as we transition into the next phase of facial allograft transplantation.\

Manila, N.G., Tahmasbi Arashlow, M., Ehlers, S., Liang, H. and Nair, M.K. (2020). “Cone-beam computed tomographic imaging of silent sinus syndrome: A case series and a literature review.” Imaging Sci Dent 50(4): 365-371.

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While silent sinus syndrome (SSS) is familiar to otolaryngologists and ophthalmologists, it is a rare clinical entity in dentistry and is likely to be underdiagnosed due to dentists’ lack of awareness of this condition. SSS presents a diagnostic challenge to dentists, as patients typically have no history of trauma or sinusitis. The characteristic feature of SSS is a gradual retreat of the maxillary sinus walls, resulting in enophthalmos and hypoglobus. Multidetector (multislice) computed tomography is the imaging modality of choice for SSS and other paranasal sinus diseases. Cone-beam computed tomography promises to be an alternative low-dose imaging modality. This report describes 3 cases of SSS in adults, who had no identified clinical symptoms except diminutive and opacified maxillary sinuses, as well as the inward bowing of the sinus walls as noted on cone-beam computed tomographic imaging.

Gakis, P., Kontogiorgos, E., Zeller, S. and Nagy, W.W. (2020). “Effect of firing and fabrication technique on the marginal fit of heat-pressed lithium disilicate veneers.” J Prosthet Dent Dec 16;S0022-3913(20)30695-8. [Epub ahead of print].

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STATEMENT OF PROBLEM: Studies on the fit of heat-pressed anterior lithium disilicate veneers are sparse, and whether fit is affected by glaze firing or ceramic addition is unclear. PURPOSE: The purpose of this in vitro study was to evaluate and compare the marginal fit of heat-pressed anterior lithium disilicate veneers (IPS e.max Press) fabricated with the staining or cutback technique by using 3-dimensional analysis. MATERIAL AND METHODS: Two groups of heat-pressed maxillary left central incisor lithium disilicate veneers were fabricated (n=10) differing only in core thickness and the fabrication process. The tooth preparation was standardized at 0.6 mm cervical and middle third and 0.7 mm incisal third, with 1.5 mm of incisal reduction. Group S (staining) was an anatomic contour veneer with 1 glaze firing. Group CB (cutback) had a cutback core of 0.6 mm on the cervical and middle third and 0.5 mm on the incisal areas for ceramic application with 3 firings (wash, incisal, and glaze firing). The amount of ceramic application was standardized, and all veneers had identical final dimensions. Marginal fit was evaluated at 2 stages: after pressing the copings (control) and after glaze firing or ceramic addition using the virtual replica technique and 3-dimensional analysis. The wax copings were invested, eliminated, and pressed with IPS e.max lithium disilicate high translucency ingots, and the overall marginal fit and change in marginal fit after firing were measured in the cervical, mesial, distal, and incisal areas. The Shapiro-Wilk test was used to evaluate normality. Repeated-measures ANOVAs were used to explore differences between the 2 groups (S and CB) as per time (before and after firing) for each location (cervical, mesial, distal, and incisal) (α=.05). RESULTS: A statistically significant change in marginal fit after firing was found for the mesial and distal areas of the CB group (P<.05). In all other areas of measurements, no statistically significant differences were found (P>.05). The mean ±standard deviation marginal fit of group S was 63 ±13 μm and 62 ±9 μm for group CB. CONCLUSIONS: The results suggest that firing affects the marginal fit of heat-pressed anterior lithium disilicate veneers fabricated with the cutback technique but not for the staining technique.

Chang, B., Ma, C. and Liu, X. (2020). “Nanofibrous Tubular Three-Dimensional Platform for Single Dental Pulp Stem Cell Polarization.” ACS Appl Mater Interfaces 12(49): 54481-54488.

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Dental pulp stem cells (DPSCs) are the primary stem cell source for regenerative endodontics. DPSCs need to undergo a polarization process and retain the permanent polarization status to perform the function of odontoblasts. However, the factors that control DPSC polarization and its underlying mechanism remain unknown. In this study, we established a unique nanofibrous tubular three-dimensional (3D) platform to explore DPSC polarization. The 3D platform has a “clean” background and confines one single DPSC in each microisland of the platform; therefore, it is capable of deciphering any signal that initiates or regulates DPSC polarization. Using the biomimetic platform, we identified that the nanofibrous tubular architecture is the crucial factor to initiate DPSC polarization. Dynamic morphological observation showed that the cellular process of the polarized DPSCs continuously extended and reached a plateau at 72 h. Meanwhile, Golgi apparatus, a cell polarization marker, continuously moved from a juxtanuclear region, passed the nucleus, and eventually settled down at a final position that was a few micrometers away from the nucleus. Inhibition of microfilament and microtubule polymerization demonstrated the indispensable role of cytoskeleton reorganization in modulating DPSC polarization. In addition, cell tension was involved in the regulation of DPSC polarization. The findings of this work expand the in-depth understanding of DPSC polarization, which helps design new bioinspired materials for regenerative endodontics.

Malagise, C.J., Khalighinejad, N., Patel, Y.T., Jalali, P. and He, J. (2020). “Severe Pain Following Endodontic Surgery: An Analysis of Incidence and Risk Factors.” J Endod Dec 22;S0099-2399(20)30967-5. [Epub ahead of print].

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INTRODUCTION: The aim of this study was to determine the prevalence and characteristics of postoperative pain following endodontic microsurgery, and to identify potential predictors for severe pain. MATERIALS AND METHODS: One hundred seventy-three patients who underwent endodontic microsurgery at a private practice were included in the study. The patients were asked to fill out a questionnaire to assess their post-operative pain levels for five days following surgery. The questionnaires were analyzed to record the changes in pain levels over time. The presence and size of preoperative lesion and bone thickness were determined on the preoperative CBCT scans. Statistical analyses were performed to identify predictors for developing severe pain following surgery. A binary logistic regression model was established to predict the occurrence of severe pain. RESULTS: Severe pain was most prevalent on day 1 (17%), and gradually decreased until a small increase on day 5. The average pain level also peaked on day 1 postoperatively and gradually decreased afterwards. No significant difference was found between patients who reported severe pain and those who did not report severe pain regarding tooth position (anterior vs. posterior), lesion size and presence of fenestration. However, sex, age, and bone thickness were all significant predictors of severe postoperative pain, with odds ratios of 2.8, 0.96, and 1.41, respectively. CONCLUSION: Severe pain was reported only in a small number of patients after endodontic microsurgery. Younger patients, females, and patients with thicker bone covering the apex are significantly more likely to develop severe pain.