Stress Distribution within the Peri-Implant Bone for Different Implant Materials Obtained by Digital Image Correlation

Stress distribution and its magnitude during loading heavily influence the osseointegration of dental implants. Currently, no high-resolution, three-dimensional method of directly measuring these biomechanical processes in the peri-implant bone is available. The aim of this study was to measure the influence of different implant materials on stress distribution in the peri-implant bone. Using the three-dimensional ARAMIS camera system, surface strain in the peri-implant bone area was compared under simulated masticatory forces of 300 N in axial and non-axial directions for titanium implants and zirconia implants. The investigated titanium implants led to a more homogeneous stress distribution than the investigated zirconia implants. Non-axial forces led to greater surface strain on the peri-implant bone than axial forces. Thus, the implant material, implant system, and direction of force could have a significant influence on biomechanical processes and osseointegration within the peri-implant bone.

"Utility of Smartphone-based Three-dimensional Surface Imaging for Digital Facial Anthropometry"

Background

The utilization of three-dimensional (3D) surface imaging for facial anthropometry is a significant asset for patients undergoing maxillofacial surgery. Notably, there have been recent advancements in smartphone technology that enable 3D surface imaging.In this study, anthropometric assessments of the face were performed using a smartphone and a sophisticated 3D surface imaging system.

Methods

30 healthy volunteers (15 females and 15 males) were included in the study. An iPhone 14 Pro (Apple Inc., USA) using the application 3D Scanner App (Laan Consulting Corp., USA) and the Vectra M5 (Canfield Scientific, USA) were employed to create 3D surface models. For each participant, 19 anthropometric measurements were conducted on the 3D surface models. Subsequently, the anthropometric measurements generated by the two approaches were compared. The statistical techniques employed included the paired t-test, paired Wilcoxon signed-rank test, Bland-Altman analysis, and calculation of the intraclass correlation coefficient (ICC).

Results

All measurements showed excellent agreement between smartphone-based and Vectra M5-based measurements (ICC between 0.85 and 0.97). Statistical analysis revealed no statistically significant differences in the central tendencies for 17 of the 19 linear measurements. Despite the excellent agreement found, Bland-Altman analysis revealed that the 95% limits of agreement between the two methods exceeded ±3 mm for the majority of measurements.

Conclusion

Digital facial anthropometry using smartphones can serve as a valuable supplementary tool for surgeons, enhancing their communication with patients. However, the proposed data suggest that digital facial anthropometry using smartphones may not yet be suitable for certain diagnostic purposes that require high accuracy.

Patient's Perception of Outcome after Extracapsular Fractures of the Mandibular Condyle Differs from Objective Evaluation-Experience of a Third-Level Hospital

Background: The aim of this study is to assess patients' subjective perception of treatment outcome after extracapsular fractures of the mandibular condyle. Methods: A questionnaire survey regarding facial nerve palsy (FNP), malocclusion, pain, reduction in maximum mouth opening (MMO) and further discomfort after 3, 6, and 12 months was carried out. Patients aged 18 or more presenting with an extracapsular condylar fracture between 2006 and 2020 were identified by purposive sampling Questionnaires were received from 115 patients. Fractures were classified on the basis of the pre-treatment imaging, the way of treatment was obtained from patients' medical records. Data were analyzed using Pearsons' chi-square-test, descriptive statistics and Student's t-test. Results: 93.0% of the fractures were treated by open reduction and internal fixation (ORIF). MMO reduction was the most common post-treatment complication (55.6%). ORIF was associated with less pain after 3 months (p = 0.048) and lower VAS scores compared to conservative treatment (p = 0.039). Comminuted fractures were more frequently associated with post-treatment malocclusion (p = 0.048), FNP (p = 0.016) and MMO reduction (p = 0.001). Bilateral fractures were significantly accompanied by malocclusion (p = 0.029), MMO reduction (p = 0.038) and pain occurrence (p < 0.001). Conclusions: Patients report less pain after ORIF. Comminuted and bilateral fractures seem to be major risk factors for complications. Subjective perception of complications after extracapsular condylar fractures differs from objectively assessed data.

Animal Bite Injuries to the Face: A Retrospective Evaluation of 111 Cases

The treatment of bite wounds to the face is discussed controversially in relation to surgery and antibiotics. The aim of this study is a retrospective evaluation of 111 cases of animal bite injuries to the face that presented to our unit of oral and maxillofacial surgery over a 13-year period. Children under 10 years of age were predominantly involved. A total of 94.5% of the assessed injuries were caused by dogs. Wound infections occurred in 8.1%. Lackmann type II was the most common type of injury (36.9%). The perioral area was affected most frequently (40.5%). Primary wound closure was carried out in 74.8% of the cases. In 91.9% of the cases, antibiotic prophylaxis was prescribed. The most often administered type of antibiotic was amoxicillin with clavulanic acid (62.1%). Patients without antibiotics showed an increased infection rate without significance. Wound infections occurred significantly more frequently in wounds to the cheeks (p = 0.003) and when local flap reconstruction was necessary (p = 0.048). Compared to the other surgical treatment options, primary closure showed the lowest infection rates (4.8%, p = 0.029). We recommend antibiotic prophylaxis using amoxicillin with clavulanic acid and wound drains for wounds of Lackmann class II or higher. Primary closure seems to be the treatment of choice whenever possible.

Thin PDS Foils Represent an Equally Favorable Restorative Material for Orbital Floor Fractures Compared to Titanium Meshes

Orbital floor fractures (OFFs) are common injuries of the midface and may result in long-term complications. The aim of this study was to compare two restoration materials, PDS foils and titanium meshes, with regards to (1) clinical outcome and (2) reduction in orbital volume. The monocentric discovery cohort was analyzed retrospectively and included 476 patients with OFFs treated between 2010 and 2020. A subcohort of 104 patients (study cohort) with isolated OFFs and available high-resolution imaging material was used for volume measurements. Postoperative complications were not significantly different between patients treated with different restoration materials. Prevalence of revision surgery was significantly higher in patients treated with thick PDS foils (25 mm). OFFs treated with PDS foils and titanium meshes showed a significant reduction in orbital volume (p = 0.0422 and p = 0.0056, respectively), however, this volume decrease was significantly less pronounced in patients treated with PDS foils alone (p = 0.0134). Restoration using PDS foil in an isolated OFF reduces the orbital volume to a lesser extent than titanium mesh. Class III patients according to the classification of Jaquiéry with a missing bony ledge medial to the infraorbital fissure particularly benefit from restoration with PDS foils due to a lower reduction in the orbital volume. Regarding short- and long-term postoperative complications, a PDS foil thickness of 0.15 mm appears equivalent to titanium mesh in the treatment of OFFs.

Novel Three-Dimensional and Non-Invasive Diagnostic Approach for Distinction between Odontogenic Keratocysts and Ameloblastomas

Aim of this study was to demonstrate the diagnostic ability to differentiate odontogenic keratocysts (OKCs) from ameloblastomas (AMs) based on computed tomography (CT) or cone beam computed tomography (CBCT) scans. Preoperative CT and CBCT scans from 2004 to 2019 of OKCs and AMs were analyzed in 51 participants. Lesions were three-dimensionally (3D) assessed and Hounsfield units (HU) as well as gray scale values (GSV) were quantified. Calculated HU spectra were compared within the same imaging modalities using unpaired t-tests and correlated with participants characteristics by calculating Pearsons correlation coefficients. Within the CT scans, AMs had highly significantly higher HU values compared to OKCs (43.52 HU and 19.79 HU, respectively; p < 0.0001). Analogous, within the CBCT scans, AMs had significantly higher GSV compared to OKCs (-413.76 HU and -564.76 HU, respectively; p = 0.0376). These findings were independent from participants' gender and age, anatomical site, and lesion size, indicating that the HU- and GSV-based difference reflects an individual configuration of the lesion. HU and GSV spectra calculated from CT and CBCT scans can be used to discriminate between OKCs and AMs. This diagnostic approach represents a faster and non-invasive option for preoperative diagnosis of such entities and has potential to facilitate therapeutic decision making.

Tumor gene signatures that correlate with release of extracellular vesicles shape the immune landscape in head and neck squamous cell carcinoma

Head and neck squamous cell carcinomas (HNSCCs) evade immune responses through multiple resistance mechanisms. Extracellular vesicles (EVs) released by the tumor and interacting with immune cells induce immune dysfunction and contribute to tumor progression. This study evaluates the clinical relevance and impact on anti-tumor immune responses of gene signatures expressed in HNSCC and associated with EV production/release. Expression levels of two recently described gene sets were determined in The Cancer Genome Atlas Head and Neck Cancer cohort (n = 522) and validated in the GSE65858 dataset (n = 250) as well as a recently published single-cell RNA sequencing dataset (n = 18). Clustering into HPV(+) and HPV(-) patients was performed in all cohorts for further analysis. Potential associations between gene expression levels, immune cell infiltration, and patient overall survival were analyzed using GEPIA2, TISIDB, TIMER, and the UCSC Xena browser. Compared to normal control tissues, vesiculation-related genes were upregulated in HNSCC cells. Elevated gene expression levels positively correlated (P < 0.01) with increased abundance of CD4(+) T cells, macrophages, neutrophils, and dendritic cells infiltrating tumor tissues but were negatively associated (P < 0.01) with the presence of B cells and CD8(+) T cells in the tumor. Expression levels of immunosuppressive factors NT5E and TGFB1 correlated with the vesiculation-related genes and might explain the alterations of the anti-tumor immune response. Enhanced expression levels of vesiculation-related genes in tumor tissues associates with the immunosuppressive tumor milieu and the reduced infiltration of B cells and CD8(+) T cells into the tumor.

Direct Anthropometry Overestimates Cranial Asymmetry-3D Digital Photography Proves to Be a Reliable Alternative

This study compared manual and digital measurements of plagiocephaly and brachycephaly in infants and evaluated whether three-dimensional (3D) digital photography measurements can be used as a superior alternative in everyday clinical practice. A total of 111 infants (103 with plagiocephalus and 8 with brachycephalus) were included in this study. Head circumference, length and width, bilateral diagonal head length, and bilateral distance from the glabella to the tragus were assessed by manual assessment (tape measure and anthropometric head calipers) and 3D photographs. Subsequently, the cranial index (CI) and cranial vault asymmetry index (CVAI) were calculated. Measured cranial parameters and CVAI were significantly more precise using 3D digital photography. Manually acquired cranial vault symmetry parameters were at least 5 mm lower than digital measurements. Differences in CI between the two measuring methods did not reach significance, whereas the calculated CVAI showed a 0.74-fold decrease using 3D digital photography and was highly significant (p < 0.001). Using the manual method, CVAI calculations overestimated asymmetry, and cranial vault symmetry parameters were measured too low, contributing to a misrepresentation of the actual anatomical situation. Considering consequential errors in therapy choices, we suggest implementing 3D photography as the primary tool for diagnosing deformational plagiocephaly and positional head deformations.

OSCC in Never-Smokers and Never-Drinkers Is Associated with Increased Expression of Tumor-Infiltrating Lymphocytes and Better Survival

The aim of this study was to investigate the clinical, histopathologic, and immunologic differences of oral squamous cell carcinoma of never-smokers/never-drinkers and smokers/drinkers. Immunohistochemical staining for CD4, CD8, FoxP3, CD1a, and p16 was performed in 131 oral squamous cell carcinomas from smokers/drinkers and never-smokers/never-drinkers. Associations of smoking/drinking status with clinicopathologic data, immunohistochemical antibody expression, and survival were examined. Oral squamous cell carcinoma in never-smokers/never-drinkers was associated with the female gender (p < 0.001). Never-smokers/never-drinkers were older at diagnosis than smokers/drinkers (p < 0.001). Never-smokers/never-drinkers had more tumors in the maxilla, mandible, and tongue (p < 0.001). Pre-existing oral potentially malignant disorders appeared to be more common in never-smokers/never-drinkers (p < 0.001). Perineural invasion was more common in smokers/drinkers (p = 0.039). Never-smoking/never-drinking was associated with better overall survival (p = 0.004) and disease-specific survival (p = 0.029). High CD4+ T cell infiltration was associated with never-smoking/never-drinking (p = 0.008). Never-smokers/never-drinkers also showed increased CD8+ T cell infiltration (p = 0.001) and increased FoxP3+ Treg infiltration (p = 0.023). Furthermore, the total group of tumor-infiltrating lymphocytes was associated with never smoking/never drinking (p = 0.005). To conclude oral squamous cell carcinoma of the never-smokers/never-drinkers appears to be a distinct type of tumor, as it appears to have unique clinical and pathologic features and a more immunogenic microenvironment.

TGFβ carrying exosomes in plasma: potential biomarkers of cancer progression in patients with head and neck squamous cell carcinoma

OBJECTIVES

Contributions of TGFβ to cancer progression are well documented. However, plasma TGFβ levels often do not correlate with clinicopathological data. We examine the role of TGFβ carried in exosomes isolated from murine and human plasma as a contributor to disease progression in head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

The 4-nitroquinoline-1-oxide (4-NQO) mouse model was used to study changes in TGFβ expression levels during oral carcinogenesis. In human HNSCC, TGFβ and Smad3 protein expression levels and TGFB1 gene expression were determined. Soluble TGFβ levels were evaluated by ELISA and TGFβ bioassays. Exosomes were isolated from plasma using size exclusion chromatography, and TGFβ content was quantified using bioassays and bioprinted microarrays.

RESULTS

During 4-NQO carcinogenesis, TGFβ levels in tumour tissues and in serum increased as the tumour progressed. The TGFβ content of circulating exosomes also increased. In HNSCC patients, TGFβ, Smad3 and TGFB1 were overexpressed in tumour tissues and correlated with increased soluble TGFβ levels. Neither TGFβ expression in tumours nor levels of soluble TGFβ correlated with clinicopathological data or survival. Only exosome-associated TGFβ reflected tumour progression and correlated with tumour size.

CONCLUSIONS

Circulating TGFβ+ exosomes in the plasma of patients with HNSCC emerge as potential non-invasive biomarkers of disease progression in HNSCC.

Two-Dimensional Post-Traumatic Measurements of Orbital Floor Blowout Fractures Underestimate Defect Sizes Compared to Three-Dimensional Approaches

Orbital floor fractures represent a common fracture type of the midface and are standardly diagnosed clinically as well as radiologically using linear measurement methods. The aim of this study was to evaluate the accuracy of diagnostic measurements of isolated orbital floor fractures based on two-dimensional (2D) and three-dimensional (3D) measurement techniques. A cohort of 177 patients was retrospectively and multi-centrically evaluated after surgical treatment of an orbital floor fracture between 2010 and 2020. In addition to 2D and 3D measurements of the fracture area, further fracture-related parameters were investigated. Calculated fracture areas using the 2D measurement technique revealed an average area of 287.59 mm², whereas the 3D measurement showed fracture areas with a significantly larger average value of 374.16 mm² (p < 0.001). On average, the 3D measurements were 1.53-fold larger compared to the 2D measurements. This was observed in 145 patients, whereas only 32 patients showed smaller values in the 3D-based approach. However, the process duration of the 3D measurement took approximately twice as long as the 2D-based procedure. Nonetheless, 3D-based measurement of orbital floor defects provides a more accurate estimation of the fracture area than the 2D-based procedure and can be helpful in determining the indication and planning the surgical procedure.

Statin Use Ameliorates Survival in Oral Squamous Cell Carcinoma-Data from a Population-Based Cohort Study Applying Propensity Score Matching

The anti-cancer properties of statins have attracted much attention recently, but little is known about the prognostic role of statins in oral squamous cell carcinoma (OSCC). In a retrospective approach, we analyzed a population-based cohort of 602 OSCC patients with primary curative tumor resection to negative margins and concomitant neck dissection between 2005-2017. Long-term medication with statins was correlated with overall survival (OAS) as well as recurrence-free survival (RFS) using uni- and multivariable Cox regression. Additionally, propensity score matching was applied to adjust for confounders. Statin use was present in 96 patients (15.9%) at a median age of 65.7 years. Statin treatment correlated with ameliorated survival in multivariable Cox regression in the complete cohort (OAS: HR 0.664; 95% CI 0.467-0.945, p = 0.023; RFS: HR 0.662; 95% CI 0.476-0.920, p = 0.014) as well as matched-pair cohort of OSCC patients (OAS: HR 0.691; 95% CI 0.479-0.997, p = 0.048; RFS: HR 0.694; 95% CI 0.493-0.976, p = 0.036) when compared to patients not taking statins at time of diagnosis. These findings were even more pronounced by sub-group analysis in the matched-pair cohort (age < 70 years). These data indicate that statin use might ameliorate the oncological outcome in primarily resected OSCC patients, but prospective clinical trials are highly recommended.

A20 as a Potential New Tool in Predicting Recurrence and Patient's Survival in Oral Squamous Cell Carcinoma

A20, known as a potent inhibitor of NF-κB signaling, has been characterized in numerous clinical as well as preclinical studies. Recently, especially in various malignant diseases, the prognostic and therapeutic relevance of A20 was investigated. In oral squamous cell carcinoma (OSCC) however, the characterization of A20 is uncharted territory. We analyzed a tissue microarray (TMA) of 229 surgically-treated OSCC patients (2003-2013). Immunohistochemical (IHC) stainings were performed for A20 and CD3; additionally, standard haematoxylin-eosin staining was applied. IHC findings were correlated with a comprehensive dataset, comprising clinical and pathohistological information. A20 expression was analyzed in tumor cells as well as in tumor infiltrating lymphocytes (TILs) and correlated with the overall survival (OS) and recurrence-free survival (RFS) using uni- and multivariable Cox regression. The median follow-up time was 10.9 years and the A20 expression was significantly decreased in CD3+ TILs compared to mucosa-infiltrating lymphocytes (MILs). In the Kaplan-Meier analyses, higher A20 expression in TILs was correlated with better OS (p = 0.017) and RFS (p = 0.020). In the multivariable survival analysis, A20 overexpression correlated with improved OS (HR: 0.582; 95% CI 0.388-0.873, p = 0.009) and RFS (HR 0.605; 95% CI 0.411-0.889, p = 0.011). Our results indicate a novel prognostic role for A20 in OSCC. Due to its elevated expression in TILs, further research is highly desirable, which therefore could offer new therapeutic opportunities for patients suffering from OSCC.

TIGIT Expression on Intratumoral Lymphocytes Correlates with Improved Prognosis in Oral Squamous Cell Carcinoma

(1) Background: T-cell immunoglobulin and ITIM domain (TIGIT) is a potential immunotherapeutic target in a variety of malignant entities, and antibody-based treatments are currently under investigation in clinical trials. While promising results were observed in patients with lung cancer, the role of TIGIT in oral squamous cell carcinoma (OSCC) as a biomarker as well as a therapeutic target remains elusive. Therefore, we evaluated the role of TIGIT as a prognostic factor in OSCC. (2) Methods: Here, we describe the results of a retrospective tissue microarray (TMA) OSCC cohort. Using immunohistochemistry, TIGIT expression was correlated with overall and recurrence-free survival (OAS and RFS, respectively). Additionally, in silico analysis was performed based on the TCGA Head and Neck Squamous Cell Carcinoma (HNSCC) cohort in order to correlate patients' survival with TIGIT and CD274 (encoding for PD-L1) gene expression levels. (3) Results: Database analysis revealed a beneficial outcome in OAS for tumor patients with high intraepithelial CD3-TIGIT-expression (n = 327). Hereby, OAS was 53.9 months vs. 30.1 months for patients with lower TIGIT gene expression levels (p = 0.033). In our retrospective OSCC-TMA cohort, elevated TIGIT levels on CD3+ cells correlated significantly with improved OAS (p = 0.025) as well as distant RFS (p = 0.026). (4) Conclusions: This study introduces TIGIT as a novel prognostic factor in OSCC, indicating the improved outcome of OSCC patients relative to their increased TIGIT expression. TIGIT might provide therapeutic implications for future immunotherapy in advanced-stage OSCC patients.

Retrospective three-dimensional analysis of bone resorption volumes of free microvascular scapular and fibular grafts

Defects in head and neck regions are standardly treated with microvascular grafts, such as free scapular (SFF) and fibular flaps (FFF), which are subject to a certain amount of bone resorption over time. The aim of this study was the 3-dimensional evaluation of bone resorption volume in both grafts. Over a period of 10 years, computed tomograms (CT) of patients with mandibular reconstructions with SFFs and FFFs were examined. The respective grafts were segmented as well as 3-dimensionally measured. Furthermore, factors such as gender, age, nicotine abuse, previous disease with type 2 diabetes, and adjuvant therapies, were examined for their influence. A total of 211 CT scans from 67 patients (40 SFFs and 27 FFFs) were included in the study. SFFs showed slightly higher median bone volumes (87.60% at 730 days and 86.55% at 1500 days) than FFFs (84.40% at 730 days and 82.10% at 1500 days). When final volumes were considered, FFFs had higher mean volume values (88.22%) than SFFs (83.82%), with significant correlation between resorption volume and time progression (r = 0.357, p = 0.024). All previously mentioned factors had no significant effect on bone resorption. Bone volumes of FFFs showed postoperative volume reductions similar to those of SFFs, with isolated SFFs having markedly lower volume values. The choice of a microvascular graft for reconstruction in the mandible proves difficult regarding bone resorption. The presented results may support decisions about future transplantations.

The influence of nanoporous anodic aluminum oxide on the initial adhesion of Streptococcus mitis and mutans

The use of nanoscale surface modifications offers a possibility to regulate the bacterial adherence behavior. The aim of this study was to evaluate the influence of nanoporous anodic aluminum oxide of different pore diameters on the bacterial species Streptococcus mitis and Streptococcus mutans. Nanoporous anodic aluminum oxide (AAO) surfaces with an average pore diameter of 15 and 40 nm, polished pure titanium and compact aluminum oxide (alumina) samples as reference material were investigated. S. mitis and mutans were evaluated for initial adhesion and viability after an incubation period of 30 and 120 min. After 30 min a significantly reduced growth of S. mitis and mutans on 15 nm samples compared to specimens with 40 nm pore diameter, alumina and titanium surfaces could be observed (p < .001). Even after 120 min incubation there was a significant difference between the surfaces with 15 nm pore diameter and the remaining samples (p < .001). AAO surfaces with a small pore diameter have an inhibitory effect on the initial adhesion of S. mitis and mutans. The use of such pore dimensions in the area of the implant shoulder represents a possibility to reduce the adhesion behavior of these bacterial species.