[Metronidazole - spectrum of activity, use and side effects]

This contribution gives an overview of the use, therapeutic effects and side effects of the antibiotic substance Metronidazole. Metronidazole is effective in the treatment support of paradontitis, microbial-caused halitosis, perioral skin infections and odontogenic hard or soft tissue abscess formations related to anaerobic bacterial infections. Due to its anti- parasitic effect, Metronidazole is also effective in the treatment of protozoa. In adults and children from 12 years on, 200 mg Metronidazole to a maximum of 2000 mg Metronidazole per day can be administered. In children below 12 years of age, an antibiotic dose of Metronidazole between 20 to 30 mg per kilogram body weight is advised.

[Local anesthesia in children: standard and limits]

The use of local anesthetics is known to be safe and efficient in surgical and dental treatments. Local anesthetics are essential in dentistry for appropriate pain control as they inhibit nociception generated during surgical and dental procedures. However, among other precautions, attention has to be paid to the individual maximum dose of the local anesthetics that is administered. This is especially important for children who are, due to their low body weight, more prone to adverse events following substance overdose. Therefore, this contribution gives advice for general dentists on the accurate use and maximum dose of local anesthetics in children.

[Application of tranexamic acid within the field of dentistry]

The antifibrinolytic agent tranexamic acid (TXA) is well known for its capacity to effectively reduce intraoperative blood loss. The effect mechanism of TXA is based on the indirect inhibition of fibrin degradation, whereby existing blood clots within the surgical area are stabilized. Consecutively, the amount of blood loss can be reduced. Due to its great efficacy to minimize blood loss and its low rate of unintended side effects, TXA is regularly used in different surgical fields. Within the field of dentistry TXA is not applied on a regular basis, however, it presents a highly effective and convenient treatment option to reduce bleeding complications.

Concordance of tumor infiltrating lymphocytes, PD-L1 and p16 expression in small biopsies, resection and lymph node metastases of oropharyngeal squamous cell carcinoma

OBJECTIVE

The incidence of oropharyngeal squamous cell carcinoma (OPSCC), especially human papillomavirus (HPV)-associated, is increasing worldwide. Immunotherapy become available for patients with carcinomas in the head and neck region, however without ideal biomarker. Markers like PD-L1 vary in the clone of the antibody used, and the method of evaluation. Adequate and reliable immune cells characterization and evaluation is still not found. Furthermore, studies analyzing representativeness of different tissue samples are scarce. We analyzed small biopsy, lymph node (LN) metastasis and resected OPSCC, in regards of tumor infiltrating lymphocyte (TIL) density, PD-L1 and p16 expression.

MATERIAL AND METHODS

Patients with OPSCC diagnosed from 2000 to 2016, with small biopsy, resection specimen and LN metastasis samples were selected. We analyzed TILs on hematoxylin-eosin stain, and PD-L1 and p16 expression in tumor cells. Concordance between different tumor locations was evaluated.

RESULTS

93 patients, with 65 small biopsies, 72 resection specimens, and 70 LN metastases were included. TILs, p16 and PD-L1 demonstrated very high concordance. Additionally, PD-L1 expression in the small biopsies was more representative of the PD-L1 expression in the resection specimens, than the LN samples.

CONCLUSION

TILs density can be reliably assessed using hematoxylin-eosin stain with high concordance between the small biopsy, resection specimen and LN metastasis. Evaluation of concordance of p16 expression is very high, nevertheless some cases might be misdiagnosed on a small biopsy or lymph node metastasis. Evaluation of PD-L1 expression is very reliable on the biopsy specimen. Different PD-L1 clones and methods of evaluation still remain to be addressed.

Clinical evaluation of semi-automatic open-source algorithmic software segmentation of the mandibular bone: Practical feasibility and assessment of a new course of action

INTRODUCTION

Computer assisted technologies based on algorithmic software segmentation are an increasing topic of interest in complex surgical cases. However-due to functional instability, time consuming software processes, personnel resources or licensed-based financial costs many segmentation processes are often outsourced from clinical centers to third parties and the industry. Therefore, the aim of this trial was to assess the practical feasibility of an easy available, functional stable and licensed-free segmentation approach to be used in the clinical practice.

MATERIAL AND METHODS

In this retrospective, randomized, controlled trail the accuracy and accordance of the open-source based segmentation algorithm GrowCut was assessed through the comparison to the manually generated ground truth of the same anatomy using 10 CT lower jaw data-sets from the clinical routine. Assessment parameters were the segmentation time, the volume, the voxel number, the Dice Score and the Hausdorff distance.

RESULTS

Overall semi-automatic GrowCut segmentation times were about one minute. Mean Dice Score values of over 85% and Hausdorff Distances below 33.5 voxel could be achieved between the algorithmic GrowCut-based segmentations and the manual generated ground truth schemes. Statistical differences between the assessment parameters were not significant (p<0.05) and correlation coefficients were close to the value one (r > 0.94) for any of the comparison made between the two groups.

DISCUSSION

Complete functional stable and time saving segmentations with high accuracy and high positive correlation could be performed by the presented interactive open-source based approach. In the cranio-maxillofacial complex the used method could represent an algorithmic alternative for image-based segmentation in the clinical practice for e.g. surgical treatment planning or visualization of postoperative results and offers several advantages. Due to an open-source basis the used method could be further developed by other groups or specialists. Systematic comparisons to other segmentation approaches or with a greater data amount are areas of future works.

The Nasopalatine Canal in Adults on Cone Beam Computed Tomograms-A Clinical Study and Review of the Literature

AIM

The aims of this study were to assess the location, morphology and anatomical dimensions of the nasopalatine canal (NPC) on cone beam computed tomographic (CBCT) images and to compare our findings with recent reports on this matter. A detailed knowledge of anatomical variations is mandatory in skeletal surgery of the anterior maxilla.

PATIENTS AND METHODS

Two hundred CBCT scans of the mid-facial region were analyzed from adult patients at the Outpatient Clinic of the Department of Oral and Craniomaxillofacial Surgery, University of Hamburg, Germany. Patients were scanned using standard exposure time at normal patient positioning inside the CBCT device. Three-dimensional (3D) CBCT images were carefully analyzed regarding NPC location, morphology and anatomical dimensions, and variations of radiological morphology, with respect to age and gender.

RESULTS

In the sagittal plane, the NPC typically appeared as a canal with a mean length±standard deviation (SD) of 11.15±2.87 mm. The oral cavity opening of the canal is the incisive foramen, with a mean diameter of 4.49±1.71 mm. At the entrance to the nasal floor, in most cases, two apertures were found (Y-canal morphology), but also three or four openings were observed. In particular cases, the canal presented a cylindrical aperture with only one exit to the nasal floor. The average width of the NPC at the level of the nasal floor was 3.43±1.54 mm. The labiopalatal width of the NPC measured perpendicular to the long axis of the canal on sagittal plane was 2.48±1.33 mm. Interpretation of NPC morphology was significantly different when analyzing the images in the sagittal plane only, but the technique allowed demonstration of all aspects using the combined 2D/3D interpretation.

CONCLUSION

The NPC may exhibit important anatomical variations, both with regard to morphology and its dimensions. To avoid any potential complications during dentoalveolar surgery, careful preoperative evaluation is required. 3D imaging is recommended to determine canal topography and dimensions, and to assess the individual anterior maxilla's dimensions prior to surgical procedures, such as dental implant insertion or bone augmentation.