Oral mucosa - an examination map for confocal laser endomicroscopy within the oral cavity: an experimental clinical study.

OBJECTIVES: Confocal laser endomicroscopy (CLE) is an optical method that enables microscopic visualization of oral mucosa. Previous studies have shown that it is possible to differentiate between physiological and malignant oral mucosa. However, differences in mucosal architecture were not taken into account. The objective was to map the different oral mucosal morphologies and to establish a "CLE map" of physiological mucosa as baseline for further application of this powerful technology. MATERIALS AND METHODS: The CLE database consisted of 27 patients. The following spots were examined: (1) upper lip (intraoral) (2) alveolar ridge (3) lateral tongue (4) floor of the mouth (5) hard palate (6) intercalary line. All sequences were examined by two CLE experts for morphological differences and video quality. RESULTS: Analysis revealed clear differences in image quality and possibility of depicting tissue morphologies between the various localizations of oral mucosa: imaging of the alveolar ridge and hard palate showed visually most discriminative tissue morphology. Labial mucosa was also visualized well using CLE. Here, typical morphological features such as uniform cells with regular intercellular gaps and vessels could be clearly depicted. Image generation and evaluation was particularly difficult in the area of the buccal mucosa, the lateral tongue and the floor of the mouth. CONCLUSION: A physiological "CLE map" for the entire oral cavity could be created for the first time. CLINICAL RELEVANCE: This will make it possible to take into account the existing physiological morphological features when differentiating between normal mucosa and oral squamous cell carcinoma in future work.

Raman difference spectroscopy and U-Net convolutional neural network for molecular analysis of cutaneous neurofibroma.

In Neurofibromatosis type 1 (NF1), peripheral nerve sheaths tumors are common, with cutaneous neurofibromas resulting in significant aesthetic, painful and functional problems requiring surgical removal. To date, determination of adequate surgical resection margins-complete tumor removal while attempting to preserve viable tissue-remains largely subjective. Thus, residual tumor extension beyond surgical margins or recurrence of the disease may frequently be observed. Here, we introduce Shifted-Excitation Raman Spectroscopy in combination with deep neural networks for the future perspective of objective, real-time diagnosis, and guided surgical ablation. The obtained results are validated through established histological methods. In this study, we evaluated the discrimination between cutaneous neurofibroma (n = 9) and adjacent physiological tissues (n = 25) in 34 surgical pathological specimens ex vivo at a total of 82 distinct measurement loci. Based on a convolutional neural network (U-Net), the mean raw Raman spectra (n = 8,200) were processed and refined, and afterwards the spectral peaks were assigned to their respective molecular origin. Principal component and linear discriminant analysis was used to discriminate cutaneous neurofibromas from physiological tissues with a sensitivity of 100%, specificity of 97.3%, and overall classification accuracy of 97.6%. The results enable the presented optical, non-invasive technique in combination with artificial intelligence as a promising candidate to ameliorate both, diagnosis and treatment of patients affected by cutaneous neurofibroma and NF1.

Polyphosphate-loaded silk fibroin membrane as hemostatic agent in oral surgery: a pilot study.

PURPOSE: Post-interventional hemorrhage can result in serious complications, especially in patients with hemostatic disorders. Identification of safe and efficient local hemostatic agents is important, particularly in the context of an ageing society and the emergence of new oral anticoagulants. The aim of this in vitro study was to investigate the potential of silk fibroin membranes coated with the inorganic polymer polyphosphate (polyP) as a novel hemostatic device in oral surgery. METHODS: Cocoons of the silkworm Bombyx mori were degummed and dissolved. Varying amounts of long-chain polyP (2-2000 µg/mm2) were adsorbed to the surface of silk fibroin membranes. Analysis of the procoagulant effect of polyP-coated silk membranes was performed using real-time thrombin generation assays in human plasma. Increasing concentrations of polyP (0.15-500 µg/ml) served as a positive control, while uncoated silk fibroin membranes were used as negative control. RESULTS: PolyP-coated silk fibroin membranes triggered coagulation when compared to plasma samples and pure silk fibroin membranes. A polyP-dose-dependent effect of thrombin generation could be found with a maximum (ETP = 1525.7 nM⋅min, peak thrombin = 310.1 nM, time to peak = 9.8 min, lag time = 7.6 min.) at 200 µg/mm2 of polymer loading on the silk fibroin membrane surface. CONCLUSIONS: In this study, it was demonstrated that silk fibroin membranes coated with polyP have the potential to act as a promising novel hemostatic device.

Layer-by-Layer Deposition of Regenerated Silk Fibroin─An Approach to the Surface Coating of Biomedical Implant Materials.

Biomaterials and coating techniques unlock major benefits for advanced medical therapies. Here, we explored layer-by-layer (LbL) deposition of silk fibroin (SF) by dip coating to deploy homogeneous films on different materials (titanium, magnesium, and polymers) frequently used for orthopedic and other bone-related implants. Titanium and magnesium specimens underwent preceding plasma electrolytic oxidation (PEO) to increase hydrophilicity. This was determined as surface properties were visualized by scanning electron microscopy and contact angle measurements as well as Fourier transform infrared spectroscopy (FTIR) analysis. Finally, biological in vitro evaluations of hemocompatibility, THP-1 cell culture, and TNF-α assays were conducted. A more hydrophilic surface could be achieved using the PEO surface, and the contact angle for magnesium and titanium showed a reduction from 73 to 18° and from 58 to 17°, respectively. Coating with SF proved successful on all three surfaces, and coating thicknesses of up to 5.14 µm (±SD 0.22 µm) were achieved. Using FTIR analysis, it was shown that the insolubility of the material was achieved by post-treatment with water vapor annealing, although the random coil peak (1640-1649 cm-1) and the α-helix peak (at 1650 cm-1) were still evident. SF did not change hemocompatibility, regardless of the substrate, whereas the PEO-coated materials showed improved hemocompatibility. THP-1 cell culture showed that cells adhered excellently to all of the tested material surfaces. Interestingly, SF coatings induced a significantly higher amount of TNF-α for all materials, indicating an inflammatory response, which plays an important role in a variety of physiological processes, including osteogenesis. LbL coatings of SF are shown to be promising candidates to modulate the body's immune response to implants manufactured from titanium, magnesium, and polymers. They may therefore facilitate future applications for bioactive implant coatings. However, further in vivo studies are needed to confirm the proposed effects on osteogenesis in a physiological environment.

Raman spectroscopy and U-Net deep neural network in antiresorptive drug-related osteonecrosis of the jaw.

OBJECTIVE: Application of an optical method for the identification of antiresorptive drug-related osteonecrosis of the jaw (ARONJ). METHODS: We introduce shifted-excitation Raman difference spectroscopy followed by U-Net deep neural network refinement to determine bone tissue viability. The obtained results are validated through established histological methods. RESULTS: Discrimination of osteonecrosis from physiological tissues was evaluated at 119 distinct measurement loci in 40 surgical specimens from 28 patients. Mean Raman spectra were refined from 11,900 raw spectra, and characteristic peaks were assigned to their respective molecular origin. Then, following principal component and linear discriminant analyses, osteonecrotic lesions were distinguished from physiological tissue entities, such as viable bone, with a sensitivity, specificity, and overall accuracy of 100%. Moreover, bone mineral content, quality, maturity, and crystallinity were quantified, revealing an increased mineral-to-matrix ratio and decreased carbonate-to-phosphate ratio in ARONJ lesions compared to physiological bone. CONCLUSION: The results demonstrate feasibility with high classification accuracy in this collective. The differentiation was determined by the spectral features of the organic and mineral composition of bone. This merely optical, noninvasive technique is a promising candidate to ameliorate both the diagnosis and treatment of ARONJ in the future.

Horizontal augmentation techniques in the mandible: a systematic review.

PURPOSE: Placement of dental implants has evolved to be an advantageous treatment option for rehabilitation of the fully or partially edentulous mandible. In case of extensive horizontal bone resorption, the bone volume needs to be augmented prior to or during implant placement in order to obtain dental rehabilitation and maximize implant survival and success. METHODS: Our aim was to systematically review the available data on lateral augmentation techniques in the horizontally compromised mandible considering all grafting protocols using xenogeneic, synthetic, or allogeneic material. A computerized and manual literature search was performed for clinical studies (published January 1995 to March 2021). RESULTS: Eight studies ultimately met the inclusion criteria comprising a total of 276 procedures of xenogeneic, allogeneic, or autogenous bone graft applications in horizontal ridge defects. Particulate materials as well as bone blocks were used as grafts with a mean follow-up of 26.0 months across all included studies. Outcome measures, approaches and materials varied from study to study. A gain of horizontal bone width of the mandible with a mean of 4.8 mm was observed in seven of eight studies. All but one study, reported low bone graft failure rates of 4.4% in average. CONCLUSIONS: Only limited data are available on the impact of different horizontal augmentation strategies in the mandible. The results show outcomes for xenogeneic as well as autologous bone materials for horizontal ridge augmentation of the lower jaw. The use of allogeneic bone-block grafts in combination with resorbable barrier membranes must be re-evaluated. Randomized controlled clinical trials are largely missing.

COVID-19-associated Parotid Gland Abscess.

BACKGROUND: Human infection with the SARS-CoV-2 virus has caused a pandemic characterized by a plethora of diseases, of which those affecting the internal organs and nervous system can have severe, life-threatening consequences. Among the manifestations of the disease at the viral entry site, diseases in oral mucosa adnexa are rarely reported. This case report describes a COVID-19-associated aggravating parotid gland disease. CASE REPORT: The 47-year-old, SARS-CoV-2-positive male patient, already hospitalized and now in need of ventilation, had been referred for intensive care treatment due to increasing respiratory problems. A unilateral swelling of the cheek was noticed, the cause of which was initially a parotid gland infection. Examination ruled out mechanical causes of the parotid gland. During further treatment, the patient developed a parotid abscess, which was drained extra orally. CONCLUSION: The oral cavity is primarily considered as a reservoir of the pathogen. There is an increasing number of reports detailing inflammation of the major salivary glands associated with SARS-CoV-2 virus. Knowledge of this association facilitates therapeutic decisions.

Optical diagnosis of oral cavity lesions by label-free Raman spectroscopy.

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers and frequently preceded by non-malignant lesions. Using Shifted-Excitation Raman Difference Spectroscopy (SERDS), principal component and linear discriminant analysis in native tissue specimens, 9500 raw Raman spectra of OSCC, 4300 of non-malignant lesions and 4200 of physiological mucosa were evaluated. Non-malignant lesions were distinguished from physiological mucosa with a classification accuracy of 95.3% (95.4% sensitivity, 95.2% specificity, area under the curve (AUC) 0.99). Discriminating OSCC from non-malignant lesions showed an accuracy of 88.4% (93.7% sensitivity, 76.7% specificity, AUC 0.93). OSCC was identified against physiological mucosa with an accuracy of 89.8% (93.7% sensitivity, 81.0% specificity, AUC 0.90). These findings underline the potential of SERDS for the diagnosis of oral cavity lesions.

Toward Tailoring the Degradation Rate of Magnesium-Based Biomaterials for Various Medical Applications: Assessing Corrosion, Cytocompatibility and Immunological Effects.

Magnesium (Mg)-based biomaterials hold considerable promise for applications in regenerative medicine. However, the degradation of Mg needs to be reduced to control toxicity caused by its rapid natural corrosion. In the process of developing new Mg alloys with various surface modifications, an efficient assessment of the relevant properties is essential. In the present study, a WE43 Mg alloy with a plasma electrolytic oxidation (PEO)-generated surface was investigated. Surface microstructure, hydrogen gas evolution in immersion tests and cytocompatibility were assessed. In addition, a novel in vitro immunological test using primary human lymphocytes was introduced. On PEO-treated WE43, a larger number of pores and microcracks, as well as increased roughness, were observed compared to untreated WE43. Hydrogen gas evolution after two weeks was reduced by 40.7% through PEO treatment, indicating a significantly reduced corrosion rate. In contrast to untreated WE43, PEO-treated WE43 exhibited excellent cytocompatibility. After incubation for three days, untreated WE43 killed over 90% of lymphocytes while more than 80% of the cells were still vital after incubation with the PEO-treated WE43. PEO-treated WE43 slightly stimulated the activation, proliferation and toxin (perforin and granzyme B) expression of CD8+ T cells. This study demonstrates that the combined assessment of corrosion, cytocompatibility and immunological effects on primary human lymphocytes provide a comprehensive and effective procedure for characterizing Mg variants with tailorable degradation and other features. PEO-treated WE43 is a promising candidate for further development as a degradable biomaterial.

A meta-analysis of the pros and cons of partial superficial parotidectomy versus superficial parotidectomy for the treatment of benign parotid neoplasms.

OBJECTIVES: Salivary gland tumors are predominantly benign and frequently localized in the parotid gland (P). The treatment consists primarily of surgical removal; however, the appropriate extent remains a subject of debate. In suitable tumors, superficial parotidectomy (SP) may be substituted for less invasive partial superficial parotidectomy (PSP) (I C). This systematic review analyzed the available literature, comparing PSP and SP with regards to several postoperative outcome parameters (O). MATERIALS AND METHODS: Established medical databanks were screened for articles evaluating outcomes of PSP compared with SP, published between 1955 and 2019. These data were assessed by pooled risk and odds ratios via meta-analysis. RESULTS: 11 studies with 1272 patients were included. There was no significant difference in tumor recurrence between PSP and SP (primary outcome). Furthermore, no differences in the occurrence of permanent facial nerve paralysis (FNP), salivary fistula, great auricular nerve analgesia, or hematoma were observed between the groups. However, PSP displayed significantly reduced rates of transient FNP, Frey's syndrome, scar deformity, and xerostomia, as well as shorter surgical time, compared with SP (secondary outcomes). CONCLUSION: Based on these data, PSP can be recommended as a surgical technique for the treatment of superficially located, small, benign parotid tumors.

Association of Online Learning Behavior and Learning Outcomes for Medical Students: Large-Scale Usage Data Analysis.

BACKGROUND: Digital learning environments have become very common in the training of medical professionals, and students often use such platforms for exam preparation. Multiple choice questions (MCQs) are a common format in medical exams and are used by students to prepare for said exams. OBJECTIVE: We aimed to examine whether particular learning activities contributed more strongly than others to users' exam performance. METHODS: We analyzed data from users of an online platform that provides learning materials for medical students in preparation for their final exams. We analyzed whether the number of learning cards viewed and the number of MCQs taken were positively related to learning outcomes. We also examined whether viewing learning cards or answering MCQs was more effective. Finally, we tested whether taking individual notes predicted learning outcomes, and whether taking notes had an effect after controlling for the effects of learning cards and MCQs. Our analyses from the online platform Amboss are based on user activity data, which supplied the number of learning cards studied and test questions answered. We also included the number of notes from each of those 23,633 users who had studied at least 200 learning cards and had answered at least 1000 test exam questions in the 180 days before their state exam. The activity data for this analysis was collected retrospectively, using Amboss archival usage data from April 2014 to April 2017. Learning outcomes were measured using the final state exam scores that were calculated by using the answers voluntarily entered by the participants. RESULTS: We found correlations between the number of cards studied (r=.22; P<.001) and the number of test questions that had been answered (r=.23; P<.001) with the percentage of correct answers in the learners' medical exams. The number of test questions answered still yielded a significant effect, even after controlling for the number of learning cards studied using a hierarchical regression analysis (ß=.14; P<.001; ΔR2=.017; P<.001). We found a negative interaction between the number of learning cards and MCQs, indicating that users with high scores for learning cards and MCQs had the highest exam scores. Those 8040 participants who had taken at least one note had a higher percentage of correct answers (80.94%; SD=7.44) than those who had not taken any notes (78.73%; SD=7.80; t23631=20.95; P<.001). In a stepwise regression, the number of notes the participants had taken predicted the percentage of correct answers over and above the effect of the number of learning cards studied and of the number of test questions entered in step one (ß=.06; P<.001; ΔR2=.004; P<.001). CONCLUSIONS: These results show that online learning platforms are particularly helpful whenever learners engage in active elaboration in learning material, such as by answering MCQs or taking notes.

Perioperative Management in Patients With Undergoing Direct Oral Anticoagulant Therapy in Oral Surgery - A Multicentric Questionnaire Survey.

AIM: The purpose of this study was to survey the current opinions of hospitals and medical practices concerning the perioperative management of patients undergoing direct oral anticoagulant therapy (DOAC) and discuss recommendations for the clinical practice. MATERIALS AND METHODS: A questionnaire with 13 topics and multiple ordinal-polytomous subitems was designed and sent to 120 Departments of Oral and Maxillofacial Surgery in Austria, Switzerland and Germany, as well as to 85 oral and maxillofacial/oral surgeons in medical offices in Hamburg, Germany. The data were statistically evaluated by Chi-square, Fisher's exact and Jonckheere-Terpstra tests. RESULTS: The rate of response was 42%. Thirty-seven percent of respondents reported treating over 50 patients per year with undergoing DOAC therapy and only 18% assess a high bleeding risk [33% for vitamin K antagonists (VKA)]. In contrast to that, 62% of respondents would interrupt the DOAC therapy for extraction of one tooth, while 94% would continue VKA therapy. Significantly more clinicians apply suture than those in a medical office. The use of additional hemostatic measures varied between clinic and medical practice. There was a clear request for more detailed guidelines. CONCLUSION: The study shows the current opinion for perioperative management of patients undergoing DOAC therapy. Multi-centric studies under controlled conditions are needed for a safer treatment of anticoagulated patients as therapy strategies differ greatly between institutions and therefore a complication analysis is hardly possible.

Speech intelligibility in patients with oral cancer: An objective baseline evaluation of pretreatment function and impairment.

BACKGROUND: This study seeks to identify those factors that influence the pre-therapeutic speech intelligibility in patients with oral squamous cell carcinoma (OSCC). METHOD: A group of 172 patients (125 males, 47 females, mean age = 61 ± 11 a) with different OSCC stages ranging from T1 to T4 and N0 to N2 was examined for their speech intelligibility using a computerized measuring tool, and compared to a healthy reference group (30 males, 10 females, mean age = 59 ± 12 a). RESULTS: It was found that the pre-therapeutic speech intelligibility in patients with OSCC is decreased when compared to a healthy collective. Two demographic factors that influence speech intelligibility could be identified: sex and age. It was determined that the only disease-related factor that influences speech intelligibility before therapy is the location of the tumor. CONCLUSION: The results of this study reveal that a preoperative speech intelligibility impairment in patients suffering from OSCC occurs independent of tumor stage, size of the tumor and infiltration status.

Osteoid Osteoma of the Mandible - Clinical and Histological Findings.

BACKGROUND/AIM: Osteoid osteoma (OO) is a benign tumor characterized by the excessive formation of unmineralized bone matrix. It is mostly located in the long bones of the lower extremities or the spine, but can also occur in atypical locations. PATIENTS AND METHODS: Here we report on a rare case of OO in the mandible in an 18-year-old male patient with a simultaneous finding of a pilomatrixoma in the parietal region. Initially, a biopsy had been taken due to an unclear tumor mass and non-specific pain adjacent to tooth 46. RESULTS: The detailed radiographic and histopathological analysis revealed the diagnosis of OO in terms of a characteristic radiolucent nidus and structurally disorganized woven bone with osteoid, respectively. The tumor was subsequently completely resected resulting in a complete recovery of symptoms. CONCLUSION: As we demonstrate an infrequent finding of OO in the mandible, it is important to diagnose and treat this condition appropriately.

Deep learning-based detection of motion artifacts in probe-based confocal laser endomicroscopy images.

PURPOSE: Probe-based confocal laser endomicroscopy (pCLE) is a subcellular in vivo imaging technique capable of producing images that enable diagnosis of malign structural modifications in epithelial tissue. Images acquired with pCLE are, however, often tainted by significant artifacts that impair diagnosis. This is especially detrimental for automated image analysis, which is why said images are often excluded from recognition pipelines. METHODS: We present an approach for the automatic detection of motion artifacts in pCLE images and apply this methodology to a data set of 15 thousand images of epithelial tissue acquired in the oral cavity and the vocal folds. The approach is based on transfer learning from intermediate endpoints within a pre-trained Inception v3 network with tailored preprocessing. For detection within the non-rectangular pCLE images, we perform pooling within the activation maps of the network and evaluate this at different network depths. RESULTS: We achieved area under the ROC curve values of 0.92 with the proposed method, compared to 0.80 for the best feature-based machine learning approach. Our overall accuracy with the presented approach is 94.8%. CONCLUSION: Over traditional machine learning approaches with state-of-the-art features, we achieved significantly improved overall performance.

Local anaesthesia training for undergraduate students - how big is the step from model to man?

BACKGROUND: Local anesthesia is an important skill and a prerequisite for most dental treatments. However, the step from theory to application on the patient is huge for the novice. Hence, a mannequin training model course was developed and implemented into the existing local anesthesia curriculum in undergraduate dental students. It was the aim of this study to evaluate the relation between training-model and real-life anesthesia performance and to measure whether a gain in skill on the model translates to the actual patient situation. METHODS: Thirty-six third-year students (14 males, 22 females, age 24 years±2.98) attended the four-day course comprising each 4 h of lectures and practical training. The student cohort gave subjective ratings about the didactical components of the course after attendance by using the TRIL questionnaire (TRIL-mod; University of Trier). At the end of the course the performance of each student in administering an inferior alveolar nerve (IAN) block on the training model as well as on a fellow dental student was investigated using a standardized checklist. To evaluate the successful performance, the in vivo IAN-block was assessed using subjective patient-feeling, the sharp-blunt test and an objective pain- and thermal sensitivity tester (PATH). RESULTS: The course was rated with an average score of 5.25 ± 0.44 (range 1-6; 6 = best). On the training model, 69.4% of the students successfully performed an IAN-block. The in vivo assessment, objectified by the PATH test, showed a successful anesthesia in 36.9% of the cases. The assessment of local anesthesia by using the sharp blunt test and the subjective patient feeling significantly correlated with these findings (k = 0.453-0.751, p < 0.05). The model performance did not correlate with the performance on the patient (k = 0.137, p = 0.198). CONCLUSIONS: Although subjective ratings of the course were high, the anesthesia success rate on mannequin models did not imply an equal performance on the in vivo setting. As local anesthesia training models are a valuable didactic complement, the focus of the training should be on to the actual real life situation. Chair side feedback should be offered to the students using one of the presented evaluation methods.

Plasma Electrolytic Oxidation of Titanium Implant Surfaces: Microgroove-Structures Improve Cellular Adhesion and Viability.

BACKGROUND/AIM: Plasma electrolytic oxidation (PEO) is an established electrochemical treatment technique that can be used for surface modifications of metal implants. In this study we to treated titanium implants with PEO, to examine the resulting microstructure and to characterize adhesion and viability of cells on the treated surfaces. Our aim was to identify an optimal surface-modification for titanium implants in order to improve soft-tissue integration. MATERIALS AND METHODS: Three surface-variants were generated on titanium alloy Ti6Al4V by PEO-treatment. The elemental composition and the microstructures of the surfaces were characterized using energy dispersive X-ray spectroscopy, scanning electron microscopy and profilometry. In vitro cytocompatibility of the surfaces was assessed by seeding L929 fibroblasts onto them and measuring the adhesion, viability and cytotoxicity of cells by means of live/dead staining, XTT assay and LDH assay. RESULTS: Electron microscopy and profilometry revealed that the PEO-surface variants differed largely in microstructure/topography, porosity and roughness from the untreated control material as well as from one another. Roughness was generally increased after PEO-treatment. In vitro, PEO-treatment led to improved cellular adhesion and viability of cells accompanied by decreased cytotoxicity. CONCLUSION: PEO-treatment provides a promising strategy to improve the integration of titanium implants with surrounding tissues.

Automatic Classification of Cancerous Tissue in Laserendomicroscopy Images of the Oral Cavity using Deep Learning.

Oral Squamous Cell Carcinoma (OSCC) is a common type of cancer of the oral epithelium. Despite their high impact on mortality, sufficient screening methods for early diagnosis of OSCC often lack accuracy and thus OSCCs are mostly diagnosed at a late stage. Early detection and accurate outline estimation of OSCCs would lead to a better curative outcome and a reduction in recurrence rates after surgical treatment. Confocal Laser Endomicroscopy (CLE) records sub-surface micro-anatomical images for in vivo cell structure analysis. Recent CLE studies showed great prospects for a reliable, real-time ultrastructural imaging of OSCC in situ. We present and evaluate a novel automatic approach for OSCC diagnosis using deep learning technologies on CLE images. The method is compared against textural feature-based machine learning approaches that represent the current state of the art. For this work, CLE image sequences (7894 images) from patients diagnosed with OSCC were obtained from 4 specific locations in the oral cavity, including the OSCC lesion. The present approach is found to outperform the state of the art in CLE image recognition with an area under the curve (AUC) of 0.96 and a mean accuracy of 88.3% (sensitivity 86.6%, specificity 90%).

Long-term Outcome of Speech Intelligibility in Maxillary Dental Rehabilitation with Full Dentures: A Prospective Study Using Automatic Speech Quantification.

AIMS: Complete maxillary edentulism and prosthetic rehabilitation with removable full dentures are known to affect speech intelligibility. The aim of this study was to prospectively investigate the long-term effect of time on speech intelligibility in patients being rehabilitated with newly fabricated full maxillary dentures. MATERIALS AND METHODS: Speech was recorded in a group of 14 patients (male = 9, female = 5; mean age ± standard deviation [SD] = 66.14 ± 7.03 years) five times within a mean period of 4 years (mean ± SD: 47.50 ± 18.16 months; minimum/maximum: 24/68 months) and in a control group of 40 persons with healthy dentition (male = 30, female = 10; mean age ± SD = 59 ± 12 years). All 14 participants had their inadequate removable full maxillary dentures replaced with newly fabricated dentures. Speech intelligibility was measured by means of a polyphone-based speech recognition system that automatically computed the percentage of accurately spoken words (word accuracy [WA]) at five different points in time: 1 week prior to prosthetic maxillary rehabilitation (both with and without inadequate dentures in situ) and at 1 week, 6 months, and a mean of 48 months after the insertion of newly fabricated full maxillary dentures. RESULTS: Speech intelligibility of the patients significantly improved after 6 months of adaptation to the new removable full maxillary dentures (WA = 66.93% ± 9.21%) compared to inadequate dentures in situ (WA = 60.12% ± 10.48%). After this period, no further significant change in speech intelligibility was observed. After 1 week of adaptation, speech intelligibility of the rehabilitated patients aligned with that of the control group (WA = 69.79% ± 10.60%) and remained at this level during the examination period of 48 months. CONCLUSION: The provision of new removable full maxillary dentures can improve speech intelligibility to the level of a healthy control group on a long-term basis.

Autofluorescence spectroscopy for nerve-sparing laser surgery of the head and neck-the influence of laser-tissue interaction.

The use of remote optical feedback systems represents a promising approach for minimally invasive, nerve-sparing laser surgery. Autofluorescence properties can be exploited for a fast, robust identification of nervous tissue. With regard to the crucial step towards clinical application, the impact of laser ablation on optical properties in the vicinity of structures of the head and neck has not been investigated up to now. We acquired 24,298 autofluorescence spectra from 135 tissue samples (nine ex vivo tissue types from 15 bisected pig heads) both before and after ER:YAG laser ablation. Sensitivities, specificities, and area under curve(AUC) values for each tissue pair as well as the confusion matrix were statistically calculated for pre-ablation and post-ablation autofluorescence spectra using principal component analysis (PCA), quadratic discriminant analysis (QDA), and receiver operating characteristics (ROC). The confusion matrix indicated a highly successful tissue discrimination rate before laser exposure, with an average classification error of 5.2%. The clinically relevant tissue pairs nerve/cancellous bone and nerve/salivary gland yielded an AUC of 100% each. After laser ablation, tissue discrimination was feasible with an average classification accuracy of 92.1% (average classification error 7.9%). The identification of nerve versus cancellous bone and salivary gland performed very well with an AUC of 100 and 99%, respectively. Nerve-sparing laser surgery in the area of the head and neck by means of an autofluorescence-based feedback system is feasible even after ER-YAG laser-tissue interactions. These results represent a crucial step for the development of a clinically applicable feedback tool for laser surgery interventions in the oral and maxillofacial region.