The impact and opportunities of large language models like ChatGPT in oral and maxillofacial surgery: a narrative review.

Since its release at the end of 2022, the social response to ChatGPT, a large language model (LLM), has been huge, as it has revolutionized the way we communicate with computers. This review was performed to describe the technical background of LLMs and to provide a review of the current literature on LLMs in the field of oral and maxillofacial surgery (OMS). The PubMed, Scopus, and Web of Science databases were searched for LLMs and OMS. Adjacent surgical disciplines were included to cover the entire literature, and records from Google Scholar and medRxiv were added. Out of the 57 records identified, 37 were included; 31 (84%) were related to GPT-3.5, four (11%) to GPT-4, and two (5%) to both. Current research on LLMs is mainly limited to research and scientific writing, patient information/communication, and medical education. Classic OMS diseases are underrepresented. The current literature related to LLMs in OMS has a limited evidence level. There is a need to investigate the use of LLMs scientifically and systematically in the core areas of OMS. Although LLMs are likely to add value outside the operating room, the use of LLMs raises ethical and medical regulatory issues that must first be addressed.

Immune checkpoint analysis in ear cancer.

BACKGROUND: Among cutaneous squamous cell carcinomas, the ear (ecSCC) is one of the most common sites. Loco regional lymph node metastasis is found in six to eleven percent of cases, corresponding to increased metastasis compared to other sites. The aim of this study was to test the markers PD-L1, PD-1, CD4, CD8, and FoxP3 for suitability as prognostic predictive markers. METHODS: Sixty-four patients with ecSCC were included in this study. The expression of immunohistochemical markers (PD-L1, PD-1, CD4, CD8, FOXP3) was correlated with retrospective clinic pathological parameters (lymph node metastasis, distant metastasis, lymph node metastasis during follow-up, disease progression, disease-specific death). RESULTS: There was a correlation between increased disease specific death and a weak Foxp3 (p = 0.003) or reduced CD8 (p = 0.04). A PD-L1 expression > 1% was found in 39.1% of patients. CONCLUSION: The investigated markers (CD4, CD8, FoxP3, PD-1, PD-L1) seem overall rather inappropriate for prognostic evaluation in ecSCC. Only the correlation of disease specific death with CD8 or FoxP3 seems to be worth testing in larger collectives.

Identification of risk factors for postoperative delirium in patients following intraoral reconstruction with microvascular free flaps: a matched-pair analysis.

Postoperative delirium (POD) following microvascular head and neck reconstruction negatively impacts patient outcomes, and only a few risk factors have been identified. The aim of this study was to identify additional risk factors for POD after intraoral reconstruction with microvascular free flaps. Data from 377 patients who underwent intraoral microvascular free flap reconstruction between 2011 and 2019 were analysed retrospectively. Preoperative, intraoperative, and postoperative variables were compared between 40 patients with POD and 40 patients without POD who were matched for previously identified risk factors (i.e., sex, age, American Society of Anesthesiologists class, preoperative arterial hypertension, tracheotomy, operation time, and blood transfusion). A multivariable regression analysis was then performed to identify risk factors associated with POD. POD occurred in 50 (13.3%) of the 377 cases studied; the median time of onset was postoperative day 2. Excessive preoperative alcohol consumption (odds ratio 9.22, 95% confidence interval 1.09-77.97; P = 0.041) and postoperative transplant revision (odds ratio 25.72, 95% confidence interval 1.26-525.43; P = 0.035) were identified as risk factors for POD. The identification of patients at high risk of POD based on these two risk factors may allow early adjustment of diagnostic and therapeutic modalities to improve outcomes and reduce healthcare costs.

Evaluation of fibrin, cyanoacrylate, and polyurethane-based tissue adhesives in sutureless vascular anastomosis: a comparative mechanical ex vivo study.

The stability of a microvascular anastomosis is an important prerequisite for successful tissue transfer. Advances in tissue adhesives are potentially opening new avenues for their use in sutureless microsurgical anastomosis, however they have not yet gained clinical acceptance. In this ex vivo study, a novel polyurethane-based adhesive (PA) was used in sutureless anastomoses and its stability compared with that of sutureless anastomoses performed with fibrin glue (FG) and a cyanoacrylate (CA). Stability was assessed using hydrostatic (15 per group) and mechanical tests (13 per group). A total of 84 chicken femoral arteries were used in this study. The time taken to create the PA and CA anastomoses was significantly faster when compared to the FG anastomoses (P < 0.001): 1.55 ± 0.14 min and 1.39 ± 0.06 min, respectively, compared to 2.03 ± 0.35 min. Both sustained significantly higher pressures (289.3 mmHg and 292.7 mmHg, respectively) than anastomoses using FG (137.3 mmHg) (P < 0.001). CA anastomoses (0.99 N; P < 0.001) and PA anastomoses (0.38 N; P = 0.009) could both withstand significantly higher longitudinal tensile forces compared to FG anastomoses (0.10 N). Considering the background of an in vitro study, the PA and CA anastomosis techniques were shown to be similar to each other and superior to FG, due to their stability and faster handling. These findings need to be validated and confirmed in further in vivo studies.

Perfusion of microvascular free flaps in head and neck reconstruction after prior neck dissection and irradiation.

Microvascular free flaps are frequently used for head and neck reconstruction after prior neck dissection (ND) and neck irradiation (RTX). The aim of this study was to investigate the influence of ND and RTX on flap perfusion as a critical factor for flap success. Overall, 392 patients reconstructed with a microvascular fasciocutaneous flap (FF) or perforator flap (PF) in the head and neck region between 2011 and 2020 were analysed retrospectively. Flap perfusion measured intraoperatively and postoperatively with the O2C tissue oxygen analysis system was compared between patients who had received neither ND nor RTX (controls), patients who had received ND but no RTX (ND group), and patients who had received both ND and RTX (ND+RTX group). Intraoperative and postoperative flap blood flow was decreased in FFs in ND group patients compared to controls (median 66.3 AU vs 86.0 AU, P = 0.023; median 73.5 AU vs 93.8 AU, P = 0.045, respectively). In the multivariable analysis, these differences showed a tendency to persist (P = 0.052 and P = 0.056). Flap success rates were similar in control patients, ND patients, and ND+RTX patients (98.7%, 94.0%, and 97.6%, respectively). Flap perfusion is not reduced in FFs and PFs in patients who have undergone ND or ND and RTX. This indicates that neck dissection and neck irradiation should not be contraindications for microvascular free flap reconstruction.

Evaluation of anterolateral thigh flap dimensions with virtual flap models.

Free flaps are commonly used for head and neck reconstruction. However, flap dimensions are still evaluated by visual and tactile assessment. The aim of this study was to enable preoperative planning of flap dimensions for soft tissue reconstruction based on clinical parameters. Computed tomography records from 230 patients dated from 2009 to 2019 were analysed retrospectively. A virtual, three-dimensional anterolateral thigh flap model was standardized, aligned to segmented leg models in two positions, and flap thicknesses and volumes were determined. Associations of flap thickness and volume with clinical parameters were evaluated, and an approximative calculation method was derived. The laterally positioned anterolateral thigh flap showed an average (interquartile range) thickness of 15.6 mm (8.7 mm) and volume of 1.5 cm3 (0.9 cm3) per cm2. The medially positioned anterolateral thigh flap showed an average (interquartile range) thickness of 16.3 mm (8.7 mm) and volume of 1.6 cm3 (0.9 cm3) per cm2. For both flap positions, leg circumference was the strongest predictor of flap thickness (ß = 0.545, P < 0.001 and ß = 0.529, P < 0.001) and flap volume (ß = 0.523, P < 0.001 and ß = 0.480, P < 0.001). Flap dimensions can be calculated based on leg circumference, and this preoperative planning of flap dimensions can help the surgeon to select the appropriate flap.

[Current developments in primary and secondary surgical treatment of midface and periorbital trauma]. / Aktuelle Entwicklungen in der chirurgischen Primär- und Sekundärversorgung von Mittelgesichts- und periorbitalen Traumata.

Fractures of the periorbita and the midface are among the most common bony facial injuries. Aesthetic and functional reconstruction is a challenge in clinical routine. This article illustrates recent developments in the primary and secondary surgical treatment of midface and periorbital trauma. Resorbable patches and films increase the anatomic reconstructive capacity and enable treatment of extensive orbital fractures. Orbital fractures with involvement of supporting key structures are advantageously reconstructed using patient-specific implants (PSI), which are fabricated by computer-assisted manufacturing techniques and positioned by intraoperative navigation. If late complications such as bulbar malposition and enophthalmos have occurred after the initial procedure, they can be addressed by overcorrective restoration of orbital volume. The use of PSI for initial fracture restoration of the midface is not yet established but may be useful in re-osteotomies of misconsolidated fragments. Extensive midface defects with significant soft tissue involvement can be reconstructed using microvascular grafts. Consecutive reconstructive procedures may include orthognathic surgery and local flap reconstruction. In summary, the integration and advancement of computer-assisted techniques now offers individualized reconstruction procedures, which may be a viable alternative to conventional implants and compression miniplates. Future developments may focus on the search for innovative biomaterials, which can be integrated into computer-aided design and manufacturing processes.

The primary stability of two dental implant systems in low-density bone.

Primary stability in low-density bone is crucial for the long-term success of implants. Tapered implants have shown particularly favourable properties under such conditions. The aim of this study was to compare the primary stability of tapered titanium and novel cylindrical zirconia dental implant systems in low-density bone. Fifty implants (25 tapered, 25 cylindrical) were placed in the anterior maxillary bone of cadavers meeting the criteria of low-density bone. The maximum insertion (ITV) and removal (RTV) torque values were recorded, and the implant stability quotients (ISQ) determined. To establish the isolated influence of cancellous bone on primary stability, the implantation procedure was performed in standardized low-density polyurethane foam bone blocks (cancellous bone model) using the same procedure. The primary stability parameters of both implant types showed significant positive correlations with bone density (Hounsfield units) and cortical thickness. In the cadaver, the cylindrical zirconia implants showed a significantly higher mean ISQ when compared to the tapered titanium implants (50.58 vs 37.26; P < 0.001). Pearson analysis showed significant positive correlations between ITV and ISQ (P = 0.016) and between RTV and ISQ (P = 0.035) for the cylindrical zirconia implants; no such correlations were observed for the tapered titanium implants. Within the limitations of this study, the results indicate that cylindrical zirconia implants represent a comparable viable treatment option to tapered titanium implants in terms of primary implant stability in low-density human bone.

Immune checkpoint analysis in lip cancer.

The aim of this study was to establish whether PD-L1, PD-1, and markers of the tumor microenvironment (CD4, CD8, FOXP3) could have a prognostic value in squamous cell carcinoma of the lip (LSCC). In patients with histologically proven LSCC, tumor specimens were stained using immunohistochemistry (for PD-1, PD-L1, CD4, CD8, and FOXP3) on paraffin-embedded tissues. Patients with (N+) and without (N-) nodal metastasis were stratified and matched to each other according to prognostically relevant clinicopathological parameters. 58 patients (29 N+ and 29 N-) were included. PD-L1 expression was positive (>1%) in 56.1% (n = 33) of all LSCC cases, but its expression did not differ significantly between metastasis groups (65.5% in N+ versus 48.3% in N-; p = 0.144). Nodal disseminated LSCC showed a tendency for higher PD-L1 expression. None of the analyzed markers showed significant correlation with the risk for nodal disease, or revealed significant prognostic value. Due to their significant expression, PD-L1 and PD-1 are potential targets for checkpoint inhibitor therapy in LSCC. Their expression should be analyzed in advanced and metastasized LSCC cases.

The effect of zirconia and titanium surfaces on biofilm formation and on host-derived immunological parameters.

The aim of this study was to analyse the effect of zirconia and titanium surfaces on biofilm formation and host-derived parameters. Studies comparing zirconia and titanium surfaces were selected up to September 1, 2019. The outcome measures were surface roughness, contact angle, bacterial count, bacterial adherence, biofilm thickness, bacterial distribution, and specifically investigated biofilm and specific host-derived immunological parameters. Random-effects meta-analyses of in vitro and in vivo studies were conducted. A total of 39 studies were included for data extraction. In the systematic review data, 10 studies stated that zirconia accumulated less initial oral biofilm parameters, 16 investigations showed negligible inter-material differences, and only one study showed that zirconia attracted the most biofilm. However, in the meta-analysis, the bacterial coverage was found to be significantly superior for zirconia surfaces (P< 0.00001); the other outcome measures did not show any statistically significant differences between zirconia and titanium for the remaining parameters and the studies presented a substantial degree of heterogeneity. Overall, on the basis of the meta-analysis, the current data situation does not allow a clear preference for the use of zirconia or titanium.

Influence of bone density, screw size and surgical procedure on orthodontic mini-implant placement - part A: temperature development.

The aim of this in vitro study was to determine the influence of bone density, orthodontic mini-implant (OMI) size, and the surgical procedure on temperature increase during implant site osteotomy and placement. OMIs of different sizes (2.0×7, 2.3×7, 2.0×11, and 2.3×11mm) were placed in artificial bone blocks of different densities (D1-D4). Optionally, the drilling and insertion angle was 90° or 60° to the bone surface. A total of 640 OMIs were inserted, and predrilling was performed in 320 cases. All insertions were done without irrigation with an axial load of 20N, which resulted in 64 groups. Temperature measurements were performed during implant site preparation and placement using Type-K-thermocouples. Mean temperature increase differed for OMI osteotomy between 1.38°C and 8.75°C and placement between 3.8°C and 18.74°C, respectively. Critical thermal increase was especially reached during placement using long implants. Increasing bone density and implant size (diameter

Influence of bone density, screw size and surgical procedure on orthodontic mini-implant placement - part B: implant stability.

This in vitro study aimed to investigate the influence of bone density, implant size, and surgical procedure on the primary stability (PS) of orthodontic mini-implants (OMIs). In total, 640 OMIs of various sizes (2.0 × 7, 2.3 × 7, 2.0 × 11 and 2.3 × 11 mm) were inserted in the artificial bone of different densities (D1-D4). Placement was performed with an insertion angle of 90° or 60° to the bone surface and in 320 cases without predrilling, which resulted in 64 groups. PS was measured on the basis of implant stability quotient (ISQ) and insertion torque (IT). With regard to all possible influencing parameters, the mean PS differed between 39.20 and 60.00 (ISQ), and 10.00 and 39.00 Ncm (IT). The effect of OMI size and surgical procedure was dependent on bone quality. For example, implant size had less effect in high-density bone and was stronger with decreasing density. Overall, implant length had a greater influence than the diameter, and a high correlation was found among both PS measurement techniques. Therefore, a suitable choice of implant size and surgical protocol with regard to bone density can positively influence PS. In principle, ISQ and IT are suitable for measuring OMI stability.

Changes in the temporomandibular joint position depending on the sagittal osteotomy technique and extent of mandibular movement.

The bilateral sagittal split osteotomy (BSSO) and high oblique sagittal split osteotomy (HSSO) are common techniques for mandibular movement in orthognathic surgery. The aim of this study was to evaluate the influence of both techniques, as well as movement distances and directions, on the position of the temporomandibular joint (TMJ). A total of 80 mandibular movements were performed on 20 fresh human cadaver heads, four on each head. Pre- and postoperative cone beam computed tomography was used to plan the surgical procedure and analyse the TMJ. Reference measurements included the anterior, superior, and posterior joint spaces, intercondylar distances and angles in the axial and coronal planes, and the sagittal, coronal, and axial angulations of the proximal segment. Only minor differences were found between the BSSO and HSSO techniques, particularly in terms of the intercondylar angle in the axial plane (P < 0.03) and the condylar angle of the proximal segment in the sagittal plane (P < 0.011). Observed changes in the TMJ were mostly opposite when moving the mandible forwards and backwards and increased with increasing movement distance. BSSO and HSSO result in similar changes in TMJ position. The extent of the movement distance influences the position of the condyle more than the osteotomy technique.

Immediate dental and skeletal influence of distractor position on surgically assisted rapid palatal expansion with or without pterygomaxillary disjunction.

The outcome of surgically assisted rapid palatal expansion (SARPE) can be affected by pterygomaxillary disjunction (PMD) and the distractor position. In this study, SARPE was performed, with or without PMD, in 20 fresh cadaver heads. Transverse expansion was conducted twice using a bone-borne distractor in the anterior and posterior positions, resulting in four groups (n=10). Cone beam computed tomography scans were completed before and after SARPE to evaluate maxillary changes. A comparative anterior decrease and posterior increase in midpalatal opening resulted from SARPE with PMD combined with a posteriorly placed distractor. Significant differences in the internal transverse changes were found between the two SARPE techniques combined with an anterior distractor at the level of the premolars and molars for alveolar ridge width (P=0.040, P=0.024), and at the level of the molars for the dental crown width (P=0.017) and corresponding tooth cusp width (P=0.018). In contrast, using a posteriorly placed distractor led to a significant difference for tooth cusp width only (P=0.050). No statistically significant differences were found between external transverse changes or between distractor positions. PMD is more important in achieving a more uniform and parallel transverse expansion pattern than the distractor position. However, a posterior distractor seems to intensify the effects of PMD.

United Kingdom immigration and emigration of oral and maxillofacial Surgery (OMFS) specialists 2000-2020: how might Brexit impact on OMFS?

The United Kingdom left the European Union (EU) in January 2020. As it is unclear how many of the rights of OMFS surgeons to travel and work will remain after the transition period, we have reviewed how these rights have been used in the past. The OMFS specialist list from the GMC was compared with a database of current OMFS colleagues. Data were analysed using WinStat® (R. Fitch Software). Of 494 active surgeons on the OMFS specialist list, 23 (5%) completed their OMFS training outside the UK. Of these, 22 were specialists from Europe of whom 12 were substantive NHS consultants with others working as Fellows or visiting the UK occasionally. Two per cent of UK OMFS consultants are -specialists from Europe, the majority from Greece. Of the OMFS specialists who completed training in the UK since 1995, 24 are currently working outside the UK, and of them, 16 left the UK to return to their nation of origin (all 11 of those working in the European Economic Area [EEA] were born there). Of the seven UK-born specialists working overseas, none was working in the EEA. Twenty per cent of UK trainees whose primary degree was known (n = 117) received their primary qualification outside the UK, 38 in from the EU, and 79 from further afield. The majority of these UK trained specialists with non-UK first degrees (n = 101) stayed in the UK to work after training. The most significant impact of Brexit on OMFS could be a restriction on the opportunity for non-UK doctors and dentists to come to the UK to train and stay to work.

European OMFS in the time of Brexit - where did the UK fit and how might the future look?

INTRODUCTION: The specialty of OMFS in the UK is a dual degree specialty which was recognised in Europe within Annex V of Directive 2005/36/EU. Currently UK law matches that of the EU. Brexit may change this. DIRECTIVE 2005/36/EU: Defines two specialties within European nations, Dental, Oro-Maxillo-Facial Training DOMFS (Basic dental & medical training) and Maxillofacial Surgery (basic medical training). The UK sat within DOMFS and so specialists from DOMFS nations could travel and work in the UK. Specialists from all other nations were required to use the Certificate of Eligibility for Specialist Registration (CESR) route. DIRECTIVE 2013/55/EU: This directive updated 2005/36/EU regarding Mutually Recognised Professional Qualifications (MRPQ) including creating an international alert system for doctors in difficult Entry onto the UK OMFS Specialist List by CESR Route CESR application is a large and complex portfolio of evidence to demonstrate knowledge, skills and experience are equivalent to a Certificate of Completion of Training (CCT) holder. To date, no EU applicants have successfully completed a CESR application. UNION OF EUROPEAN MEDICAL SPECIALISTS (UEMS): Even after Brexit, the UK will remain a full member of UEMS. The OMFS Section of UEMS is a source of information and support for specialists wishing to work in other nations and for nations wishing to develop an OMFS specialty in their nation. ACCESS TO UK OMFS TRAINING FOR NON-UK TRAINEES: Applicants meeting the person specifications for approved OMFS specialty training (ST) posts in the UK are welcome to apply to the national selection process for OMFS specialty training in the UK. Many have done so successfully. Fixed term appointments and Fellowships are advertised and represent a useful route to gain support for application for training or through the CESR Route. CONCLUSIONS: The UK remains part of the diverse OMFS community in Europe. There is support from within the UK and from UEMS for trainees and specialists interested in coming to the UK to train or to work.

Evaluation of a novel osteosynthesis plate system for mandibular defects.

Continuity defects of the jaw can be reconstructed with titanium plates or microvascular bone flaps; osteosynthesis plates are necessary for both. In this study we performed a retrospective review of patients treated with Medartis MODUS® Mandible Trauma/Reco 2.0-2.5, TriLock bridging plates, mandibulectomy and soft tissue free flap or reconstruction with a bony free flap and TriLock mandibular plates from the same system from January 2015 to August 2019. The variables recorded were sex, age, diagnosis, radiotherapy, date of implantation, date of explantation or death of patient, size of mandibular defect, Jewer classification of defect, number of screws used, segments of bony reconstruction, screws per segment, plate exposure, plate breakage, and pseudarthrosis. The bridging plate group consisted of 41 patients, while the mandibular plate group consisted of 24 patients. The percentage of plate exposure was 17.07% for the bridging plate group and 4.17% for the mandibular plate group. Plate breakage was 0 in both groups. Pseudarthrosis was 4.17% in the mandibular plate group. In the bridging plate group, an anterolateral thigh flap covered all exposures. Of 7 plate exposures, 4 were found in a C defect. The complication rate of the investigated plates was lower than the complication rates of other plate systems.

Aesthetic aspects of adjacent maxillary single-crown implants-influence of zirconia and titanium as implant materials.

The purpose of this retrospective survey was to assess the esthetic aspects of adjacent zirconia and titanium implants in the anterior maxillary area. A total of 40 patients and 109 adjacent implants (17 patients with 47 titanium implants and 23 patients with 62 zirconia implants) was included. The primary aim of this survey was to assess the papillary fill (Jemt score). Additionally, further esthetic aspects were assessed. Papillae were fully present (Jemt score 3) around 39.1% of adjacent zirconia implants and 17.4% of adjacent titanium implants (p<0.01). The papilla deficit was significantly higher 1.64 mm (SD 1.35) around titanium compared to zirconia implants 0.92 mm (SD 0.94, p<0.01). The evaluation of the soft tissue recessions revealed no differences between implant materials, whereas titanium implants presented more visible implant shadows (p<0.01). Zirconia implants had more implants with papillae that filled the entire proximal space compared to titanium implants. Furthermore, titanium implants had a greater frequency of visible implant shadowing than the zirconia implants. Esthetic rules such as the interdental contact area and golden percentage rules did not differ significantly between the titanium and zirconia implants.

"Flipped OR": a modified didactical concept for a surgical clerkship in Oral and Maxillofacial Surgery.

The concept of the clerkship at the Department of Oral and Maxillofacial Surgery was modified into a modern and sustainable teaching model with a flipped classroom approach. The aim was to prove whether these changes increased the students' learning success. For the preparation of the clerkship, an e-learning module with 10 chapters was established. Students were supposed to access one chapter ahead of each day's seminar. A test to assess the gain in knowledge was undertaken before and after participation in the clerkship. An evaluation took place after the test. The results of the test after the clerkship were significantly higher than before (p<0.0001). The evaluation showed that the students were highly satisfied with the course in general, and the e-learning module specifically. In particular, the surgical videos helped them to better understand the operative steps. The clerkship at the Department of Oral and Maxillofacial Surgery was modified into a sustainable blended learning concept with a flipped classroom approach. With these developments, the "flipped operating room" was shown to be effective in improving knowledge and competence among undergraduate dental students.