BACKGROUND:3D printing has emerged as a practical method for fabricating customisable, accurate and affordable dental training models. Numerous 3D printing technologies exist, though there is no standardised comparison to inform their implementation in dental education. This study aimed to evaluate and compare the qualities of various 3D printed dental models against the current standard model used in tertiary dental education. METHODOLOGY:Five maxillary molar tooth models were fabricated using selective laser sintering (SLS), fused filament fabrication (FFF), material jetting (MJ), stereolithography (SLA) and digital light processing (DLP). A standard Ivorine tooth model (One Dental, Australia) was also evaluated. Eighteen participants performed cavity preparations and assessed each model based on haptic feedback, visual appearance, anatomical accuracy and overall suitability using a 5-point Likert scale. RESULTS:FFF was the most economical per unit ($0.06), followed by DLP ($0.30). MJ was the most expensive ($1.87), though it offers high resolution and complexity. In terms of enamel haptics and dentine haptics, MJ (3.11, 3.28), SLA (3.00, 3.33) and DLP (3.11, 3.44) were assessed as comparable to Ivorine (3.67, 3.44). Similarly, overall suitability of MJ (3.33), SLA (3.33) and DLP (3.44) was comparable to Ivorine (4.17). FFF and SLS were rated significantly inferior to Ivorine in all domains. CONCLUSIONS:Current 3D printed models do not fully simulate dental tissue and should be used to supplement the limitations of standard models and improve self-learning. Future research is warranted to develop models with improved haptic feedback and realistic surface anatomy.

Historical and contemporary subperiosteal implants continue to encounter issues with peri-implantitis, peri-implant mucositis and bacterial colonisation of the implant substructure, leading to failure of the entire implant. Combining Poly (ε-capro-lactone) (PCL) overlay scaffolds with subperiosteal implants could improve their success by encasing the implant in bone. A large animal study was undertaken with 4 groups (Titanium-only control, PCL Open, PCL Closed, and Nano PCL). Titanium subperiosteal implants were inserted with various overlying 3D printed PCL scaffold designs. Uncovered titanium was used as a control. Bony deposition was assessed at 3 months and 6 months via computed tomography, and histology at 6 months. PCL scaffolds reliably enabled bony deposition over the subperiosteal implants. A Mixed Model Analysis showed a statistically significant result both radiographically and histologically between the Titanium-only control group and the PCL Closed group, particularly surrounding the regenerated bone volumes and bone heights (maximum and mean). The PCL Open design was the next most reliable scaffold when compared against the Titanium-only group. This pilot study demonstrates that functionalised PCL scaffolds overlying subperiosteal implants can lead to bone deposition over titanium, with successful conversion into endosteal implants. PCL closed scaffold was the most effective design. This provides a basis for future clinical trials to improve the success rates of subperiosteal implants.

BACKGROUND:Heterogeneity in surgeons' and pathologists' technique poses challenges in determining a universal lymph node yield (LNY) cut-off as a quality metric for oral squamous cell carcinoma (OSCC) patients undergoing neck dissection. METHODS:OSCC patients from two head and neck centres were included. LNY cut-offs were evaluated using survival outcomes. Pathology techniques for neck dissection specimens were analyzed, comparing step serial sectioning (SSS) with inspection and palpation. RESULTS:A total of 809 patients were analyzed. Mean LNY differed significantly between centres and between pathology techniques, with SSS demonstrating the highest mean LNY. Higher LNY with SSS technique was paradoxically associated with worse survival, and reliable LNY cut-offs could not be established, while conventional pathological assessment with inspection and palpation showed greater consistency in defining LNY thresholds. CONCLUSIONS:LNY and its cut-off as a quality metric appear to be dependent on centre-specific variables. SSS appears inconsistent in determining LNY cut-off for optimal survival outcomes.

BACKGROUND:This multicenter study examines the impact of stratified surgical margins on treatment outcomes in oral SCC. METHODS:Margins were stratified into 1 mm increments from 0 to ≥ 5 mm. Outcomes included local recurrence, overall and disease-specific survivals. Sub-analyses assessed the impact of margin status by risk factors, oral subsites, and peripheral versus deep margins. RESULTS:Among 2737 patients, ≥ 2 to < 3 mm margins were associated with improved outcomes compared to 0 mm. Further benefits were observed in the ≥ 4 to < 5 mm group. The differences between these two groups were not statistically significant. Improved outcomes were observed with ≥ 2 mm deep margins, but not for peripheral margins. High-risk tumors had better overall and disease-specific survivals with ≥ 2 mm margins. Subsites of the tongue, palate, mandible, and floor of the mouth had improved local control with ≥ 2 mm margins. CONCLUSION:Margins beyond 4 mm do not confer additional oncological benefit, while achieving ≥ 2 mm, especially in deep margins or high-risk tumors, is critical for optimal outcomes.

Medication-related osteonecrosis of the jaw (MRONJ) is a known adverse effect of antiresorptive and antiangiogenic therapies. However, reports of osteonecrosis linked to rituximab, a CD20 targeting monoclonal antibody, are exceedingly rare. We present a unique case of extensive maxillary MRONJ in a male 38 years of age with a background of multiple sclerosis receiving rituximab therapy. An initial presentation of acute sinusitis, progressed to bilateral maxillary bone destruction despite conservative management, multiple surgical interventions, and hyperbaric oxygen therapy. No other established MRONJ risk factors were identified including anti-resorptive use, antiangiogenic use, dento-alveolar surgery or dento-alveolar trauma. The extent of destruction, reaching the orbit and cranial base, is unprecedented in rituximab related cases. This report adds to the growing literature on rituximab associated MRONJ and emphasizes the need for increased awareness and understanding of this monoclonal antibody being a potential risk factor for MRONJ.

INTRODUCTION:Virtual reality (VR) is increasingly being explored in surgical education for its potential to create immersive training environments. However, many VR systems are expensive and require complex setups, limiting their accessibility. This survey study assesses the feasibility of cost-effective VR training on the education of oral maxillofacial surgical trainees and practitioners. Given the limited opportunities for hands-on practice in performing major surgical procedures, cost-effective VR training can provide an essential and accessible platform for developing surgical skills. MATERIALS AND METHODS:Cadaver surgery videos of complex maxillofacial procedures were created in 360° VR and 2D formats and published on YouTube. Trainees enrolled in a cadaver course were surveyed after viewing both formats. Fifteen trainees completed questionnaires comparing their learning experiences, with responses analyzed using Fisher's exact test. RESULTS:About 73.3% of participants found the VR video improved their understanding of the procedure, and over 75% reported enhanced spatial awareness. However, 86.6% experienced discomfort or motion sickness. In comparison, 66.6% felt the 2D video helped their understanding, and only 40% found it improved spatial awareness. No statistically significant difference was found between the VR and 2D formats for procedural understanding or spatial awareness. Notably, participants rated the VR video as more intuitive and user-friendly compared to the standard 2D video, with the difference achieving statistical significance. Overall, 66.6% preferred the VR format, while 33.3% favored 2D. CONCLUSION:This feasibility study highlights the utility of a cost-effective VR solution for enhancing maxillofacial surgery training, providing a practical option for preparing trainees for real-life scenarios.

BACKGROUND:Monitoring delivery of cancer care is critical to improve outcomes in increasingly resource-constrained settings. The aim of this study was to develop a priority set of multidisciplinary quality indicators (QIs) for benchmarking and monitoring the quality of care for head and neck cancer (HNC) in Australia. METHODS:Following a systematic literature review, a modified Delphi consensus process was undertaken with Australian health professionals and people with lived experience of HNC. Consensus was sought over three rounds. In Rounds 2 and 3, participants rated the importance of QIs on a scale of 1 (not at all important) to 7 (highly important). QIs reached consensus if they had a mean importance score ≥ 6 (out of 7) and ≥ 75% of participants rated them 6 or 7. RESULTS:The systematic review identified 317 unique QIs, and 81 were chosen for presentation in Rounds 2 of the Delphi. In Round 2, 66 health professionals and 12 people with lived experience of HNC reached consensus on 48 QIs, with three reworded and one new QI added. Fifty-two QIs were presented in Round 3; 42 health professionals and 10 people with lived experience participated, reaching consensus on 24 QIs. Most of the QIs fell under the treatment domain, with commencement of curative treatment and documentation of surgical margins attaining the highest consensus. CONCLUSION:We developed a priority set of 24 clinically relevant QIs for HNC, which will be tested in a clinical quality registry to benchmark optimal management of HNC and outcomes.

BACKGROUND:Subperiosteal implants were commonly used for dentally rehabilitating atrophic maxillae and mandibles in the 1940s-1980s, losing popularity following the introduction of endosseous root-formed osseointegrated implants. RESULTS:Historically, subperiosteal implants had regular complications of hardware exposure, implant mobility, and pain, resulting in the removal of the implant. The transmucosal posts appear to be the primary cause of failure due to bacterial colonization and propagation down the implant substructure. These implants are currently regaining interest due to their applications for dentally rehabilitating patients following an oncological ablation. CONCLUSION:For these implants to return to the dental and maxillofacial industry, contemporary techniques of bone grafting and implant materials should be explored. This review discusses the historical issues with subperiosteal implants and avenues for the improvement of long-term outcomes in the 21st century.

Oral cancer (OC) is the most common form of head and neck cancer. Despite the high incidence and unfavourable patient outcomes, currently, there are no biomarkers for the early detection of OC. This study aims to discover, develop, and validate a novel saliva-based microRNA signature for early diagnosis and prediction of OC risk in oral potentially malignant disorders (OPMD). The Cancer Genome Atlas (TCGA) miRNA sequencing data and small RNA sequencing data of saliva samples were used to discover differentially expressed miRNAs. Identified miRNAs were validated in saliva samples of OC ( n = 50), OPMD ( n = 52), and controls ( n = 60) using quantitative real-time PCR. Eight differentially expressed miRNAs (miR-7-5p, miR-10b-5p, miR-182-5p, miR-215-5p, miR-431-5p, miR-486-3p, miR-3614-5p, and miR-4707-3p) were identified in the discovery phase and were validated. The efficiency of our eight-miRNA signature to discriminate OC and controls was: area under curve (AUC): 0.954, sensitivity: 86%, specificity: 90%, positive predictive value (PPV): 87.8% and negative predictive value (NPV): 88.5% whereas between OC and OPMD was: AUC: 0.911, sensitivity: 90%, specificity: 82.7%, PPV: 74.2% and NPV: 89.6%. We have developed a risk probability score to predict the presence or risk of OC in OPMD patients. We established a salivary miRNA signature that can aid in diagnosing and predicting OC, revolutionising the management of patients with OPMD. Together, our results shed new light on the management of OC by salivary miRNAs to the clinical utility of using miRNAs derived from saliva samples.

Postoperative neck infection (PONI) is a known complication of neck dissection. In this study we explored the impact of dental status on the development of PONI, using orthopantomograms to assess edentulism, periodontal health, and caries status. Retrospective analysis was performed for all new oral cancer patients who had neck dissection between January 2008 and January 2020 in a tertiary head and neck centre. PONI risk factors assessed included patient characteristics, dental status, tumour, and surgical factors. Development of PONI was the primary outcome. Edentulous patients had lower risk of PONI (OR 0.06, p = 0.026) compared to those with 21 or more teeth. Periodontitis and dental caries were not statistically significant. Current smokers (OR 2.09, p = 0.044) and free flap reconstruction (OR 5.41, p < 0.001) were also significant predictors for development of PONI. This study highlights the presence of teeth as a potential source of infection post neck dissection and that orthopantomogram assessment may be inadequate to identify at risk patients. Future studies are required on direct clinical assessment of dentition to evaluate the impact of dental optimisation in prevention of PONI.

INTRODUCTION:The profile and outcomes of head and neck cancer throughout Australia has changed over the past decade. The aim of this study was to perform a population-based analysis of incidence, demographics, stage, treatments and outcomes of patients diagnosed with oropharyngeal squamous cell carcinoma (OPSCC), with a particular focus on HPV-associated disease. METHODS:This was a retrospective analysis of prospectively collected data within the Queensland Oncology Repository (QOR) and analysed by the Queensland Cancer Control Analysis Team. The cohort included patients diagnosed in Queensland between 1 January 2015 and 31 December 2019. Outcome measures included incidence of new OPSCC cases, age-standardised rates (ASR) (3-year average), demographics, p16 status, stage (8th Edition American Joint Commission on Cancer), treatments, and 2- and 5-year overall survival. RESULTS:There were 1527 newly diagnosed OPSCC, representing 96% (1527/1584) of all oropharyngeal cancers. It was the most common head and neck cancer diagnosed, with oral cavity cancer being the second most common (n = 1171). Seventy-seven percent were p16 positive (1170/1527), of which 87% (1019/1170) were male. The median age was 61 years and 49% (568/1170) presented with Stage I disease. The ASR was 6.3/100,000, representing a 144% incidence increase since 1982 (2.6/100,000). Radiotherapy was utilised in 91% of p16+ cases with 2- and 5- year overall survival of 89% and 79%, respectively. CONCLUSION:OPSCC is now the most common mucosal head and neck cancer diagnosed in Queensland, having surpassed oral cavity cancer. The majority are HPV-associated (p16+), presenting with early-stage disease with a favourable prognosis.

BACKGROUND:Head and neck squamous cell carcinoma (HNSCC) is linked to human papillomavirus (HPV) infection. HPV-positive and HPV-negative HNSCC exhibit distinct molecular and clinical characteristics. Although checkpoint inhibitors have shown efficiency in recurrent/metastatic HNSCC, response variability persists regardless of HPV status. This study aimed to explore the CD8+ T-cell landscape in HPV-negative HNSCC. METHODS:We performed simultaneous single-cell RNA and TCR sequencing of CD8+ tumor-infiltrating lymphocytes (TILs) from treatment-naïve HPV-negative HNSCC patients. Additionally, cells were stimulated ex vivo, which allowed for the tracking of clonal transcriptomic responses. RESULTS:Our analysis identified a subset of CD8+ TILs highly enriched for interferon-stimulated genes (ISG). TCR analysis revealed ISG cells are clonally related to a population of granzyme K (GZMK)-expressing cells. However, unlike GZMK cells, which exhibited rapid effector-like phenotypes following stimulation, ISG cells were transcriptionally inert. Additionally, ISG cells showed specific enrichment within tumor and were found across multiple tumor entities. CONCLUSIONS:ISG-enriched CD8+ TILs are a consistent feature of various tumor entities. These cells are poorly understood but possess characteristics that may impact antitumor immunity. Understanding the unique properties and functionality of ISG cells could offer innovative treatment approaches to improve patient outcomes in HPV-negative HNSCC and other cancer types.

BackgroundAmeloblastoma is a locally aggressive, benign tumor presenting in the maxilla and mandible prone to recurrence. Resection greatly limits recurrence, however, reconstruction becomes critical to preserve patients’ functionality and aesthetics.PurposeThe aim of this study was to describe surgical resection and reconstructive approaches in the treatment of ameloblastoma, and compare clinical outcomes to conservative methods of treatment.Study Design, Setting, SampleA retrospective case series was completed through analysis of patient records. The study population composed of patients treated for ameloblastoma at the Royal Brisbane Hospital (Queensland, Australia) in the Oral and Maxillofacial Surgery Unit from 1 January 2008 to 31 December 2020. Patients without histological confirmation of intraosseous ameloblastoma were excluded from the study sample.PredictorNot applicable.Main outcome variable(s): The primary outcome variable was time to recurrence. Secondary outcome variables included any surgical complications incurred.CovariatesThe covariate variables collected included age at diagnosis/treatment, gender, ethnicity, location of lesion and site(s) of involvement, tumor extent, alveolar expansion, histopathological growth pattern, soft tissue involvement.AnalysesDescriptive statistics were computed for each study variable.ResultsA total of 48 cases of histologically confirmed ameloblastoma were identified (41 mandibular, 7 maxillary) involving 50 excisional operations (44 resections, 6 enucleations). Of these cases, 44 were followed up >12 months, with a mean length of follow-up time of 65.6 months. No recurrence was detected for resected lesions. One enucleated lesion recurred at 25 months. 37 reconstructive procedures were undertaken, including 32 immediate free flaps. All reconstructive flaps and grafts survived, and no major complications were recorded.Conclusions and RelevanceResection of ameloblastoma limits recurrence and should be considered curative. Immediate microvascular free flap reconstruction of maxillary and mandibular defects from resection of ameloblastoma are safe and predictable.

Background: Despite introduction of extranodal extension (ENE) into the AJCC 8th edition of oral cancer staging, previous criticisms persist, such as limited discrimination between sub-stages and doubtful prognostic value of contralateral nodal disease. The purpose of this study was to compare our novel nodal staging system, based on the number of positive nodes and ENE, to the AJCC staging system in surgically treated patients. Methods: Retrospective analysis of 4710 patients with oral squamous cell carcinoma (OSCC) treated with surgery +/- adjuvant therapy in 8 institutions in Australia, North America and Asia. With overall survival (OS) and disease specific survival (DSS) as endpoint, the prognostic performance of AJCC 8th and 7th editions were compared using hazard consistency, hazard discrimination, likelihood difference and balance. Results: Our new nodal staging system (PN) a progressive and linear increase in hazard ratio (HR) from pN0 to pN3, with good separation of Kaplan Meier curves. Using the predetermined criteria for evaluation of a staging system, our proposed staging model outperformed AJCC 8th and 7th editions in prediction of OS and DSS. Conclusion: PN was the lymph node staging system that provided the most accurate prediction of OS and DSS for patients in our cohort of OSCC. Additionally, it can be easily adopted, addresses the shortcomings of the existing systems and should be considered for future editions of the TNM staging system.

•Due to late diagnosis, prognosis is poor oral squamous cell carcinoma (OSCC).•Salivary exosomes may be used as a biomarker to early diagnose OSCC.•High exosome yields were detected in whole mouth saliva sample fraction.•Three-protein panel was able to discriminate cancer-free controls from cancer cases.•Results suggests salivary exosomal protein can be used as diagnostic biomarkers.

Background: A poor evidence basis exists regarding the objective donor site morbidity associated with osseous free flap harvest. This study prospectively assessed the objective donor site morbidity associated with osseous free flap harvest for the fibula, scapula, and iliac crest (DCIA) donor sites. Methods: A single-site, prospective cohort clinical research study was conducted. Sixty-four patients were recruited between 2017 and 2021. Patients were assessed using a donor site specific assessment tool pre-operatively, and again >12 months post-operatively. Results: There was a significant reduction post-operatively in assessment tool scores compared to the pre-operative period for the fibula, scapula and DCIA. Females were more likely to report a greater reduction in Harris Hip Score post-operatively compared to males. Conclusions: The fibula, scapula, and DCIA donor sites are associated with reduced objective function post-operatively compared to patient's pre-operative baseline. The implications are least pronounced for the fibula.

Bone regeneration in the orofacial region is a significant health and economic burden. While surgical techniques for the treatment of bone deficiencies have been developed, several challenges still remain. This chapter describes the most common surgical treatments for vertical bone augmentation and critically analyses their drawbacks while elaborating on the emergence of additive manufacturing in this area. Pre-clinical research endeavours utilising 3D-printed scaffolds are then described and their perceived limitations are discussed. The final section of the chapter provides a description of current reconstruction techniques used in the case of severe bone atrophies and large-volume bone deficiencies prior to elaborating on the future of this field.

BackgroundPredictive nomograms are useful tools to guide clinicians in estimating disease course. Oral squamous cell carcinoma (OSCC) patients would benefit from an interactive prediction calculator that defines their levels of survival-risk specific to their tumors to guide the use of postoperative radiotherapy (PORT). MethodsPatients with OSCC surgically treated with curative intent at four Head and Neck Cancer Centres were recruited retrospectively for development and validation of nomograms. Predictor variables include PORT, age, T and N classification, surgical margins, perineural invasion, and lymphovascular invasion. Outcomes were disease-free, disease-specific, and overall survivals over 5 years. Results1296 patients with OSCC were in training cohort for nomogram analysis. Algorithms were developed to show relative benefit of PORT in survivals for higher-risk patients. External validation on 1212 patients found the nomogram to be robust with favorable discrimination and calibration. ConclusionThe proposed calculator can assist clinicians and patients in the decision-making process for PORT.

Patients undergoing radiotherapy for head and neck cancers are prone to a range of dental complications, including mucositis, trismus, xerostomia, radiation caries and osteoradionecrosis. Specific considerations include the preventive, restorative and rehabilitative management of such patients, and the prevention and treatment of complications. This article aims to highlight the current understanding and management of dental needs for patients who have had or will undergo radiotherapy.