Applications of artificial intelligence in restorative dentistry: a scoping review.

OBJECTIVE: Artificial intelligence (AI) applications in restorative dentistry have remarkably increased in the past 5 years. This review outlines the applications, promises, and limitations of AI in the most performed procedures in restorative dentistry. METHOD AND MATERIALS: An electronic search was performed in four databases: MEDLINE/PubMed, Embase, Web of Science, and Scopus. The search included articles published in English language without date restriction. Two independent reviewers assessed the eligibility of the studies and performed data extraction. Any discrepancy was resolved by the consensus of a third reviewer. RESULTS: A total of 33 studies were included in this review. For AI applications in restorative dentistry, the included studies were classified into three main groups: (1) diagnosis, detection, and prediction of the disease, (2) detection and prediction of the longevity of dental restorations, and (3) teeth detection and treatments. For each study, the AI model, type of dataset, sample size, and main results (accuracy, precision, sensitivity, and specificity) were reported. CONCLUSIONS: AI systems are promising as advantageous aids for diagnosis, prediction, and treatment in dentistry, with a high degree of accuracy. Despite the AI promises, several limitations are still unresolved and must be addressed to bridge the gap between technology and clinical applications.

Effect of different impression coping and scan body designs on the accuracy of conventional versus digital implant impressions: An in vitro study.

OBJECTIVES: This in vitro study compared the accuracy of conventional versus digital impression techniques for angulated and straight implants using two different impression coping and scan body designs. METHODS: Two implant systems were used: Straumann and Dentegris. Two implants were placed for each system, straight and angulated at 15 degrees mesiodistally. Conventional impressions were made using the splinted open-tray technique using narrow impression coping (NIC) and wide impression coping (WIC). The stone casts produced from the conventional impression were digitized with a lab scanner (3Shape D2000). Digital impressions were made using four intraoral scanners (IOS): 3Shape Trios 3, Medit i700, Cerec Omnicam, and Emerald Planmeca using short scanbodies (SSB) and long scanbodies (LSB). The scanning was repeated ten times to generate the Standard Tessellation Language (STL) files. The distance and angle deviations between impression copings and scanbodies were measured in reference to the master model. RESULTS: The trueness and precision of SSB and WIC were significantly better than LSB and NIC (p<0.001). The range trueness of the platform deviation was better with SSB (37.1 to 51.9) than LSB (89.6 to 127.9 µm) and for WIC than NIC in conventional impressions (58.2 and 75.1 µm, respectively). The trueness of the angle deviation of digital scans with SSB (0.11 to 0.25 degrees) was significantly better than scans with LSB (0.31 to 0.57 degrees) and for WIC than NIC (0.21 and 0.52 degrees, respectively). The precision of the platform deviation of digital scans with SSB (12.4 to 34.5 µm) was higher than other scans and conventional impressions (42.9 to 71.4 µm). The precision of the angle deviation of Medit i700 and Trios 3 with SSB (0.17 and 0.20 degrees, respectively) was higher than other scans with SSB and conventional impressions (0.54 to 1.63 degrees). CONCLUSIONS: Digital scans with SSB were more accurate than conventional splinted open-tray impressions. The type of impression coping and scanbody significantly affected the impression accuracy. CLINICAL SIGNIFICANCE: The use of a short scanbody can increase the accuracy of digital impressions, and wide impression coping can increase the accuracy of conventional impressions, resulting in improved clinical outcomes.

Characteristics of Suture Materials Used in Oral Surgery: Systematic Review.

BACKGROUND: The aim of this review was to evaluate the most used suture materials with regards to their inflammatory response, their bacterial adhesion, and their physical properties when used to close oral wounds. METHODS: Four databases (PubMed, Scopus, Dentistry & Oral Sciences, and OVID) were searched to retrieve relevant studies from January 1, 2000, to January 31, 2020. RESULTS: Out of the 269 articles, only 13 studies were selected as they were relevant and met the systematic review's protocol. These studies showed that almost all suture materials studies (catgut, polyglycolic acid [PGA] sutures, nylon, expanded polytetrafluoroethylene, and silk sutures) caused bacterial adherence and tissue reaction. In nylon and chromic catgut, the number of bacteria accumulated was lowest. Silk and nylon were found to be more impacted than catgut and PGA in terms of physical characteristics such as tensile strength. PGA, on the other hand, was said to be the most susceptible to knot unwinding. CONCLUSIONS: Following an oral surgical operation, all sutures revealed varied degrees of irritation and microbial accumulation. Nonresorbable monofilament synthetic sutures, however, exhibited less tissue response and less microbial accumulation.

Quality of life following photodynamic therapy for head and neck pathologies: An exploratory study.

INTRODUCTION: Healthcare related quality of life (QoL) is defined as the impact one's level of health and wellbeing has on a number of domains, including physical, mental, spiritual and social functions. Photodynamic therapy (PDT), a cancer treatment modality, is increasingly used to treat or palliate head and neck pathologies. Due to the complex nature of this area of the body, both the pathology and the treatment of it can severely affect the quality of life. Thus far, no questionnaire has been developed which focuses on quality-of-life post-PDT of head and neck pathologies. PATIENTS AND METHODS: We have developed the University College London Quality of Life Questionnaire for Patients undergoing PDT in the Head and Neck, using meta-tetra(hydroxyphenyl)chlorin (mTHPC) as the photosensitiser. This was modified from the University of Washington quality of life (UW-QOL) questionnaire. Thirty-eight patients who received mTHPC-PDT for various head and neck pathologies completed the questionnaire, with a mean follow-up of 56 days. RESULTS: All patients reported improved QoL following mTHPC-PDT. The main problem that was reported was post-PDT pain, which is a common side effect. Visual symptoms, breathing, speaking and swallowing problems improved significantly in the 4th week following treatment and significant improvement in activities of daily living, social life, mood and anxiety were reported in the subsequent weeks. CONCLUSIONS: mTHPC-PDT confers improvement in QoL score in selected head and neck cancer patients with figures comparable to other treatment modalities. This exploratory study demonstrated patterns of QoL outcome. Further work needs to be done for survey validation and inclusion of a larger cohort which will allow optimal sub-group analysis and help guide further interventions.

The consequences and outcomes associated with dental implants encroaching on adjacent teeth.

BACKGROUND: Dental implant placement carries a risk of iatrogenic damage to adjacent root surfaces. PURPOSE: To classify and understand different types of trauma to the tooth root body by dental implants. MATERIALS AND METHODS: This prospective case series included 43 implants placed between February 2017 and June 2020 that had primary stability and were in a position that accidentally invaded the adjacent teeth. The type and degree of the injury were evaluated clinically and radiographically. Tenderness, mobility, and sensitivity tests of the injured teeth were conducted at different visits. Implant failure was confirmed by the presence of implant mobility during the healing period. RESULTS: Overall, 43 patients had root injuries due to dental implant surgeries. Regarding the 43 injured roots, 32 developed transient tenderness to percussion, 16 developed variable degrees of resorption in the cementum, three lost pulp sensitivity and one had persistent tenderness to percussion. No injured teeth were lost. In three patients, implant periapical lesions were confirmed radiographically as radiolucency near the apex of the involved implants. Out of the 43 implants, 11 failed and were removed within 6 months, with an implant failure rate of (25%). CONCLUSIONS: Root damage after implant surgery varies depending on the type and severity of injury. Periodic clinical and radiographical examination is necessary to monitor root resorption and implant integration and to rule out pulp necrosis.

In vivo optical coherence tomography-guided photodynamic therapy for skin pre-cancer and cancer.

BACKGROUND: The primary aim of this prospective study is to demonstrate the technical feasibility of OCT to map real tumor margins and to monitor skin changes that occurred post- PDT. Moreover, to optimize PDT efficacy based on the relationship between measured OCT features and treatment outcome. MATERIAL AND METHODS: A series of 12 patients with overall 18 facial skin lesions were investigated by OCT before surface illumination by PDT to determine tumor free margins. Monitoring of the healing process was undertaken at 3, 6 and 12 months post-PDT. Parameters measured by the in vivo OCT during healing phase were the organization of skin layer and the degree skin fibroses for the active center and peripheral transit zone of the treated lesion. Clinical and aesthetics assessment was carried out at 12-month post-PDT. RESULTS: Distinct microstructural differences between normal skin, pre-cancer, cancer, and the transition zone between the two tissues were observed on OCT images. In the subsequent healing phase, OCT demonstrate marked delineation and organization of skin layer at late stage of healing. Early features showing bizarre non-homogenous disorganized layering (scab) but afterwards, OCT was able to differentiate between different histological layers. One lesion demonstrated clinical healing by fibrosis (scar) without sign of recurrence. Another lesion demonstrated skin erythema. Only one lesion did not response to treatment despite margins clearance. The CR rate was 95% at the end of the study. The cosmetic effect was "excellent" in 89% of the patients. CONCLUSIONS: This feasibility study lays the groundwork for using OCT as a real-time, noninvasive monitoring device for PDT in patients with skin cancer.

Squamous cell carcinoma of the ear treated by photochemical internalization.

A 77-year-old Caucasian male was diagnosed with squamous cell cancer of the right ear. The patient elected to take part in the first-in-man phase I TPCS2a based bleomycin photochemical internalization (PCI). On Day 0, The patient received the photosensitiser [Amphinex (TPCS2a)], by slow intravenous injection. Four days later, surface illumination based (PCI) was implemented 3 h after the slow infusion of Bleomycin. Four weeks following the infusion of the photosensitiser, the cancerous area turned into black rigid mass with clear demarcation from the macroscopically normal skin. The size of the treated area has been substantially reduced. Histopathologic assessment of the excised necrotic mass revealed no viable tumour and the excised margins (PCI-treated margins) were tumour-free. This case was a clear indication that PCI is a clinically relevant technique that has potential in the treatment of such cancers to avoid radical intervention.

In vivo optical coherence tomography in assessment of suspicious facial lesions: A prospective study.

BACKGROUND: Skin cancer continues to be the most common cancer in the Caucasian population. Over the past two decades, researchers around the world started assessing the possibility of diagnosing tissue pathologies by using optical systems. In this study, we aimed to use in vivo optical coherence tomography (OCT) technology to describe the morphologic features of normal and pathologic skin conditions. MATERIALS AND METHODS: In this study, 72 patients with suspected skin pre-cancer/cancer were recruited. The lesions were subjected to in vivo OCT scanning using compact size probe. The main scanned areas were the centre of the lesion, periphery of the lesion and control reading at least 2cm from the lesion periphery but within the same dermatomal distribution. Following assessment, each lesion was surgically excised. All acquired OCT images were correlated with the corresponding histopathology images to ensure an accurate diagnosis and appropriate co-localisation of abnormal lesion on both OCT image and pathology slide. This was achieved in every resected lesion. RESULTS: Histopathological analysis revealed that of the 96 macroscopically suspicious scanned lesions 26 were actinic keratosis (AK), 51 were basal cell carcinoma (BCC) and 19 were cutaneous squamous cell carcinoma (SCC). Different layers of healthy skin can be distinguished with clear demarcation between the epidermis and papillary dermis. An increase in epidermal thickness was observed in OCT images in AK that appeared relatively hyperintense. Cutaneous SCC was characterized by hypoechoic signal free spaces within the dermis and damaged of dermal-epidermal junction. BCCs were visualized as hypoechoic structures but showed a mixed echogenicity. Solid nodular BCC appeared as single or multiple areas with no clear arrangement surrounding low-reflectivity lobular structures surrounded. Cystic structures were identifiable by signal-free areas adjacent to healthy skin. Sensitivity and specificity for in vivo OCT in diagnosing these lesions were impressive, based on this small sample size. CONCLUSIONS: OCT have shown that there are qualitative differences in OCT image features of skin with varying degrees of pathology, and between normal and pathological skin. This study indicates that in vivo OCT shows a good promise as a useful optical diagnostic technique in diagnosing skin pathologies.

Prognostic significance of E-Cadherin, ß-Catenin and cyclin D1 in oral squamous cell carcinoma: a tissue microarray study.

OBJECTIVE: To study the prognostic significance of E-cadherin, ß-catenin, and cyclin D1 expression in oral squamous cell carcinoma. SUBJECTS AND METHODS: The study included 65 subjects with histologically confirmed squamous cell carcinoma. TMA blocks were prepared for immunohistochemical quantification of the expression of the three markers using IHC profiler and Immune ratio plugin of Image J. RESULTS: E-cadherin expression was significantly correlated with histological grades and the metastasis status (p<0.05), whereas ß-catenin expression was significantly correlated with smoking and tumor recurrence (P<0.05). Cyclin D1 expression was significantly correlated with depth of invasion and tumor recurrence. (p<0.05). Advanced tumor stage and depth of tumor invasion increases the risk of recurrence or death by 2.5 times (OR= 2.53 and 0.84 respectively). CONCLUSION: High expression of ß-Catenin and Cyclin D1 are significantly correlated with tumor recurrence and old age. Depth of invasion, low histological grade and old age were a significant predictor for the risk of having tumor recurrence and cancer related death.

Thermography as a non-ionizing quantitative tool for diagnosing periapical inflammatory lesions.

BACKGROUND: Thermography is a contemporary imaging modality based on acquiring and analyzing thermal data using non-contact devices. The aim of the present study was to assess the validity of thermography, compared with that of the reference-standard, for the diagnosis of periapical inflammatory lesions and to evaluate the temperature ranges for acute pulpitis with apical periodontitis (AAP), acute periapical abscess (AA) and chronic periapical abscess (CA). METHODS: AAP, AA and CA were diagnosed based on clinical and radiographic criteria. Thermographic data were acquired using the FLIR E-5 Infrared Camera. Extraoral thermal images were taken from the front and right and left sides of patients whose mouths were closed, and one intraoral thermal image was taken from the palatal perspective. Agreement in the diagnoses based on the combination of clinical and radiographic assessments and the thermographic evaluation was calculated. The temperature ranges of the three diagnostic subgroups were also measured. RESULTS: A total of 80 patients were enrolled in this study. The mean intraoral thermal image temperature for AA was 37.26 ± 0.36, that for CA was 35.03 ± 0.63 and that for AAP was 36.07 ± 0.45. The differences between the mean intraoral thermal temperatures of the three diagnostic groups were statistically significant (P < 0.001). The result of the Kappa coefficient of agreement between the combination of clinical and radiographic assessments and the thermographic evaluation was significant (P < 0.001). CONCLUSIONS: Thermography is an effective, quantitative and nonionizing approach that can be used for the diagnosis of periapical inflammatory lesions. The results of the present study indicated that the highest thermal image temperatures were recorded for AA. Thermography might be able to detect inflammatory reactions during the preclinical stage, leading to early diagnosis.

The role of differentially expressed salivary microRNA in oral squamous cell carcinoma. A systematic review.

OBJECTIVE: This study aims to systematically review the role of differentially expressed microRNA (miRNA) in saliva as potential biomarkers in oral cancer patients. DESIGN: PubMed, Scopus and EBSCO online data bases were used as well as manual searching to extract studies from January 2008 up to October 2020. RESULTS: A total of 14 studies that met the eligibility criteria were included. All selected studies were of case-control type. A total of 25 differentially expressed miRNAs were identified. Thirteen of these miRNAs (Let-7a, miR 27, miR 34, miR 92, miR 124, miR 125a, miR 136, miR139 miR 145, miR 146a, miR 200a, miR 205 and miR 375) were downregulated and other twelve (miR 9, miR 21, miR 31, miR 122, miR 134, miR 184, miR 191, miR 196a, miR 196b, miR 412, miR 512 and miR 8392) were upregulated. Four miRNAs were evaluated in more than one study (miR21, miR31, miR125 and miR 200). CONCLUSION: According to these results, salivary miRNA can aid in diagnosis and prognosis of oral squamous cell carcinoma (OSCC). However, controlled clinical trials with a large sample size are required to validate the differentially expressed miRNAs of the present review.

Evaluation of different surgical approaches to remove dental implants from the maxillary sinus.

Dental implant surgery on atrophied maxilla has many risks; in some patients, simultaneous sinus lifting with implant placement must be performed to increase the chances of successful implantation; this procedure can cause implant migration. Eleven patients were diagnosed with implant migration into the maxillary sinus in four anatomical areas: the sinus floor above the alveolar bone, near the junction of the sinus and nasal floor, near the floor of the orbit, and the most posterior aspect of the sinus. Surgical removal was performed through four different direct non-endoscopic transoral approaches depending on the location of the displaced implant. Surgical challenges, surgery duration and postoperative complications were reported. The least challenging surgical intervention was noted when removing the displaced implants from the floor of the sinus through the crestal approach. More challenges were experienced during the surgical removal of anteriorly displaced implants near the roof of the orbital floor due to surgical access and the proximity of vital anatomical structures. Bleeding from the pterygoid venous plexus was profound with the posterior lateral approach. The choice of an appropriate surgical approach to retrieve displaced dental implants from the maxillary sinus depends on the location of the implant and the surrounding vital anatomical structures.

Post COVID-19 lockdown: measures and practices for dental institutes.

Resuming regular clinical activities at dental premises after the COVID-19 lockdown period or post COVID-19 is likely to be a challenge for all dental institutes. When returning to the dental practice or training, staff and students alike should abide by the new rules and regulations. In the process of controlling viral spread, clinical dental facilities face a higher risk of disease transmission among patients as well as clinical and non-clinical staff. Aerosols formation and diffusion into the surrounding air can be a real concern of viral transmission, if no protective measures are established. We aim in this review to present the currently implemented measures and propose changes in clinical dental facilities to minimize the risk of transmission. Dental professionals should be prepared to treat every patient as a suspected COVID-19 carrier and be ready to receive and manage an overwhelming number of patients. We suggest that dental practices establish a sensible workforce shift schedule, improve ventilation levels, reduce dental aerosol generating procedures, and develop a comprehensive guidance to Healthcare Workers to reduce the risk of COVID-19 transmission.

Photochemical Internalization for Intracellular Drug Delivery. From Basic Mechanisms to Clinical Research.

Photochemical internalisation (PCI) is a unique intervention which involves the release of endocytosed macromolecules into the cytoplasmic matrix. PCI is based on the use of photosensitizers placed in endocytic vesicles that, following light activation, lead to rupture of the endocytic vesicles and the release of the macromolecules into the cytoplasmic matrix. This technology has been shown to improve the biological activity of a number of macromolecules that do not readily penetrate the plasma membrane, including type I ribosome-inactivating proteins (RIPs), gene-encoding plasmids, adenovirus and oligonucleotides and certain chemotherapeutics, such as bleomycin. This new intervention has also been found appealing for intracellular delivery of drugs incorporated into nanocarriers and for cancer vaccination. PCI is currently being evaluated in clinical trials. Data from the first-in-human phase I clinical trial as well as an update on the development of the PCI technology towards clinical practice is presented here.

Apparent Complete Response of a Treatment Refractory and Recurrent Squamous Cell Carcinoma Lesion to Photochemical Internalization: A Clinical Case Study.

Photochemical internalization (PCI) depends on the delivery of sublethal photodynamic reaction to facilitate the work of a chemotherapeutic agent. We discuss our experience in managing a patient with extensive squamous cell carcinoma of the right face and scalp under the TPCS2a -based bleomycin PCI treatment protocol. In this case, an 84-year-old Caucasian received 0.25 mg kg-1 of TPCS2a (Amphinex® , PCI Biotech AS, Oslo, Norway). Surface illumination photochemical internalization was carried out after 4 days, which was preceded by the chemotherapeutic agent infusion (Bleomycin). After one week from the illumination time, tissue necrosis was evident and tumor shrinkage was most noticeable at day 14 postillumination. Follow-up at 6 weeks continued to show tissue healing and regeneration with no clinical evidence of recurrence. Multiple surgical biopsies were taken at 1 and 3 months postillumination and found to be tumor free. PCI's depth of effect has been very significant with negligible damage to the collateral tissues. This technology has a role in interventional oncology especially when managing challenging cases.

Structural validation of facial skin using optical coherence tomography: A descriptive study.

BACKGROUND: In this immediate ex vivo study, we aimed to identify the structures of normal and pathological facial skin using optical coherence tomography (OCT) and compared them to the gold standard histopathology. MATERIAL AND METHODS: A total of 53 patients, with 57 suspicious facial lesions, participated in this study. A set of variables have been highlighted by the pathologist to represent the minimum unique features that could be used to diagnose a skin pathology have been included in a checklist. One pathologist used this checklist while examining the histopathology slides and one clinician while examining the OCT images. The data from both checklists have been reviewed and compared. RESULTS: Optical coherence tomography's overall accuracy in diagnosing AK was 83%. Best accuracy was achieved in diagnosing BCC and was 97%, while it was 85% for cutaneous SCC. OCT failed to diagnose LM with an accuracy of 33.3% based on the two parameters of the pathology checklist, while it was 81% for malignant melanoma. CONCLUSION: This study proved the success of OCT in identifying structural changes in normal and pathological facial skin. Further studies to prove its usefulness in vivo are recommended.

Optical coherence tomography in the assessment of cutaneous cancer margins of the face: An immediate ex vivo study.

BACKGROUND: The assessment of cutaneous cancer margins intra-operatively or in the immediate postoperative phase can guide the operator into achieving clear margins. Achieving clear (tumour-free) margins following surgery is an essential factor that can reduce morbidity and disfigurement. The aim of present study was to determine the accuracy of optical coherence tomography in assessing cutaneous cancer margins of the face. MATERIALS AND METHODS: The excised tissue specimens that were examined, in this study, were acquired from 70 patients with 70 facial cancer lesions, with no nodal disease. Forty lesions were basal cell carcinomas (150 margins; 27 tumour positive) and the remaining thirty were cutaneous squamous cell carcinomas (112 margins; 22 tumour positive). These 70 resected lesions were subjected to optical coherence tomography (OCT) in the immediate ex vivo phase to assess each specimen's four margins status (anterior, posterior, medial and lateral). Two reviewers, blinded to the diagnosis, carried out the assessment of the acquired OCT images and measured the mean thickness. Intra- and inter-reviewer agreement was also calculated. RESULTS: On OCT, tumour-involved margins displayed sudden change in thickness associated with architectural changes. BCC-involved margins showed homogenous oval nests with dark rim and dark cysts or an empty space below dermo-epidermal junction depending on the sub-type. In the case of cutaneous SCC-involved margins, the DEJ had lost its integrity with/out the presence of small bright clusters in the papillary dermis and damage to the superficial epidermal layers. The mean thickness of the whole epidermal layer of the tumour-free margin was 128 µm, while for the BCC-involved margin 640 µm, and for the cutaneous SCC-involved margin 810 µm. The sensitivity of using OCT in examining BCC-involved margins was 88.9-92.6 % and the specificity was 96.8-98.4 %. For cutaneous SCC-involved margins, the sensitivity was 81.8-91.0 % and the specificity 85.6-91.1 %. There was "strong" inter-reviewer agreement on the BCC-involved margins, while the agreement was "moderate" for the cutaneous SCC-involved margins. CONCLUSION: OCT provides good accuracy in identifying cutaneous cancer margins. This can potentially be used to guide and monitor resection in real-time. Tumour thickness could be measured due to the thin skin of the face, but may be more difficult to measure accurately in thick tumours and/or thick skin areas.

Periorbital skin cancers subjected to mTHPC-photodynamic therapy: A prospective study.

INTRODUCTION: Photodynamic therapy (PDT) is a relatively new method of treating skin cancers. This prospective study highlights the use of PDT in the management of basal cell carcinomas (BCCs) and T1N0 cutaneous squamous cell carcinomas (SCCs) involving the periorbital area. MATERIALS AND METHODS: Surface illumination PDT was offered under local anaesthesia. mTHPC was administered intravenously. A single-channel 652 nm diode laser was used for illumination, and light was delivered at 20 J/cm2 per site. Lesion response evaluation was carried out according to response evaluation criteria in solid tumours (RECIST). RESULTS: After the first round of treatment, all cutaneous T1N0 SCC patients had complete response (CR) and continued to be in remission until last clinic review. For BCC patients, 12/14 patients had CR. The two remaining patients underwent a second round of treatment and also achieved a CR. All BCC patients were in remission at the last clinic review. Using visual analogue scale (VAS), 15 patients reported that this treatment gave them "excellent" cosmetic outcome (VAS 9-10). CONCLUSION: Photodynamic therapy achieved high efficacy in the treatment of periorbital BCCs and cutaneous SCCs with greatly reduced morbidity and disfigurement.

Epithelial tissue thickness improves optical coherence tomography's ability in detecting oral cancer.

BACKGROUND: OCT is a non-invasive imaging technique that enables the measurement of epithelial thickness and architectural changes, which can help in the diagnosis of pre-cancerous and cancerous lesions. The purpose of the study was to assess whether epithelial tissue thickness improves optical coherence tomography's ability in detecting oral cancer. PATIENTS AND METHODS: Surgically resected oral margins from 60 patients diagnosed with oral squamous cell carcinoma were subjected to OCT. Three OCT measurements (immediate, 1 h and 24 h post-resection) were conducted per resected tissue specimen to look at the effect of saline and formalin on the specimen and its effect on the reproducibility of the OCT. OCT was, then, used to measure the epithelial tissue thickness in cancer-free and cancer-involved margins in eight oral anatomical locations. This data was, then, combined with architectural changes data to calculate the sensitivity and specificity. RESULTS: An overall of 189 cancer-free margins and 51 cancer-involved margins had their epithelial thickness measured using OCT and compared to histopathology. With regards to the validity of the OCT and histopathological measurements, epithelial thickness showed good correlation between different readings at all oral sites. With regards to the reproducibility of the OCT measurements, the mean epithelial thickness for all measurements at first (immediate) and second (1 h post-resection - saline preserved) measurements was not significantly different. Underestimation of the epithelial depth in cancer-free margins was 20 µm, while in the cancer-involved margins was 10 µm. Combining data from architectural changes and epithelial thickness, a sensitivity of 92% and a specificity of 94% was achieved. CONCLUSION: Oral epithelium measurements using OCT were valid compared to those made with gold standard pathology. Measurements made using OCT was also reproducible with minor underestimation. Epithelial thickness, combined with architectural changes, led to high accuracy in differentiating between cancer-free and cancer-involved margins.