Oral Lesions in a Teaching Clinic: A Retrospective Study and Systematic Review

Abstract

Background/Objectives: Oral lesions can present with a wide range of clinical appearances, often making diagnosis challenging, particularly for dental students. This study aimed to identify the most common oral lesions treated at a teaching dental clinic and to compare these findings with data from a systematic review of similar clinical settings. The goal was to inform and calibrate a clinical classification system for oral pathology used in teaching environments. Methods: A retrospective analysis was conducted using electronic medical records from a university dental clinic over the past 10 years. Oral and maxillofacial pathology cases were categorized based on clinical and histopathological diagnoses. A systematic review was also performed to provide external context, with searches conducted across four electronic databases. Two independent reviewers carried out the study selection, data extraction, and quality assessment. The review adhered to the PRISMA guidelines. Results: A total of 524 patients were identified with oral lesions. The most frequently encountered clinical diagnostic category was developmental defects, while the most common histopathological diagnosis from biopsied cases was epithelial atypia. The systematic review yielded 1215 records, of which 69 were retrieved for full-text assessment, and 28 studies met the inclusion criteria. Conclusions: The findings highlight the predominance of specific oral and maxillofacial pathoses in teaching clinic settings, underscoring the importance of targeted educational strategies to improve diagnostic confidence among students. There is also a need for more consistent diagnostic grouping in oral pathology to enable better comparison across studies and support clinical and pre-clinical teaching. By integrating these insights, we propose a referenced classification framework that may improve standardization in the clinical teaching of oral lesions and enhance diagnostic calibration and teaching effectiveness in dental education.

1. Introduction

Oral diseases have a wide variety of appearances and therefore may represent a significant diagnostic challenge for clinicians. Accurate identification of specific pathologies is crucial for appropriate treatment planning and can significantly impact patients’ prognosis [1]. Several studies have evaluated the prevalence of the most common oral lesions across different countries. While two studies in the United States surveyed numerous patients, they are dated, having been conducted several decades ago [2,3]. Similar studies have also been conducted in Britain, India, and New Zealand [4,5,6]; however, various factors such as focusing solely on pediatric patients or specific types of lesions, e.g., reactive, limit their applicability.

Dental education in oral pathology faces challenges due to the lack of clinical classification of oral lesions. The dental curriculum should ideally be based on the prevalence and proper subtyping of each oral lesion. However, the extensive number of pathological conditions requires a significant amount of memorization from students. Moreover, the way these entities are categorized influences clinical differential diagnosis, which is crucial for success in oral medicine and pathology, both in educational and clinical settings.

Furthermore, the COVID-19 pandemic has worsened the existing shortcomings in dental education in oral pathology. Clinical experience plays a vital role in transitioning from student to competent practitioner, but the decreased number of in-person patient visits to dental schools due to the pandemic is likely to have long-lasting effects [7]. Previous research indicates that dental students themselves are worried about the potential inadequacy of their clinical education due to restrictions on patient care during their learning [8].

The aim of this study was to gain an understanding of the types and frequency of specific oral pathology diagnoses at a specific university-based teaching dental clinic and at clinics in other locales in order to compare the results for proper calibration of the oral pathology clinical categorization system that is taught to dental students.

2. Materials and Methods

2.1. Systematic Review

This systematic review (registered at the International Prospective Register of Systematic Reviews—PROSPERO) CRD42024460041 was conducted in accordance with the guidelines of Preferred Reporting Items for Systemic Reviews and Meta-Analyses Statement Criteria (PRISMA) [9]. Our research question was: “What are the most common oral lesions encountered in a teaching dental clinic, and how do these compare with findings from similar clinical settings worldwide?” Eligibility Criteria: We included fully accessible papers in English, published in peer-reviewed journals, and observational studies conducted after 1950. Excluded were duplicate publications, articles that did not report prevalence or frequency data on oral lesions in clinical or educational settings, non-English articles, reviews and other systematic reviews, studies centered on pediatric populations, studies exclusively examining a single type of lesion, and studies falling below a specified quality threshold. Search Strategy and Quality Assessment: Four databases were used to search the literature: PubMed, Google Scholar, Europe PMC, and Scopus. For Google Scholar, the key words utilized were as follows: “Oral lesion” AND biopsy AND pathology AND Review AND retrospective AND Frequency -pediatric -children” were used. For Europe PMC, “Prevalence AND distribution AND “oral lesions” AND Retrospective NOT pediatric” were the search terms. SCOPUS was searched with “Oral lesion” AND biopsies AND “Oral Pathology” NOT pediatric.” Finally, Pubmed was searched using the terms “Retrospective AND (Prevalence OR Frequency) AND biopsy AND Oral AND Maxillofacial AND Pathology NOT Children NOT pediatric”.

The search strategies were developed based on our PICOS criteria (Population, Intervention, Comparison, Outcome, and Study design), and the keywords were selected according to Medical Subject Heading (MeSH) terms. The relevant studies that met the inclusion and exclusion criteria were read fully and evaluated using the JBI Critical Appraisal Checklist for studies reporting prevalence data [4]. Studies failing to pass this checklist were excluded. Figure 1 outlines our systematic review search strategy. Data Extraction: Data extracted from the chosen literature included study title, authors, year of publication, country in which the study was conducted, most common diagnostic categories, most common specific lesions, source of analyzed data, whether clinical or histopathological diagnoses were used, sample size, and age range of subjects. Diagnostic categories and specific lesions were extracted from each included study based on the terminology used by the original authors. These were then grouped into broader analytical categories to allow for cross-study comparison. When necessary, synonymous terms were consolidated under a single category (e.g., ‘fibroepithelial polyp’ and ‘irritation fibroma’). This categorization aimed to reduce heterogeneity and facilitate meaningful comparison between the empirical data and the literature. Data was recorded on the Covidence production platform.

2.2. Retrospective Study

An analysis of all oral pathology reports and specimens submitted from our dental clinic between the past 10 years was performed. The frequency of the most prevalent lesions was calculated and analyzed, and a systematic review of the literature was conducted to contextualize the results.

Analysis of oral pathology data: Ethical approval for this study was granted by the responsible Biomedical Research Ethics Board of our university. The University Dental Clinic maintains an electronic record of all patient data in AxiUm, an academic dental software program (version 7.07.02.80). Three strategies were used to search the AxiUm database to obtain the patient files of patients presenting with oral pathologic lesions: (1) oral pathology subjective, objective, assessment, and plan (SOAP) forms; (2) diagnosis codes corresponding to lesions; and (3) oral pathology rosters (Figure 2).

The resulting patient files were then reviewed for the presence of oral mucosal and maxillofacial lesions, and data—including patient age, medical history, sex, lesion anatomic site and description, clinical diagnosis, and differential diagnosis provided—were collected into a spreadsheet.

Patients who underwent an oral biopsy procedure had additional clinical information available in their patient files specific to their given oral lesions. Consequently, we established two distinct pathways: one for lesions diagnosed solely through clinical examination and the other for lesions that were biopsied. The myriad of lesions observed were classified into categories adapted from Neville et al.’s textbook Oral and Maxillofacial Pathology [10] as follows: bone pathology, dermatologic diseases, developmental cysts, developmental defects, epithelial pathology, facial pain and neuromuscular conditions, immunologic disease, infectious disease, oral manifestations of systemic diseases, periodontal disease, physical and chemical injuries, pulp and periapical disease, salivary gland pathology, and soft tissue tumors. Exclusion criteria included cases handled solely by Oral Medicine, such as temporomandibular dysfunction, as well as odontogenic cysts and inflammatory pulpal disease managed under the supervision of clinical group practice leaders and endodontics specialists. The relative frequencies of the classes of lesions were quantified manually, and graphs for both the clinical and biopsied streams were created to illustrate the data.

3. Results

3.1. Systematic Review

Our systematic review search resulted in 28 studies from 18 different countries (

Table 1. Data extraction from the systematic review.

Author	Title	Country	Year	Site	Methods	Population	Inclusion Criteria	Limitation	Number	Age	Lesion Categories	Lesion Frequency
Yakin 2016 [11]	Oral and maxillofacial pathology submitted to Rizgary Teaching Hospital: a 6-year retrospective study	Iraq	2016	Department of Histopathology, Rizgary Teaching Hospital	Histopathologic evaluation	Patients who had a biopsy taken between 2008 and 2013	Site of lesion	N/A	616	0–90	1. Mucosal and skin pathology (33.9%) 2. Benign tumors (24.2%) 3. Malignant tumors (16.2%) 4. Miscellaneous (11.0%) 5. Cysts (8.0%) 6. Salivary gland pathology (6.7%)	1. Pyogenic granuloma (10.5%) 2. SCC (10.2%) 3. Fibroepithelial polyp (9.1%) 4. Pleomorphic adenoma (6.8%) 5. Haemangioma (3.9%) 6. Reactive lymphoid hyperplasia (3.7%) 7. Mucocele (3.4%) 8. Sialadenitis (3.2%) 9. Giant cell granuloma (3.1%) 10. Ameloblastoma (2.9%)
Al-Mobeeriek 2009 [12]	Prevalence of oral lesions among Saudi dental patients	Saudi Arabia	2009	Dental outpatients	Both	Adult patients admitted to the Oral Diagnostic Clinic at King Saud University, College of Dentistry	Older than 15 years	N/A	383	15–73	N/A	1. Fordyce granules (25.6%) 2. Leukoedema (22.5%) 3. Traumatic ulcer (12.5%) 4. Fissured tongue (9.4%) 5. Torus palatinus (8.9%) 6. Frictional hyperkeratosis (6.0%) 7. Tongue tie (3.9%) 8. Hairy tongue (3.7%) 9. Melanosis (3.7%) 10. Nicotinic stomatitis (3.4%)
Alhindi 2019 [13]	A retrospective study of oral and maxillofacial pathology lesions diagnosed at the Faculty of Dentistry, King Abdulaziz University	Saudi Arabia	2019	Oral Pathology Laboratory	Histopathologic evaluation	Patients at King Abdulaziz University oral pathology laboratory	Specimens between 1996 and 2016	N/A	N/A	0–85	1. Reactive/adaptive lesions (20.1%) 2. Cystic lesions (17.6%) 3. Inflammatory lesions (12.5%) 4. Epithelial lesions (9.4%) 5. Benign mesenchymal (8.7%) 6. Miscellaneous lesions (7.6%) 7. Malignancy (5.7%) 8. Immune-mediated diseases (4.9%) 9. Salivary gland (4.9%) 10. Odontogenic tumor (3.7%)	1. Radicular and residual cysts (11.0%) 2. Periapical granuloma (9.4%) 3. Fibroma (6.2%) 4. Hyperkeratosis and acanthosis (5.4%) 5. Fibroepithelial polyp (5.3%) 6. Pyogenic granuloma (5.2%) 7. Nonspecific inflammation (4.8%) 8. Lichen planus (4.4%) 9. SCC (3.8%) 10. Dentigerous cyst (3.1%)
Ulaganathan 2020 [14]	Retrospective analysis of oral and maxillofacial biopsies: An institutional study	India	2020	CSI Dental College records	Histopathologic evaluation	Patients who received biopsy between 2007 and 2018	N/A	Lack of information, irrelevant diagnosis	904	5–85	N/A	1. Traumatic fibroma (15.9%) 2. Periapical cyst (12.9%) 3. Pyogenic granuloma (9.5%) 4. Dysplasia (9.3%) 5. SCC (7.3%) 6. Ameloblastoma (5.3%) 7. Osteomyelitis (4.0%) 8. Lichen planus (3.5%) 9. Mucocele (3.5%) 10. Periapical granuloma (3.5%)
Nishat 2021 [15]	A Study on Prevalence of Oral Mucosal Lesions in the Geriatric Population of Eastern India	India	2021	The Oral Pathology Department of the Patna Government Hospital	Clinical examination	Patients aged 60 years and older attending the Oral Pathology Department	Clinical diagnostic features	Developmental conditions	N/A	60–95	1. Pre-malignant lesions (55.6%) 2. Reactive lesions (22.7%) 3. Tongue lesions (19.5%) 4. Denture-related lesions (16.0%) 5. Immune-mediated lesions (14.3%) 6. Infectious lesions (14.1%) 7. Malignant lesions (3.3%) 8. Pigmented lesions (2.5%)	1. Leukoplakia (19.0%) 2. Atrophic tongue (16.7%) 3. Oral submucous fibrosis (14.8%) 4. Lichen planus (14.3%) 5. Smoker’s palate (13.2%) 6. Traumatic ulcer (11.5%) 7. Angular cheilitis (9.6%) 8. Tobacco pouch keratosis (8.7%) 9. Candidiasis (7.9%) 10. Herpetic lesions (6.2%)
Das 2022 [16]	A retrospective study of oral and maxillofacial pathology lesions diagnosed at The Calcutta National Medical College & Hospital, Kolkata	India	2022	Department of Pathology, Calcutta National Medical College	Histopathologic evaluation	Patients who had visited the Oral Pathology department between 2017 and 2020	N/A	N/A	418	20–77	1. Reactive lesions (20.6%) 2. Cystic lesions (17.8%) 3. Inflammatory lesions (12.4%) 4. Epithelial lesions (9.5%) 5. Benign mesenchymal tumors (8.2%) 6. Malignant tumors (6.3%) 7. Immune-mediated diseases (5.1%) 8. Salivary gland pathology (4.9%) 9. Odontogenic tumors (3.6%) 10. Bone pathology (2.5%)	1. Radicular and residual cysts (9.3%) 2. Periapical granuloma (9.3%) 3. Fibroepithelial polyp (6.5%) 4. Pyogenic granuloma (5.7%) 5. Hyperkeratosis and acanthosis (5.5%) 6. Fibroma (5.0%) 7. Inflammation (4.8%) 8. Lichen planus (4.6%) 9. SCC (3.8%) 10. Dentigerous cyst (3.4%)
ElToum 2018 [17]	Prevalence and Distribution of Oral Mucosal Lesions by Sex and Age Categories: A Retrospective Study of Patients Attending Lebanese School of Dentistry	Lebanon	2018	Medical records of the Lebanese School of Dentistry	Clinical examination	Patients attending the Lebanese University for dental treatments	Medical records between October 2014 and May 2015	Lack of written information, not evaluated by a doctor of the pathology department	178	10–92	N/A	1. Coated/hairy tongue (17.4%) 2. Melanotic macule (11.2%) 3. Gingivitis (9.6%) 4. Linea alba(6.2%) 5. Tongue depapillation (5.1%) 6. Leukoplakia (5.1%) 7. Traumatic fibroma (4.5%) 8. Frictional keratosis (3.9%) 9. Fissured tongue (3.9%) 10. Fordyce granules (3.9%)
Collins 2021 [18]	Prevalence of oral mucosal lesions in an adult population from eight communities in Santo Domingo, Dominican Republic	Dominican Republic	2021	Volunteers from Santo Domingo communities	Clinical examination	Adults from eight Dominican Republic communities	General good health, 18 years or older	N/A	248	18–86	N/A	1. Melanin pigmentation (25.0%) 2. Palatal/mandibular tori (20.2%) 3. Fordyce granules (7.9%) 4. Exostosis (5.6%) 5. Denture stomatitis (2.8%) 6. Nicotine stomatitis (2.5%) 7. Periodontal disease (2.3%) 8. Pericoronitis (2.2%) 9. Smoker melanosis (2.2%) 10. Leukoedema (2.2%)
Monteiro 2017 [19]	A comparative analysis of oral and maxillofacial pathology over a 16-year period, in the north of Portugal	Portugal	2017	The Pathology Department of the Hospital de Santo Antonio	Histopathologic evaluation	Patients from the Oporto community	N/A	Biopsies showing normal tissue; repeated biopsies of lesions already diagnosed, unclear or inconclusive cases	N/A	3–100	1. Reactive lesions (21.1%) 2. Cystic lesions (20.1%) 3. Inflammatory lesions (19.8%) 4. Malignant neoplasms (15.0%) 5. Benign neoplasms (12.6%) 6. Premalignant lesions (5.1%) 7. Autoimmune/metabolic lesions (2.8%) 8. Developmental disorders (2.1%) 9. Infective lesions (1.4%)	1. Fibroepithelial polyp (12.0%) 2. SCC (12.0%) 3. Inflammatory odontogenic cyst (8.0%) 4. Pleomorphic adenoma (4.0%) 5. Follicular cyst (3.0%) 6. Squamous cell papilloma (3.0%) 7. Non-specific ulcer (3.0%) 8. Mucocele (3.0%) 9. Chronic sialoadenitis (3.0%) 10. Pyogenic granuloma (3.0%)
Guedes 2015 [20]	Oral soft tissue biopsies in Oporto, Portugal: An eight year retrospective analysis	Portugal	2015	Pathology Department of the Hospital de Santo Antonio	Histopathologic evaluation	Patients at the Pathology Department who underwent oral biopsy between 1999 and 2006	Definitive histopathological diagnosis	Unclear, missing, or inconclusive results	N/A	3–100	1. Reactive lesions (28.3%) 2. Malignant neoplasms (19.6%) 3. Inflammation/infection (15.5%) 4. Benign neoplasms (8.9%) 5. Cystic lesions (6.8%) 6. Autoimmune/metabolic diseases (6.4%) 7. Vascular lesions (4.9%) 8. Normal tissue (3.8%) 9. Hamartomatous/congenital lesions (1.4%)	1. Fibroepithelial hyperplasia (17.9%) 2. Epidermoid carcinoma (15.2%) 3. Mucocele (6.1%) 4. SCC (4.8%) 5. Angiomas/vascular abnormalities (4.6%) 6. Normal tissue (3.8%) 7. Non-specific ulcer (3.7%) 8. Leukoplakia (3.7%) 9. Lichen planus (3.3%) 10. Chronic inflammation (3.2%)
Rivera 2017 [21]	Oral diseases: a 14-year experience of a Chilean institution with a systematic review from eight countries	Chile	2017	University of Talca medical record database	Both	Patients treated at the University of Talca between 2001 and 2014	Availability of both clinical and histopathological diagnoses	N/A	N/A	4–97	1. Soft tissue tumors (23.2%) 2. Epithelial pathology (15.8%) 3. Salivary gland pathology (10.9%) 4. Dermatologic diseases (10.1%) 5. Facial pain and neuromuscular diseases (6.9%) 6. Allergies and immunologic diseases (6.2%) 7. Developmental defects (4.9%) 8. Fungal diseases (4.2%) 9. Pulp and periapical disease (3.2%) 10. Odontogenic cysts and tumors (2.3%)	1. Irritation fibroma (10.2%) 2. Lichen planus (5.8%) 3. Mucocele (5.4%) 4. Burning mouth syndrome (4.5%) 5. Hemangioma (4.1%) 6. Recurrent aphthous stomatitis (4.1%) 7. Papilloma (3.8%) 8. Pyogenic granuloma (3.2%) 9. Melanin pigmentation (2.0%) 10. Nevus (2.0%)
Rivera 2017 [22]	Oral mucosal lesions in a Chilean elderly population: A retrospective study with a systematic review from thirteen countries	Chile	2017	The School of Dentistry, University of Talca	Both	Elderly patients from the oral pathology service	Presence of one clear clinical and histopathological diagnosis,	N/A	277	61–97	1. Soft tissue tumors (28.9%) 2. Epithelial pathology (18.4%) 3. Facial pain and neuromuscular diseases (10.5%) 4. Dermatologic diseases (9.4%) 5. Fungal diseases (6.5%) 6. Physical and chemical injuries (6.1%) 7. Salivary gland pathology (5.8%) 8. Allergies and immunologic diseases (5.4%) 9. Developmental defects (3.6%) 10. Pulp and periapical disease (1.8%)	1. Irritation fibroma (10.8%) 2. Hemangioma (7.2%) 3. Burning mouth syndrome (7.2%) 4. Oral lichen planus (4.3%) 5. Epulis fissuratum (4.3%) 6. Melanin pigmentation (4.0%) 7. Recurrent aphthous stomatitis (4.0%) 8. Vascular malformation (3.2%)
Saleh 2017 [23]	Retrospective analysis of biopsied oral and maxillofacial lesions in South-Western Saudi Arabia	Saudi Arabia	2017	King Fahad Central Hospital histopathology records	Histopathologic evaluation	Patients with oral lesions who attended the surgical biopsy service of King Fahad Central Hospital	All cases with oral lesions between 2006 and 2015	N/A	714	0–100	1. Malignant neoplasm (38.7%) 2. Inflammatory lesions (16.5%) 3. Reactive lesions (13.7%) 4. Non-inflammatory cysts (9.8%) 5. Benign tumors (8.7%) 6. Mucosal pathology (8.1%) 7. Benign odontogenic tumors (2.2%) 8. Miscellaneous lesions (2.1%)	1. Squamous cell carcinoma (36.1%) 2. Pyogenic granuloma/mucocele (7.0%) 3. Mucocele/ranula (7.0%) 4. Epithelial hyperplasia (4.5%) 5. Chronic non-specific inflammation (4.3%) 6. Focal fibrous hyperplasia (2.5%) 7. Radicular cyst (2.2%) 8. Squamous cell papilloma (2.2%) 9. Sialadenitis (1.7%) 10. Pleiomorphic adenoma (1.7%)
Fonseca 2019 [24]	Oral and maxillofacial lesions in older individuals and associated factors: A retrospective analysis of cases retrieved in two different services	Brazil	2019	The Oral Medicine clinic and laboratory service at the Department of Oral Pathology and Surgery of the Federal University of Minas Gerais	Both	Patients aged 60 or older attending the Oral Medicine clinic between 2001 and 2017	N/A	Inadequate information, inconclusive diagnosis	N/A	60	1. Inflammatory/reactive lesion (40.4%/44.2%) 2. Infectious diseases (18.5%/4.2%) 3. Variations in normality (10.8%/2.9%) 4. Potentially malignant disorders (7.4%/13.3%) 5. Malignant neoplasms (7.1%/17.6%) 6. Immunological diseases (5.7%/3.0%) 7. Benign neoplasms (3.4%/5.4%) 8. Non-neoplastic bone lesions (3.1%/1.5%) 9. Pigmented lesions (2.1%/1.4%) 10. Odontogenic/non-odontogenic cysts (1.5%/6.5%) Oral Medicine clinic %/Laboratory %	1. Inflammatory fibrous hyperplasia (24.3/33.6%) 2. Candidiasis/SCC (15.6/15.2%) 3. Varices/leukoplakia (7.2/12.2%)
Da Silva 2019 [25]	Epidemiological study of lesions of the maxillofacial complex diagnosed by UNIME histopathology laboratory, Lauro de Freitas, Bahia	Brazil	2019	Histopathological data from the dental clinics of the Faculty of Agricultural Sciences and Health of the Metropolitan Union of Education and Culture	Histopathologic evaluation	Dental clinic patients from the Lauro de Freitas region	Oral lesions diagnosed and filed between 2003 and 2014	Inadequate diagnosis or information	434	6–87	1. Non-neoplastic proliferative processes (24.2%) 2. Odontogenic cysts (17.5%) 3. Miscellaneous (10.1%) 4. Bone lesions (6.7%) 5. Odontogenic tumors (5.3%) 6. Inflammatory lesions (5.3%) 7. Lesions associated with the root apex (4.8%) 8. Salivary gland lesions (4.4%) 9. Non-odontogenic tumors (3.9%) 10. Malignancies (3.9%)	1. Inflammatory fibrous hyperplasia (13.1%) 2. Radicular cyst (10.8%) 3. N/A
Carvalho 2011 [26]	Epidemiological study of 534 biopsies of oral mucosal lesions in elderly Brazilian patients	Brazil	2011	Oral Pathology Laboratory	Histopathologic evaluation	Elderly Brazilian patients	Aged 60 or over	N/A	534	60–99	1. Non-neoplastic (66.1%) 2. Benign (15.9%) 3. Malignant (10.5%) 4. Potentially malignant (7.5%)	1. Fibrous hyperplasia (19.1%) 2. Chronic inflammation (9.2%) 3. SCC (7.9%) 4. Odontogenic cyst (6.0%) 5. Epithelial dysplasia (5.2%)
Fattori 2019 [27]	Stomatological disorders in older people: An epidemiological study in the Brazil southern	Brazil	2019	Service of Stomatology and Prevention of Oral Maxillofacial Cancer of Sao Lucas Hospital	Both	Elderly patients of a stomatology service in southern Brazil	Older than 60 years	Incomplete information	N/A	60–97	All diagnoses: 1. Variations in normality (44.5%) 2. Local fungal infection (26.1%) 3. Reactive inflammatory lesions (24.6%) 4. Burning mouth syndrome (14.9%) 5. Benign neoplasms (12.4%) 6. Autoimmune diseases (12.3%) 7. Malignant epithelial neoplasms (7.2%) 8. Anemias (4.3%) 9. Salivary gland pathology (2.7%) 10. Odontogenic cysts and tumors (0.9%)	Biopsied cases only: 1. SCC (30.2%) 2. Fibroepithelial hyperplasia (28.2%) 3. Hyperkeratosis and acanthosis (5.0%) 4. Fibrous proliferation (3.0%) 5. Lichen planus (2.5%) 6. Papilloma (2.3%) 7. Pyogenic granuloma (2.3%) 8. Fibroma (2.0%) 9. Peripheral giant cell granuloma (2.0%) 10. Epithelial dysplasia (1.6%)
Akinyamoju 2017 [28]	Audit of Oral Histopathology Service at a Nigerian Tertiary Institution over a 24-Year Period	Nigeria	2017	Oral Pathology laboratory	Histopathologic evaluation	Patients of the Ibadan University Hospital	All biopsies submitted between 1990–2014	Inadequate information, imprecise diagnosis, immunohistochemistry cases	N/A	N/A	1. Reactive lesions: 411 (23.1%) 2. Odontogenic tumors: 321 (18.1%) 3. Epithelial tumors: 220 (12.4%) 4. Salivary Gland tumors: 163 (9.2%) 5. Soft tissue tumors: 159 (8.9%) 6. Fibro-osseous lesions: 149 (8.4%) 7. Pulp and periapical lesions: 120 (6.7%) 8. Cystic Lesions: 70 (3.9%) 9. Heamatolymphoid neoplasms: 56 (3.1%) 10. Salivary gland diseases: 33 (1.9%)	1. Ameloblastoma: 204 (11.5%) 2. SCC: 185 (10.4%) 3. Pyogenic granuloma: 151 (8.5%) 4. Ossifying fibroma: 70 (3.9%) 5. Chronic inflammation: 64 (3.6%) 6. Apical cyst: 61 (3.4%) 7. Apical granuloma: 56 (3.1%) 8. Fibromyxoma 51 (2.9%) 9. Fibroma: 50 (2.8%) 10. Fibrous dysplasia (2.8%)
Soyele 2019 [29]	Concordance between clinical and histopathologic diagnosis and an audit of oral histopathology service at a Nigerian tertiary hospital	Nigeria	2019	Oral Pathology and Diagnosis Units, Obafemi Awolowo University Teaching Hospital Complex	Histopathologic evaluation	Patients with biopsies submitted between 2008–2017	N/A	Lack of clinical impression, ambiguous diagnosis, inadequate information	592	0–94	1. Odontogenic tumors (25.3%) 2. Reactive lesions (12%) 3. Fibro-osseous lesions (10.3%) 4. Epithelial tumors (10%) 5. Cystic lesions (8.8%) 6. Salivary gland pathology (7.5%) 7. Microbial/inflammatory diseases (6.1%) 8. Hemato-lymphoid neoplasms (2.7%) 9. Pulp and periapical lesions (2.5%) 10. Giant cell lesions (2.2%)	N/A
Lei 2014 [30]	Retrospective study of biopsied head and neck lesions in a cohort of referral Taiwanese patients	Taiwan	2014	Oral Pathology Department records	Histopathologic evaluation	Taiwanese patients who received head/neck biopsy between 2000 and 2011	Diagnosed cases	Normal tissues, non-specific findings	37,210	0–99	1. Premalignant lesions (38.7%) 2. Inflammatory/infective lesions (31.6%) 3. Non-odontogenic malignant lesions (16.2%) 4. Odontogenic cysts (6.1%) 5. Benign non-odontogenic tumors (4.4%) 6. Miscellaneous (1.5%) 7. Benign odontogenic tumors (1.2%) 8. Non-odontogenic cysts (0.25%)	1. SCC (13.3%) 2. Hyperkeratosis (12.8%) 3. Epithelial dysplasia (7.8%) 4. Candidiasis (6.8%) 5. Oral submucous fibrosis (6.7%) 6. Epithelial hyperplasia (6.4%) 7. Verrucous hyperplasia (5.0%) 8. Inflammation (4.9%) 9. Radicular cyst (4.6%) 10. Apical granuloma (3.8%)
Sixto-Requeijo 2012 [31]	An analysis of oral biopsies extracted from 1995 to 2009, in an oral medicine and surgery unit in Galicia (Spain)	Spain	2012	The Oral Medicine, Oral Surgery and Implantology unit at the University of Santiago de Compostela	Histopathologic evaluation	Patients of the University of Santiago	All patients who underwent biopsy between 1995 and 2009	Multiple biopsies, missing information	562	5–96	1. Mucosal pathology (37.9%) 2. Odontogenic cysts (27.4%) 3. Connective tissue pathology (13.4%) 4. Salivary gland pathology (5.3%) 5. Periodontal pathology (4.0%) 6. Miscellaneous (3.9%) 7. Malignant tumor (3.9%) 8. Dental pathology (2.8%) 9. Bone pathology (1.1%) 10. Odontogenic tumor (0.5%)	1. Radicular cysts (16.7%) 2. Leukoplakia (15.5%) 3. Lichen planus (14.1%) 4. Fibroma (11.4%) 5. Dentigerous cyst (9.4%) 6. Mucocele (4.3%) 7. Papilloma (3.7%) 8. SCC (3.4%) 9. Periapical granuloma (2.8%) 10. Pyogenic granuloma (2.2%)
Ali 2013 [32]	Prevalence of oral mucosal lesions in patients of the Kuwait University Dental Center	Kuwait	2013	Kuwait University Dental Center	Clinical examination	New patients of the Kuwait University Dental Center admissions clinic	New patients	N/A	530	N/A	1. White lesions (47.7%) 2. Pigmented lesions (20.0%) 3. Exophytic lesions (18.9%) 4. Miscellaneous (5.3%) 5. Red lesions (4.4%) 6. Ulcerative lesions (3.7%)	1. Fordyce granules (20.4%) 2. Linea alba (11.4%) 3. Generalized pigmentation (11.2%) 4. Hairy tongue (5.6%) 5. Leukoedema (5.4%) 6. Frictional keratosis (5.3%) 7. Irritation fibroma (4.9%) 8. Torus/exostoses (3.7%) 9. Fissured tongue (3.3%) 10. Frenal tag (2.5%)
Sofizadeh 2022 [33]	The spectrum and frequency of histopathological diagnosis of oral diseases in Oslo: Implications to oral pathology syllabus	Norway	2023	Department of Pathology, Oslo University Hospital	Histopathologic evaluation	Patients referred to the Department of Pathology between 2015 and 2016	N/A	N/A	N/A	N/A	1. Cysts/granulomas/dental follicles (43%) 2. Benign tumors and reactive lesions (27%) 3. Vesiculobullous lesions (17%) 4. Salivary gland pathologies (7%) 5. Jaw lesions (4%) 6. Malignant tumors (1%) 7. Pigmented lesions (1%) 8. Odontogenic tumors (1%)	1. Periapical granuloma (16%) 2. Fibromas (12%) 3. Radicular cysts (12%) 4. Dentigerous cysts (8%) 5. Mucocele (4%) 6. Lichen planus (4%) 7. Hyperplastic dental follicles (3%) 8. Papilloma (3%) 9. Odontogenic keratocysts (2%) 10. Osteonecrosis of the jaw (2%)
Poudel 2019 [34]	Clinicopathological Analysis of Oral Lesions-A hospital based retrospective study	Nepal	2019	The Department of Oral Pathology, Dhulikhel Hospital	Histopathologic evaluation	Patients in the central east of Nepal	All diagnosed oral lesions between January 2016 and December 2017	Insufficient clinical details, inconclusive biopsies, salivary gland lesions	237	2–85	1. Odontogenic cysts (20.7%) 2. Benign lesions (17.3%) 3. Malignant lesions (16.9%) 4. Non-odontogenic cyst/pseudocyst (14.7%) 5. Reactive lesions (8.0%) 6. Miscellaneous (7.4%) 7. Odontogenic tumor (5.0%) 8. Premalignant lesions (2.0%)	1. Mucocele (13.1%) 2. SCC (12.7%) 3. Fibroma (8.0%) 4. Pyogenic granuloma (7.6%) 5. Radicular cyst (7.6%) 6. Odontogenic keratocyst (6.3%) 7. Dentigerous cyst (5.5%) 8. Ameloblastoma (4.2%) 9. Periapical granuloma (3.4%) 10. Hemangioma (3.0%)
Moridani 2015 [35]	A 7-year retrospective study of biopsied oral lesions in 460 Iranian patients	Iran	2014	The Oral and Maxillofacial department of the Islamic Azad University	Histopathologic evaluation	Patients and referrals from North-East Tehran	N/A	N/A	460	3–89	1. Reactive lesions (21.5%) 2. Odontogenic cysts (17.4%) 3. Pulp and periapical lesions (15.6%) 4. Immune-mediated lesions (5.4%) 5. Bone pathology (5.0%) 6. Odontogenic tumors (5%) 7. Epithelial lesions (3.9%) 8. Salivary gland diseases (2.0%) 9. Malignant epithelial tumors (1.5%) 10. Benign mesenchymal tumors (1.5%)	1. Odontogenic keratocyst (7.4%) 2. Radicular cyst (7.4%) 3. Irritation fibroma (6.3%) 4. Dentigerous cyst (5.4%) 5. Periapical granuloma (5.4%) 6. Lichen planus (4.3%) 7. Epulis fissuratum (4.1%) 8. Pyogenic granuloma (3.3%) 9. Ameloblastoma (3.0%) 10. Residual cyst (2.2%)
Kalantari 2022 [36]	A Survey of Oral and Maxillofacial Biopsies Over a 23-year Period in the Southeast of Iran	Iran	2022	Department of Oral and Maxillofacial Pathology, Kerman Faculty of Dentistry	Histopathologic evaluation	Patients referred to the Department of Oral and Maxillofacial Pathology	Biopsies taken between July 1997 and July 2020	Normal tissue present, indefinite diagnosis, repeated biopsy	N/A	0–105	1. Reactive lesions (34.6%) 2. Immune-mediated (20.7%) 3. Odontogenic cysts (12.6%) 4. Tooth and periodontal-related lesions (4.4%) 5. Inflammatory and infectious lesions (3.1%) 6. Osseous lesions (2.4%) 7. Salivary gland lesions (2.4%) 8. Pigmented lesions (2.3%) 9. Non-odontogenic cysts (0.5%)	1. Lichen planus (18.1%) 2. Pyogenic granuloma (10.1%) 3. Irritation fibroma (9.6%) 4. Radicular cyst (7.6%) 5. Peripheral ossifying fibroma (4.0%) 6. SCC (3.9%) 7. Hyperkeratosis (3.7%) 8. Periapical granuloma (3.4%) 9. Epulis fissuratum (3.4%) 10. Dentigerous cyst (2.9%)
Kelloway 2014 [37]	A retrospective analysis of oral and maxillofacial pathology in an Australian adult population	Australia	2014	The University of Queensland Oral Pathology Service	Histopathologic evaluation	Patients of the Oral Pathology service	Patients 17 years of age or older	Lack of age, inconclusive diagnosis	N/A	N/A	1. Mucosal pathology (37.2%) 2. Odontogenic cyst (16.3%) 3. Dental pathology (14.5%) 4. Gingival and periodontal pathology (7.6%) 5. Miscellaneous pathology (7.4%) 6. Bone and TMJ pathology (3.8%) 7. Salivary gland pathology, excluding tumors (2.9%) 8. Malignant tumors (2.7%) 9. Odontogenic tumors and hamartomas (2.6%) 10. Normal tissue (2.2%)	1. Fibrous hyperplasia (15.2%) 2. Chronic periapical granuloma (9.6%) 3. Radicular cyst (9.5%) 4. Dentigerous cyst (4.1%) 5. Fibroepithelial polyp (4.0%) 6. Squamous papilloma (2.8%) 7. Fibrous epulis (2.7%) 8. Fibrous hyperplasia (2.5%) 9. Normal tissue (2.2%) 10. Pyogenic granuloma (2.1%)
Singh 2021 [38]	A Retrospective Study to Evaluate Biopsies of Oral and Maxillofacial Lesions	Turkey	2021	Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Kocaeli University	Histopathologic evaluation	Patients who attended the Faculty of Dentistry over 2014–2018	N/A	N/A	475	7–88	1. Odontogenic cysts (71.6%) 2. Bone tumors (15.8%) 3. Odontogenic tumors (10.9%) 4. Malignancies (1.7%)	1. Radicular cysts (45.5%) 2. Dentigerous cysts (16.2%) 3. Giant cell granulomas (7.4%) 4. Odontogenic keratocysts (4.8%) 5. Nasopalatine duct cyst (4.6%) 6. Odontoma (4.0%) 7. Ossifying fibroma (3.8%) 8. Pyogenic granuloma (3.2%) 9. Osteoma (2.9%) 10. Ameloblastoma (1.9%)

). Among the studies included, the most consistent and structured diagnostic groupings were observed in those that used the classification system from Neville et al. or the WHO Guide for the Diagnosis of Oral Diseases. These frameworks allow for clearer categorization and comparison of lesion types. However, many studies have used self-defined or inconsistent categories, contributing to the overall heterogeneity of the dataset.

Regional differences were not distinctly observed; most studies from the Middle East, Europe, and South America consistently reported mucosal lesions, particularly reactive or non-neoplastic conditions, as among their most frequently encountered diagnostic categories. Due to the substantial variability in study design, terminology, and classification systems, a formal meta-analysis was not feasible.

Overall, 46 unique diagnostic categories of oral lesions were used across all studies. To contextualize the results of the systematic review with our own data, the 10 most frequent diagnostic categories and specific diagnoses across all studies were used for comparison. The most prevalent diagnostic category was malignant tumors, with 64% of studies reporting it as one of the ten most frequent categories. This was followed by salivary gland pathology, noted in 54% of studies, and benign neoplasms and reactive lesions, found in 46% of studies. Both immunologic lesions and odontogenic tumors were found in 39% of the studies included, while cystic lesions and odontogenic cysts were found in 35%, followed by epithelial pathology and infectious diseases in 25% of the literature. The specific lesions most highly noted across the literature were squamous cell carcinoma and pyogenic granuloma, with both reported as one of the 10 most frequent diagnoses in 54% of studies. This was followed by radicular cysts, lichen planus, and fibromas, which were all reported in 43% of the papers included. Figure 3 illustrates the full breakdown of the most common diagnostic categories and specific pathologic entities across 28 published papers. The bar graphs indicate the number of studies that found a specific diagnostic category or diagnosis as being one of the 10 most frequent, i.e., 18 studies found malignant tumors that were between the 1st and 10th most common pathology.

3.2. Retrospective Study—Analysis of Oral Pathology Data

Using the three search methods described earlier, we identified a total of 524 patients in the AxiUm database who presented to the clinic with oral lesions during the last 10 years. The age range of patients was 5–100 years old, with the highest proportion of patients between the ages of 70 and 79 (Figure 3). These 524 patients displayed a total of 1065 distinct pathologies. The most common clinical diagnostic category was developmental defects, with 283 cases (26.6%) noted. This was followed by epithelial pathology with 232 cases (21.8%) and physical and chemical injuries with 196 cases (18.5%). More specifically, the five most common clinical diagnoses were coated tongue (5.8%), leukoplakia (5.1%), oral lichen planus (4.5%), amalgam tattoo (3.5%), and Fordyce granules (3.5%).

Table 2. Diagnostic categories encountered clinically, grouped by frequency.

Category	N	Relative Frequency
a. Developmental defects	283	26.6%
b. Epithelial pathology	232	21.8%
c. Physical and chemical injuries	196	18.5%
d. Dermatologic diseases	96	9.0%
e. Soft tissue tumors	88	8.3%
f. Immunologic disease	49	4.6%
g. Infectious disease	47	4.4%
h. Salivary gland pathology	26	2.5%
i. Periodontal disease	13	1.2%
j. Bone pathology	13	1.2%
k. Pulpal and periapical disease	9	0.8%
l. Developmental cyst	7	0.7%
m. Facial pain and neuromuscular disorders	3	0.2%
n. Oral manifestations of systemic conditions	2	0.2%
Total	1065	100%

illustrates the prevalence of all 12 diagnostic categories from the clinical stream.

From the biopsied stream, a total of 107 patients had biopsies conducted, resulting in the diagnosis of 406 distinct pathologies. Of these, the most common diagnosis was epithelial atypia, with 37 cases (9.11%), followed by hyperorthokeratosis, with 36 cases (8.87%), and mild to moderate epithelial dysplasia, with 35 cases (8.62%). A full breakdown of all histopathological diagnoses is available in

Table 3. Histopathological diagnoses from the biopsied stream (superscript letters indicate category—refer to Table 2).

Diagnosis	Number	Frequency	Diagnosis	Number	Frequency
Epithelial atypia b	37	9.11%	Acute inflammation c	2	0.49%
Hyperorthokeratosis b	36	8.87%	Subepithelial clefting f	2	0.49%
Epithelial dysplasia (mild to moderate) b	35	8.62%	Ulcerative granuloma c	1	0.25%
Hyperkeratosis b	29	7.14%	Stromal eosinophilia c	1	0.25%
Chronic inflammation b	25	6.16%	Spongiosis b	1	0.25%
Acanthosis b	24	5.91%	Reactive chronic inflammatory infiltrate c	1	0.25%
Epithelial atrophy b	19	4.68%	Psoriasiform mucositis d	1	0.25%
Hyperparakeratosis b	15	3.69%	Polyclonal plasmacytic inflammation c	1	0.25%
Lichenoid mucositis d	11	2.71%	Pleomorphic adenoma h	1	0.25%
Lichenoid inflammation d	11	2.71%	Phlebolith a	1	0.25%
Candidiasis g	10	2.46%	Peripheral giant cell granuloma c	1	0.25%
Chronic mucositis d	10	2.46%	Parulis k	1	0.25%
Squamous papilloma g	9	2.22%	Papillary hyperplasia c	1	0.25%
Irritation fibroma c	8	1.97%	Osteitis c	1	0.25%
Ulceration c	7	1.72%	Organizing thrombus a	1	0.25%
SCC b	6	1.48%	Neurofibroma e	1	0.25%
MMP d	6	1.48%	Nasopalatine duct cyst l	1	0.25%
Focal fibrous hyperplasia c	6	1.48%	Melanosis b	1	0.25%
Verrucous carcinoma b	5	1.23%	Lymphoid stroma c	1	0.25%
Varix a	5	1.23%	Lymphoid hyperplasia c	1	0.25%
Dysplasia (severe) b	5	1.23%	Lymphoid aggregate with follicle c	1	0.25%
Verrucous hyperplasia b	4	0.99%	Hypergranulosis b	1	0.25%
Sialadenitis h	4	0.99%	Hemorrhage c	1	0.25%
Inflammatory fibrous hyperplasia c	4	0.99%	Granulomatous inflammation f	1	0.25%
Pyogenic granuloma c	3	0.74%	Giant cell fibroma c	1	0.25%
Interface mucositis d	3	0.74%	Frictional trauma b	1	0.25%
Granulation tissue c	3	0.74%	Focal abscess k	1	0.25%
Foreign body reaction c	3	0.74%	Fibrous tumor e	1	0.25%
Actinic cheilitis b	3	0.74%	Fibroblast atypia e	1	0.25%
Oral fibroma c	2	0.49%	Fibroepithelial polyp c	1	0.25%
Mucocele h	2	0.49%	Exogenous foreign material c	1	0.25%
Melanotic macule b	2	0.49%	Epithelial proliferation b	1	0.25%
Lichen Planus f	2	0.49%	Chronic periodontitis i	1	0.25%
Hyperplastic squamous mucosa b	2	0.49%	Cauterization artifact c	1	0.25%
Fungal infection g	2	0.49%	Benign salivary gland tumor h	1	0.25%
Chronic ulcer c	2	0.49%	Benign salivary gland lobuli h	1	0.25%
Carcinoma in-situ b	2	0.49%	Atypical epithelial proliferation b	1	0.25%
Bone sequestrum j	2	0.49%	Amalgam tattoo c	1	0.25%
Bacterial infection g	2	0.49%
		Total	406

.

4. Discussion

4.1. Systematic Review Key Points

Various categorization systems were used in the 28 studies included. Many studies classified lesions based on previous categories used in research by Jones and Franklin [6,37,39]. Other studies based their system on the International Classification of Diseases, Dentistry and Stomatology (ICD-11) or the WHO Guide for diagnosis of oral diseases [40,41,42]. Some used the textbook by Neville et al. to group their identified lesions [10], while others came up with completely novel self-identified categories [43,44]. Some publications included no diagnostic groupings whatsoever [45,46]. Notably, studies using standardized systems demonstrated more consistent reporting of lesion types, suggesting their utility for future research and educational calibration.

Malignant tumors, for instance, which was the most prevalent category extracted from our systematic review [23,47], could fit into multiple categories of our proposed system, e.g., soft tissue tumors, epithelial pathology, salivary gland pathology, bone pathology, etc. However, the originating tissue of a given malignant tumor (salivary gland vs. bone, for instance) is emphasized when our suggested system is enforced, which brings the advantage of subcategorization and better specificity.

While there is certainly some overlap between the literature in terms of how oral lesions are classified, the heterogeneity makes any direct comparisons between global research studies difficult. To that end, a definitive set of diagnostic categories that could be used worldwide would improve the comparability of results in future research. Currently, categories are too broad, e.g., ‘benign lesions’, or ambiguous, i.e., whether leukoplakia is classified as a premalignant lesion or epithelial pathology; this limits the ability of clinicians/researchers/professors to apply the results of the research to their own practice and classroom. No clear regional variation was identified across the studies included. Mucosal lesions, especially those classified as reactive or non-neoplastic, were consistently among the most prevalent diagnostic categories in studies from the Middle East, Europe, and South America.

From this review of the literature, it is highly evident that there is a lack of standardization in terminology for diagnostic categories and even for specific oral lesions. Standardization in terminology across North America, at a minimum, would allow for clearer communication between referring dentists and specialists in the future.

4.2. Retrospective Study Comparison to Literature and Important Takeaways

Our analysis of oral pathology data from the University Dental Clinic database search showed developmental defects and epithelial pathologies to be the two most common diagnostic categories. Developmental defects were indeed noted as being one of the most common clinical diagnoses in other studies, which aligns with our study [48,49]. Also, the high rate of epithelial pathologies observed in our study matches with other studies conducted worldwide [6,11,50]. However, further direct comparison to the literature is difficult due to the lack of standardization in methodology and diagnostic categories.

Moreover, some discrepancies between our study and the current literature may be explained by the fact that other studies examined only cases sent for histopathological analysis, while we examined clinically diagnosed cases as well. The fewer instances of non-malignant pathologies observed in our data follow logically from the idea that clinicians may use solely clinical examination for a suspected benign/reactive/developmental lesion, with biopsies being conducted only in the context of a potential malignant lesion [51]. As such, the dental clinic data we examined would have documented all oral lesions, including benign, premalignant, and malignant, leading to differing results from studies that purely examined biopsies from a strongly suspected malignancy. Also, the observed differences in lesion prevalence between our local dataset and the global literature may reflect variations in biopsy referral practices, diagnostic thresholds, and educational priorities across institutions, with developmental defects being more frequently documented in teaching clinics where comprehensive clinical examination is emphasized over histopathological confirmation.

Our findings have highlighted several challenges that can be encountered during the diagnosis and treatment of oral and maxillofacial diseases. To date, there are some lesions that lack a consensus on both diagnosis and care. Odontogenic keratocysts, for instance, are currently placed under the odontogenic cyst category, but were previously classified as benign aggressive neoplasms (keratocystic odontogenic tumors [KCOT]) in the recent past [52]; that change has an impact on the prevalence and epidemiology of odontogenic tumors [53] and may affect the subsequent treatment decisions for such lesions. Ameloblastoma, for instance, is an odontogenic tumor for which treatment can range from complete surgical resection to more conservative management, such as enucleation; these varying approaches have a wide range of patient outcomes and recurrence rates [54] and may leave both patients and providers unclear on the best way to approach such conditions.

The lack of congruent standards for the identification and grouping of oral diseases—as evidenced by the many diagnostic categories found in the literature—has made it more difficult to achieve a universal standard of care. Building up on that topic, certain oral lesions go by multiple names, e.g., inflammatory fibrous hyperplasia, which may also be fibrous epulis, denture epulis, focal fibrous hyperplasia, or fibroepithelial polyp. This is compounded by the fact that terms seen as outdated need to be replaced with updated terminology [55]. While it is necessary to alter nomenclature that is grossly inappropriate, this constant addition and subtraction of oral pathology terms may lead to increased confusion for practitioners.

Other illustrative examples of imprecise nomenclature are irritation fibroma and pyogenic granuloma, which are very common reactive lesions of the oral cavity; the etymology of the suffix “oma” derives from Ancient Greek and is widely used for mostly benign and sometimes malignant neoplasia. Nevertheless, being a truly reactive lesion, irritation fibroma represents none of those. Pyogenic, on the other hand, literally means “producing pus”, whereas granuloma is a term mostly reserved for diseases presenting with a granulomatous pattern of inflammation; In contrast, a pyogenic granuloma neither produces pus nor is associated with granulomatous inflammation.

5. Conclusions

This is the first study to report the diagnostic frequency of oral lesions at a specific dental school in Canada. While our initial goal was to compare these findings with those from other institutions through a systematic review, the lack of consistent terminology and classification frameworks across studies limited the extent of meaningful comparison. This inconsistency highlights a critical educational challenge: the absence of a standardized categorization system for oral lesions. Such standardization is essential not only for improving diagnostic calibration among students and clinicians, but also for enhancing the clarity and effectiveness of oral pathology education. We propose that the development and adoption of a referenced sorting framework could serve as a valuable tool in dental curricula, supporting both clinical instruction and research comparability across institutions. For instance, as a concrete example in a clinical teaching scenario, students could be assessed on their ability to correctly classify a lesion such as leukoplakia under ‘epithelial pathology’ rather than ‘premalignant lesions,’ thereby reinforcing diagnostic precision and aligning their reasoning with standardized terminology used in clinical practice, such as aligning diagnostic categories with case-based learning modules and OSCE assessments. We acknowledge that this proposal is based on a limited empirical dataset. The findings are drawn from a single institution, and the sample size, while informative, may not be fully representative of broader populations. The scope of the data reflects the specific clinical and educational environment of one teaching clinic, which may differ from other settings in terms of patient demographics and case complexity. Additionally, limitations include potential diagnostic bias due to variability in clinician experience, incomplete or inconsistent record-keeping within the electronic database, and language or publication bias in the systematic review, which may have excluded relevant studies not published in English or indexed in the selected databases. These limitations highlight the need for further multi-institutional studies to validate and refine any proposed cataloguing system. Future research should also explore how such frameworks can be effectively integrated into dental curricula to enhance learning outcomes and clinical preparedness.