Oral — Health, Diseases, Therapies, and Technologies

Purpose: We aimed to systematically review the current literature on the bond strength between custom tray materials and impression materials, including the various parameters affecting the strength. Methods: Four electronic databases were used: Ovid, Web of Science, PubMed, and Scopus. Relevant studies were chosen based on their eligibility, determined through inclusion and exclusion criteria. This review followed the PRISMA strategy. A risk of bias assessment was produced to evaluate the validity of each study. Results: There were 173 initial relevant studies identified, and after the screening process, this was reduced to seven. Two additional studies were also included from hand searching, resulting in total nine studies to be included in the review. Four of the nine evaluated studies concerned additively manufactured (AM) materials, including acrylonitrile butadiene styrene (ABS), polyethylene terephthalate glycol polyester (PETG), high-impact polystyrene (HIPS), and polylactic acid (PLA). Five studies evaluated an auto-polymerizing resin and one a thermoplastic material. All studies used polyvinyl siloxane impression materials and an adhesive selection following manufacturers’ recommendations. Three studies used scanning electron microscopy (SEM) to analyze their specimens. All studies reported a low risk of bias. Conclusions: Surface roughening was shown to reduce the strength of the bonding interface, whereas combining chemical and mechanical retention was shown to increase the bond strength. Inconsistent results exist in determining if AMed (3D-printed) tray materials are comparable or perform better than the conventional tray materials, highlighting the need for further study. Clinical Significance: The bond strength of the custom tray to the dental impression material is critical as it affects the model produced and therefore the final prosthesis. It is therefore invaluable to use materials with high bond strength for the construction of custom trays. Full article

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. Full article

Peri-implantitis is marked by ongoing bone loss and soft tissue inflammation surrounding dental implants. Due to its ability to intensify tissue healing and its compatibility with the body, hyaluronic acid (HA) has appeared as a viable biomaterial for managing this oral condition. The goal of this scoping review is to examine current trends and future directions for refining HA-based interventions as an adjuvant peri-implant therapy over the past decade. Using the PRISMA-ScR guidelines, a review of the literature for the past 10 years was conducted. Articles related to HA’s anti-inflammatory, antimicrobial, regenerative mechanisms were taken into consideration to underline both achievements and research related to peri-implantitis treatment management. A total of 105 articles were found, and finally, five clinical studies were included. Despite encouraging results that showed good efficacy of HA use as an adjuvant and/or preventive therapeutic agent for peri-implantitis treatment, a larger number of randomized controlled trials and standardized protocols are needed to confirm HA’s therapeutic efficacy and establish its place in routine clinical practice. Full article

Background: Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by hyperandrogenism, irregular ovulation, and polycystic ovarian morphology. The severity of periodontal inflammation in PCOS may be linked to elevated levels of inflammatory mediators, like interleukins (IL-6, IL-17), and matrix metalloproteinase-8 (MMP-8), found in both serum and saliva samples. This systematic review aims to assess the presence, nature, and variations in salivary inflammatory biomarkers in individuals with PCOS and their potential connection to periodontal disease (PD). Materials and Methods: Selected databases were PubMed, Scopus, Google Scholar, and Web of Science. The search strategy included the following terms: “oral inflammatory biomarkers”, “Salivary mediators,” “metabolic indicators,” “periodontal diseases,” “periodontitis,” “polycystic ovary syndrome,” “PCOS,” and “ovulatory dysfunction.” Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. Results: Several salivary inflammatory biomarkers are present in women with PCOS, including cytokines, C-reactive protein (CRP), reactive oxygen species (ROS), MMPs, and microbial diversity alterations. Additionally, the reviewed studies suggest a correlation between PCOS and PD, as patients with PCOS exhibit greater periodontal alterations compared to healthy women. The heightened periodontal response in PCOS appears to be associated with a systemic inflammatory state, probably increasing the susceptibility to PD. Conclusions: Salivary inflammatory biomarkers in PCOS patients are a useful diagnostic tool for evaluating the heightened risk of periodontal disease. Further research with stricter protocols is necessary to better define the diagnostic potential of these biomarkers for PCOS patients and determine their role in the early detection of periodontal disease. Full article

All forms of life on Earth are dependent on microbes. In vertebrates, the oral cavity and the gastrointestinal tract are colonized by large numbers of microorganisms, which includes species from many life forms: bacteria, fungi, archaea, and protozoa; this collection of microorganisms are commonly referred to as the microbiome. This article reviews the literature, providing a summary of oral and gastrointestinal microbial composition in health and during various disease states. Interactions are explored between microbes in the oral cavity and gastrointestinal tract. This study explores the influence of changed diet, lifestyle, and living conditions in order to examine the link between the oral and gastrointestinal microbiome and changes in their composition, and how this may affect human health. This study also investigates potential microbiome dysbiosis and disease causation in the space environment. The role of prebiotics, probiotics and postbiotics in oral health is discussed, with extension into the unexplored territory of probable oral and gastrointestinal bacterial population changes during long-duration (exportation class) space missions (ECSM). Full article

Background/Objectives: Emotional fear memories are increasingly recognized as contributors to the development of specific fears and phobias. Despite this, relatively little dental fear research has specifically focused on patient memories or their potential role in the etiology of dental fear. Methods: This two-study paper employs qualitative thematic analysis of memories for dental visits among traumatized patients (study 1) and the general patient population (ranging from endorsing no dental fear to severe fear). Recollections were evaluated based on the characteristics (i.e., sensory descriptors, affectively laden, intrusive) of emotional fear memories (studies 1 and 2) and according to a modified cognitive vulnerability model of dental fear (study 2). Results: Characteristics of emotional fear memories were ubiquitous across recollections of individuals who endorsed traumatic dental visits in childhood. Among the general patient population, these characteristics and cognitive vulnerability themes (particularly perceptions of the visit and dentist as dangerous and untrustworthy) were more prevalent in the earliest remembered visits for fearful individuals. When individuals were asked to recall their worst dental visits, emotional fear memory characteristics and vulnerability perceptions were evident across the spectrum of current fear (none to severe). Conclusions: This study contributes to nascent work examining memory in specific fears and phobias and suggests that worst recollections across a general sample share many of the characteristics that might otherwise imply vulnerability for anxiety. We recommend that dental practices universally screen patients for fear, inquire about past negative experiences, partner with patients to minimize evoking their specific vulnerabilities, and diligently implement these personalized care plans. Full article

Background: Periodontal disease is a common chronic inflammatory disease affecting the oral cavity involving the tissues supporting teeth. It is a significant oral health concern worldwide, particularly amongst individuals living with human immunodeficiency virus (HIV). Biological aging is associated with a natural decline in the immune system, which can also affect the severity of periodontitis and other potential risk factors. In people living with HIV (PLWH), the contribution of both the HIV infection and the aging process can lead to increased susceptibility to periodontal disease. Objectives: This paper aims to review the recent literature about the relationships between HIV infection and early aging and their impact on periodontitis, and to inform interested clinicians about the current literature on the intersection between and within these topics. Methods: This review explores the recent literature on the complex relationship between HIV, aging, and periodontitis. The PubMed, ScienceDirect, and Medline databases were used to find clinical research studies within the last 10 years to identify significant correlations between HIV, aging, and periodontitis. Results: These studies identify key pathogens, molecules, or cellular pathways that contribute to a more comprehensive understanding of the pathophysiologic processes that link HIV, aging, and periodontitis. This complex relationship is multifactorial, involving immune dysfunction, microbial dysbiosis, and inflammatory pathways that still need further research. Conclusions: Overall, this exploration through molecular and cellular mechanisms underlying the relationships between aging, HIV, and periodontitis can provide therapeutic implications for dental clinicians to prevent and treat their affected patients. Full article

Objective: This systematic review and meta-analysis aimed to evaluate the effects of moisture control strategies (including wet-bonding techniques, universal adhesives, and etching type) on dentin bonding performance in restorative dentistry. Methods: A comprehensive literature search was conducted across PubMed, Scopus, and Google Scholar, following PRISMA guidelines. Only in vitro and ex vivo studies comparing wet- and dry-bonding protocols, using human dentin substrates, and reporting microtensile bond strength (μTBS) were included. The data were synthesized using a random-effects meta-analysis and the methodological quality was assessed using the MINORS tool. Certainty of evidence was evaluated using the GRADE framework. Results: Nine studies met the inclusion criteria, eight of which were included in this meta-analysis. The moisture control strategies significantly influenced the bonding outcomes, with ethanol and acetone wet bonding yielding higher μTBS and enhanced hybrid layer morphology. The universal adhesives performed effectively under both moist and dry conditions, although their performance varied by the adhesive composition and solvent system. The meta-analysis revealed a statistically significant advantage for hydrated dentin (SMD = +1.20; 95% CI: 0.52 to 1.86; p < 0.001), with the moist and ethanol-treated substrates outperforming the dry and over-wet surfaces. The long-term durability was better preserved with ethanol and acetone pretreatments and the adjunctive use of chlorhexidine. Conclusions: Moisture conditions influence dentin bond strength, but modern universal adhesives show consistent bonding performance across different moisture conditions. Solvent-wet-bonding protocols, particularly with ethanol or acetone, enhance the immediate and long-term performance. While the current evidence is limited by the in vitro designs and heterogeneity, the findings demonstrate protocol flexibility and highlight strategies to optimize adhesion in clinical practice. Future clinical trials are necessary to validate these approaches under real-world conditions. Full article

Background: Mandibular advancement devices (MADs) are considered an effective therapeutic option for managing obstructive sleep apnea syndrome (OSAS) in adults. Obstructive sleep apnea (OSA) is associated with a range of comorbidities, notably cardiovascular disease. The aim of the present retrospective study is to evaluate respiratory and cardiovascular parameters in OSA patients treated with a MAD. Methods: A total of 64 adults with OSA from moderate-to-severe OSAS underwent split-night polysomnography (SN-PSG) at baseline (T0) and after three months of treatment with a MAD (T1) and were subsequently analyzed using statistical methods for a comparative evaluation. Results: After 3 months of treatment, patients showed a significant decrease in mean heart rate (p < 0.05), maximum heart rate (p < 0.01) and in both the AHI and ODI (p < 0.01), along with a significant increase in minimum heart rate (p < 0.05).Conclusions: These findings indicate that MAD therapy may contribute to improvements in both respiratory efficiency and cardiovascular function in individuals with OSAS, offering a valuable integrated treatment strategy for patients with coexisting cardiovascular conditions. Full article

Background: Obesity and periodontitis are two chronic inflammatory diseases with a bidirectional relationship possibly mediated by microbial and immunologic signaling pathways. This narrative review aims to investigate how microbial dysbiosis and inflammation link these diseases, focusing on the interactions between the oral and gut microbiomes. Materials and methods: Peer-reviewed studies (2015–2024) from PubMed, MEDLINE, Ovid and Google Scholar were selected for their relevance to microbial dysbiosis and inflammation, prioritizing clear methodology. Non-peer-reviewed sources or studies lacking microbial/inflammatory data were excluded. Conflicting results and methodological differences, including sampling and study design, were assessed qualitatively on the basis of coherence and methodological rigor. Results: Obesity has been shown to significantly alter the composition of the oral microbiome, characterized by reduced diversity and an increased Firmicutes/Bacteroidetes ratio. At the same time, periodontal pathogens such as Porphyromonas gingivalis can invade the gut, impair barrier function and promote systemic inflammation. Both diseases share common inflammatory pathways involving adipokines and immune-system dysregulation, creating a feedback loop that exacerbates disease progression in both conditions. Obesity also appears to impair the effectiveness of conventional periodontal treatments. Conclusions: The microbial axis between the oral cavity and the gut represents a central pathway in the complex interactions between obesity and periodontitis. This relationship involves microbial dysbiosis, bacterial translocation and shared inflammatory mechanisms that collectively contribute to disease progression. Clinical relevance: A better understanding of the relationship between obesity and periodontitis supports the development of customized treatment strategies for obese patients with periodontal disease. Future research should focus on developing targeted interventions that address both conditions simultaneously to improve patient outcomes and develop more effective prevention and treatment strategies. Full article

Background: The purpose of alveolar ridge preservation (ARP) is to minimise the physiological alveolar ridge reduction occurring after dental extraction, which can prevent the need for future alveolar ridge augmentation. Biologic materials (biologics) promote tissue regeneration based on their effect on wound healing at a cellular level. By integrating biologics into ARP biomaterials, there is a potential to enhance the regeneration of both hard and soft tissues with greater efficacy. Aim: This narrative review aims to evaluate the clinical efficacy of the addition of biologics to existing ARP materials on the physiological changes following ARP of an extraction site. Methods: A search of the PubMed electronic database was conducted, and relevant articles were examined. Sixty-three articles met the inclusion and exclusion criteria and were included in this review. Results and Conclusions: A review of the existing literature found that the combination of biologics with ARP materials resulted in similar dimensional changes when compared to using ARP materials alone. Existing research has identified an enhancement in bone density, increased wound healing capacity of soft and hard tissue, and a reduction in post-operative pain. Whilst the addition of biologics to ARP materials has shown an increase in bone density, its effectiveness in improving implant outcomes and reducing the need for future alveolar ridge augmentation is unclear. Recognising the limitations within the existing literature, along with the risk of bias and heterogeneity, renders it unwise to make definite conclusions about the benefits of integrating biologics with ARP materials. This narrative review found possible benefits in the use of biologics in ARP to optimise patient-related and treatment outcomes, indicating the need for additional research. Full article

Background/Objectives: Brown tumors are bone manifestations of hyperparathyroidism, and they are characterized by histologic similarities with Central Giant Cell Granuloma (CGCG). Their diagnosis requires clinical, microscopic, macroscopic, and serologic correlation, as there is usually an elevation in parathormone levels due to the underlying metabolic disorder. Methods: This case describes a patient with a left mandibular lesion and a history of CGCG. Results: Through the joint analysis of clinical, histologic, and serologic findings, the diagnosis of a brown tumor associated with hyperparathyroidism was confirmed. Conclusions: This case highlights the importance of a comprehensive evaluation of oral and systemic features for accurate diagnoses and appropriate patient management. Full article

Background: Newborns with Pierre Robin Sequence (PRS) usually show varying degrees of upper airway obstruction and difficulty feeding due to severe micrognatia. Mandibular distraction osteogenesis has become popular as an alternative treatment option when other medical or surgical techniques are unsatisfactory. The aim of this study is to test a three-dimensional (3D) cephalometric method in computed tomography (CT) to measure effective mandibular and midface length, and maxillomandibular ratio (Md/Mx ratio), as a mode of growth normalization expression in PRS patients before and after Fast and Early Mandibular Osteo-distraction (FEMOD), for assessing the diagnostic method and the efficacy of surgical treatment. Methods: In this retrospective pilot study, six PRS patients treated via the FEMOD surgical protocol were included. The measurements of effective maxillary and mandibular length were performed on 3D reconstructions from pre-surgical (T1) and post-surgical CT (T2). The growth disparity between the mandible and the maxilla was verified in T1 and was compared with the measurements obtained from the adaptation of the McNamara Norms; the correction of growth disproportion after FEMOD was assessed. Results: In T1, the PRS patients’ mandibular length and the Md/Mx ratio were smaller than the expected mandibular length (p = 0.029) and the expected Md/Mx ratio (p = 0.028). In T2, the PRS patients’ mandibular length and the Md/Mx ratio did not show significant differences from the expected results (p = 0.461 and p = 0.400). Conclusions: The 3D cephalometric analysis identifies the disproportion in pre-surgical maxillomandibular growth between PRS and reference measurements, and demonstrates that FEMOD allows the achievement of proportionality in the growth of the maxillomandibular complex in PRS patients. Full article

Objectives: Ameloblastoma is a locally aggressive odontogenic tumor of the jaws characterized by a high recurrence rate. This work aims to present our clinical experience in managing patient oral rehabilitation following an extensive mandibular ameloblastoma, with a specific focus on mandibular reconstruction using a fibula free flap, followed by dental implant placement and prosthetic rehabilitation in a female patient. Additionally, we provide a comprehensive review of the current evidence on surgical management, reconstruction techniques, and long-term outcomes in ameloblastoma treatment. Methods: A 44-year-old female patient presented with a painless swelling in the left mandible. Orthopantomography (OPG) and computed tomography (CT) demonstrated a well-defined radiolucent lesion extending from the canine to the second premolar. An incisional biopsy was performed, and histopathological examination confirmed the diagnosis of mandibular ameloblastoma. The patient underwent segmental resection of the left mandibular body, followed by immediate reconstruction using a vascularized fibular free flap. Eighteen months postoperatively, four dental implants were placed. One implant failed during the osseointegration phase and was removed. Due to residual hard and soft tissue deficiency, prosthetic rehabilitation was achieved with a metal-reinforced resin overdenture, restoring both function and aesthetics. Results: At the three-year follow-up, clinical and radiographic examinations revealed no evidence of tumor recurrence. The patient remained asymptomatic, reporting neither pain nor functional discomfort. Prosthetic rehabilitation with the metal-reinforced resin overdenture was successfully completed, achieving satisfactory masticatory function and aesthetics. Conclusions: The use of the fibula free flap for mandibular reconstruction after ameloblastoma resection provides excellent flexibility, enabling effective bone integration of dental implants. Full article

Background: Autism spectrum disorder (ASD) represents a neurobiological disorder with a high prevalence in the children’s population. The aim of the present review was to assess the current evidence on the use of salivary biomarkers for the early diagnosis of ASD. Materials and methods: A search was conducted on the electronic databases PUBMED/Medline, Google Scholar and Scopus for the retrieval of articles concerning the study topic. Results: A total of 22 studies have been included in the present review considering 21 articles identified from databases and 1 article included using a manual search. A wide range of biomarkers have been proposed for early detection of ASD diseases including nonspecific inflammation markers like interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor α (TNFα), oxidative stress markers like superoxide dismutase and glutathione peroxidase, hormones such as cortisol and oxytocin, various microRNAs including miR-21, miR-132 and miR-137, and exosomes. The techniques used for biomarke detection may vary according to molecule type and concentration. Conclusions: salivary biomarkers could represent a potential useful tool for the primary detection of several systemic diseases including ASD, taking advantage of non-invasiveness and cost-effective capability compared to other biofluid-based diagnostic techniques. Full article

Background: Obstructive sleep apnea (OSA) is a prevalent disorder in both pediatric and adult populations, characterized by substantial morbidity encompassing cardiovascular, neurocognitive, and metabolic impairments. Management strategies vary by age group and underlying etiology, with orthodontic and non-orthodontic interventions playing key roles. This narrative review synthesizes the current evidence on orthodontic and non-orthodontic therapies for OSA in pediatric and adult populations, emphasizing individualized, multidisciplinary care approaches and highlighting future research directions. Methods: A narrative review was conducted using PubMed, Scopus, and Google Scholar to identify studies on diagnosis and management of OSA in children and adults from 2000 to 2025. Results: In pediatric patients, treatments such as rapid maxillary expansion (RME), mandibular advancement devices (MADs), and adenotonsillectomy have shown promising outcomes in improving airway dimensions and reducing apnea–hypopnea index (AHI). For adults, comprehensive management includes positive airway pressure (PAP) therapy, oral appliances, maxillomandibular advancement (MMA) surgery, and emerging modalities such as hypoglossal nerve stimulation. Special attention is given to long-term treatment outcomes, adherence challenges, and multidisciplinary approaches. Conclusions: The findings highlight the need for individualized therapy based on anatomical, functional, and compliance-related factors. As the understanding of OSA pathophysiology evolves, orthodontic and adjunctive therapies continue to expand their role in achieving durable and patient-centered outcomes in sleep apnea management. Full article

Objectives: Torus mandibularis (TM) is a benign bony exostosis on the lingual surface of the mandible, typically developing from the third decade of life with slow progression; its etiology remains unclear. As TM excision causes no functional or aesthetic disadvantages, its use as autologous bone graft material (e.g., for pre-implant or sinus lift augmentation) has been suggested. In this study, we investigate the prevalence and expression of TM in a southern German population with regard to age and gender. Additionally, we examine whether TM undergoes dynamic changes over time, with the hypothesis that TM may show temporal growth. Material and Methods: A retrospective analysis of CBCT scans from 210 randomly selected patients (105 males, 105 females) was performed. Patients were divided into three age groups (≤40, 41–60, ≥61 years; 70 per group), and TM was measured using OsiriX MD. For the longitudinal study, 146 CBCTs from 73 patients were compared over intervals of 2–9 years. Surface changes were assessed via 3D overlay using GOM Inspect. Results: TM was found in 30.5% of patients, and its prevalence was significantly higher in males (38%) than females (23%), with no age-related differences identified. Most TMs measured <2 mm (n = 51); only five exceeded this size. No dynamic growth was observed over time. Conclusion and Clinical Implications: TM is a common anatomical variant, more frequently detected through 3D imaging than clinical examination. In most cases, size remains minimal (<2 mm), limiting its clinical use as augmentation material in rare individual cases. Full article

Background: Stable post-surgical wound healing surrounding teeth and dental implants is essential for achieving excellent clinical outcomes, both during the initial phases of treatment and over the long term. Objectives: This work follows the new emerging trend of case-based literature reviews. The aim of this review includes providing clinical findings from case series that demonstrate the efficacy of using blue^®m oxygen treatment to promote post-surgical wound healing in patients that underwent periodontal and dental implant surgeries. In addition, a systematic review of the literature aimed to answer the focused research question: “In periodontal and implant surgeries, what are the aftercare protocols used to maintain optimal wound healing?” Case Presentation: One clinical case report involved the presentation of complex periodontal surgery. The other two cases focused on advanced implant surgeries. All patients were treated post-surgically with the local application of an oxygen-based therapy (blue^®m) gel. This therapy was further emphasized during the wound-healing phase by instructing patients to maintain thorough dental hygiene using toothpaste and mouthwash containing a similar oxygen-release formulation (blue^®m). Patients achieved satisfactory treatment outcomes. Systematic Review: PubMed and EMBASE were used in order to search for relevant studies in the scientific literature published up until June 2025. Only human clinical studies that used a specific protocol in regard to aftercare wound healing after periodontal or dental implant surgeries were included. As a result, 27 clinical studies were included. The outcome data were categorized and summarized. Conclusions: The use of local oxygen-based therapy showed a positive effect as a conventionally used aftercare modality in maintaining optimal post-surgical wound healing, following periodontal and implant surgeries. Further clinical studies are needed. Full article

Background/Objectives: Emerging evidence links diabetes to increased cancer risk. This study aimed to assess the association between diabetes mellitus (DM)(type 1, type 2, or gestational) and the development of head and neck cancer. Methods: An umbrella review was conducted using systematic searches in Cochrane, EBSCO, Wiley, ScienceDirect, and PubMed (January 2000–January 2024), registered in PROSPERO (CRD42024512151). Included were systematic reviews (SRs) and meta-analyses (MAs) of observational studies. Article selection followed the PRISMA guidelines; the quality and risk of bias of the selected studies were assessed with the Joanna Briggs Institute Checklist. The GROOVE tool was used to identify double counting. Two independent reviewers screened studies, with a third resolving disagreements. Results: Seven SRs were included. While DM has been widely examined in cancer research, few studies specifically targeted head and neck cancers. Of the 20 associations between various cancer sites and diabetes types, 9 (45%) showed a statistically significant positive correlation. The strongest evidence was for overall cancer risk (RR = 1.22, 95% CI: 1.16–1.29, p < 0.001). Oral cancer showed elevated risks (RRR = 1.13, p = 0.009; OR = 1.32, p < 0.001; HR = 1.73, p < 0.05; RR = 1.28, p < 0.05). Increased risks were also observed for oropharyngeal (RR = 1.18; HR = 1.53), head and neck (HR = 1.47), and nasopharyngeal cancer (OR = 1.40), all p < 0.05. Heterogeneity was low in two reviews, unreported in one, and high in four. Five SRs reported associated risk factors. Conclusions: While some associations between DM and cancer appear significant, evidence remains limited and inconsistent, particularly for oral cancer. Further standardized, high-quality research is needed to clarify the link across head and neck cancer subtypes. Full article