Has the 8th American joint committee on cancer TNM staging improved prognostic performance in oral cancer? A systematic review / ¿Ha mejorado la estadificación TNM del octavo comité conjunto estadounidense sobre cáncer? ¿Rendimiento pronóstico en el cáncer oral? Una revisión sistemática

Background: The 8th edition of the American Joint Committee on Cancer (AJCC) classification has introduced two new parameters: depth of invasion (DOI) and extranodal extension (ENE). The aim of this systematic review was to determine whether this 8th edition referred to oral squamous cell carcinoma (OSCC) offers performance superior to that of the 7th edition in relation to overall survival (OS) and disease-specific survival (DSS). Material and Methods: The review was carried out following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The PubMed (MEDLINE), Scopus and Cochrane Library databases were searched covering the period up until April 7th, 2022.Results: Thirteen retrospective cohort studies were finally included. The introduction of DOI and ENE in the 8th edition of the AJCC classification resulted in improved prognostic performance of the classification. Conclusions: Patients with OSCC can be better classified in relation to OS and DSS, while maintaining the simplicity and ease of use of the classification. This allows more appropriate treatment protocols to be applied and affords a better estimation of the prognosis of each patient.(AU)

Evaluation of the efficacy of hydroxyl radical (OH) release for disinfection of the air and surfaces in the dental clinic: an in vitro study / Evaluación de la eficacia de la liberación de radicales hidroxilo (OH) para la desinfección del aire y superficies en la clínica dental: un estudio in vitro

Background: Concerning about the quality of room air has increased exponentially. Specially in dental clinicswhere diary practice is characterized by the important generation of aerosols.Material and Methods: An in vitro model was used in which samples were collected from the surfaces and roomair of a dental clinic before and after the use of an OH˙ radical generator.Results: A total of 1260 samples were collected for bacteriological analysis and 14 samples for the detection ofSARS-CoV-2. Following OH˙ treatment, the tested surface samples showed a decrease in the number of colonyforming units (CFUs) of 76.9% in TSA culture medium. The circulating room air samples in turn showed adecrease in CFUs of 66.7% in Sabouraud medium and 71.4% in Mannitol agar medium. No presence of SARS-CoV-2 was observed on the surface of the face shield.Conclusions: The disinfectant technology based on the use of hydroxyl radicals (OH˙) is effective in reducing thepresence of moulds and yeasts and Staphylococcus in the air, and in reducing total aerobic bacteria on the testedsurfaces.(AU)

Disinfection of the air and surfaces in the dental clinic using hydroxyl radical (OH-) based technology: A systematic review.

Background: A systematic review was carried out to compare the disinfectant capacity of hydroxyl radicals (OH-) versus other products commonly used for disinfecting the air and surfaces. Material and Methods: A literature search was made of the Cochrane Library, PubMed (MEDLINE) and Scopus databases. "In vitro" studies evaluating disinfection methods applicable to several surfaces and room air were included in the search. The search was carried out in April 2022, with no restrictions in terms of language or publication date. Results: Of the 308 articles identified from the initial search, 8 were included for the quantitative analysis. All publications corresponded to experimental "in vitro" studies. Seven of them evaluated biocidal action against bacteria, and only two assessed activity against viral loads. The generation of contaminants secondary to application of the disinfectants was only analyzed in one of the studies, with the conclusion that the production of peroxyl radicals (RO2) derived from the oxidation of volatile organic compounds (VOCs) is greater when chemical surface disinfectants are used versus air disinfection systems. Conclusions: The disinfection capacities of the currently available methods are similar, and none of them are able to replace the use of additional physical protection measures. Key words:Disinfection methods, hydroxyl radical, environment, surfaces, dentistry.

Effect of Implantoplasty on Roughness, Fatigue and Corrosion Behavior of Narrow Diameter Dental Implants.

Implantoplasty (IP) is used in dental implants with peri-implantitis and aims to remove threads and polish rough surfaces in order to prevent bacterial colonization. As a result of this procedure, implant strength might be compromised. We tested 20 tapered screw-shaped Ti6Al4V dental implants with a simulated bone loss of 50%. Ten implants underwent IP and 10 served as controls. Surface topography (Sa, Sz, Ssk, and Sdr) was analyzed with a confocal optical microscope. Subsequently, a minimum of four series of cyclic loads were applied with a servo-hydraulic mechanical testing machine (5 × 106 cycles at 15 Hz, between a maximal nominal value-starting at 529 N in the IP group and 735 N in the control group-and 10% of that force). We recorded the number of cycles until failure and the type of failure. Implant failure was analyzed by visual inspection and scanning electron microscopy. Open circuit potential and potenctiodynamic tests were carried out with high precision potentiostat using Hank's solution at 37 °C to evaluate the effect of the implantoplasty on the corrosion resistance. Implantoplasty significantly reduced the surface topography values (median) and interquartile range (IQR); Sa from 1.76 (IQR = 0.11) to 0.49 (IQR = 0.16), Sz from 20.98 (IQR = 8.14) to 8.19 (IQR = 4.16), Ssk from 0.01 (IQR = 0.34) to -0.74 (IQR = 0.53) and Sdr from 18.20 (IQR = 2.26) to 2.67 (IQR = 0.87). The fatigue limits of the control and implantoplasty groups were 551 N and 529 N, respectively. The scanning electron micrographs showed fatigue striations indicating fatigue failure. Besides, the fractographic analysis revealed a typical brittle intergranular fracture mechanism. The infinite life range of the dental implants evaluated was largely above the threshold of usual chewing forces. Implantoplasty seems to render a fairly smooth surface and has a limited impact on fatigue resistance. In addition, implantoplasty produces a decrease in the corrosion resistance of the implant. Corrosion current density from 0.019 µA/cm2 for as-received to 0.069 µA/cm2 in the interface smooth-roughened dental implant. These places between the machining and the rough area of the implant are the most susceptible, with the appearance of pitting.

Comparison of external, internal flat-to-flat, and conical implant abutment connections for implant-supported prostheses: A systematic review and network meta-analysis of randomized clinical trials.

STATEMENT OF PROBLEM: The implant abutment connection interface has been considered one of the major factors affecting the outcome of implant therapy. However, drawbacks of traditional meta-analyses are the inability to compare more than 2 treatments at a time, which complicates the decision-making process for dental clinicians, and the lack of a network meta-analysis. PURPOSE: The purpose of this network meta-analysis was to assess whether the implant abutment connection influences the outcome of implant-supported prostheses. MATERIAL AND METHODS: An electronic search was undertaken to identify all randomized clinical trials comparing the effect of at least 2 different implant abutment connection designs published from 2009 up to May 2020. Outcome variables were implant survival rate, peri-implant marginal bone loss, and biologic and prosthetic complication rates at 12 months after prosthetic loading. Relevant information was extracted, and quality and risk of bias assessed. Pairwise meta-analyses and network meta-analyses based on a multivariate random-effects meta-regression were performed to assess the comparisons (α=.05 for all analyses). RESULTS: For peri-implant marginal bone loss and prosthetic complications, conical interfaces were determined to be the most effective, with significant differences when compared with external hexagonal connections (P=.011 and P=.038, respectively). No significant differences were found among the implant abutment connections in terms of survival and biologic complications (P>.05 in all direct, indirect, and mixed comparisons). CONCLUSIONS: After 1 year of loading, conical connections showed lower marginal bone loss and fewer prosthetic complications than external hexagonal connections. However, the implant abutment connection design had no influence on the implant survival and biologic complication rates.

Ion release and local effects of titanium metal particles from dental implants: An experimental study in rats.

BACKGROUND: The objective of this study was to evaluate the accumulation of ions in blood and organs caused by titanium (Ti) metal particles in a mandibular defect in rats, together with a description of the local reaction of oral tissues to this Ti alloy debris. METHODS: Twenty Sprague-Dawley rats were randomly distributed into three groups: an experimental group with a mandibular bone defect filled with metallic debris obtained by implantoplasty; a positive control group; and a negative control group. Thirty days after surgery, the rats were euthanized and perilesional tissue surrounding the mandibular defect was removed, together with the lungs, spleen, liver, and brain. Two blood samples were collected: immediately before surgery and before euthanasia. The perilesional tissue was histologically analyzed using hematoxylin-eosin staining, and Ti, aluminum, and vanadium ion concentrations in blood and organs were measured by TQ-ICP-MS. Descriptive and bivariate analyses of the data were performed. RESULTS: All rats with implanted metal debris showed metal particles and a bone fracture callus on the osseous defect. The metal particles were surrounded by a foreign body reaction characterized by the presence of histiocytes and multinucleated giant cells (MNGCs). The experimental group had a significant higher concentration of Ti ions in all studied organs except lung tissue (p < 0.05). In addition, there were more V ions in the brain in the experimental group (p = 0.008). CONCLUSIONS: Although further studies are required to confirm the clinical relevance of these results, Ti metal particles in the jaw might increase the concentration of metal ions in vital organs and induce a foreign body reaction.

Incidence of mandibular osteoradionecrosis (MORN) after intensity modulated radiotherapy (IMRT) versus 3D conformal radiotherapy (3D-CRT): A systematic review

Background: Analyze the incidence of MORN after head and neck radiotherapy by two novel irradiation techniques, 3DCRT and IMRT and compare the success rates of distinct authors.Material and methods: An electronic search in Pubmed (MEDLINE), Ovid, Google Scholar and Cochrane Library (Wiley), databases was conducted with the key words "Radiotherapy, Conformal"[Mesh] OR "Radiotherapy, Intensity-Modulated"[Mesh]) AND "Osteoradionecrosis"[Mesh] for all databases. The inclusion criteria randomized controlled trials (RCT), as well as prospective and retrospective cohort studies published in English; MORN patients treated with 3D-CRT y IMRT. Results: 27 articles were selected from 194 initially found. 14 articles out of 27 were excluded and finally included 8 publications were included in the systematic review that were ranked according to their level of scientific evidence using the SORT criteria. Conclusions: When both RT techniques were compared; IMRT revealed a lower risk incidence of MORN development and enhanced dose constraint than 3D-CRT (less than 10%), this improvement could translate into less complications post RT treatment. (AU)

Evaluation of the inflammatory and osteogenic response induced by titanium particles released during implantoplasty of dental implants.

Implantoplasty is a mechanical decontamination technique that consists of removing the threads and polishing and smoothing the dental implant surface. During implantoplasty there is a large release of titanium metal particles that might provoke a proinflammatory response and reduce the viability of osteogenic cells. We analyze the inflammatory and osteogenic response induced by Ti6Al4V particles released during implantoplasty and by as-received commercially pure Ti particles. Macrophages stimulated with metal particles obtained by implantoplasty and with as-received Ti particles showed an increased proinflammatory expression of TNF-α and a decreased expression of TGF-ß and CD206. Regarding cytokine release, there was an increase in IL-1ß, while IL-10 decreased. The osteogenic response of Ti6Al4V extracts showed a significant decrease in Runx2 and OC expression compared to the controls and commercially pure Ti extracts. There were no relevant changes in ALP activity. Thus, implantoplasty releases metal particles that seems to induce a pro-inflammatory response and reduce the expression of osteogenic markers.

Color doppler ultrasound for the assessment of palatal fibromucosa thickness and the trajectory of the greater palatine artery: A pilot study.

Background: The primary objective of this study was to determine the position and course of the greater palatine artery using color doppler ultrasound. The secondary objective was to determine the thickness of the palatine fibromucosa. Material and Methods: A pilot case series study was performed in a private clinic during February 2020. The scans were performed with a Mindray® M9 ultrasound machine (Mindray North America, NJ, USA) coupled to an L16-4Hs® hockey-type angled probe. For each participant, the arterial path and thickness of the palatal fibromucosa were determined at 5 different points. Results: A total of 6 volunteers (3 males and 3 females) with a mean age of 39.2 (±16) years were included. While the thickness of the fibromucosa decreased along the anterior area, the distance from the cementoenamel junction to the position of the artery was generally maintained up to the canine position, where it was found to be closed to teeth. Conclusions: Color doppler ultrasound allows accurate localization of the artery as well as measurement of the thickness of the palatine fibromucosa. It would help to select the best area for graft harvesting in order to avoid bleeding complications due to vascular sectioning. Key words:Hard palate, doppler ultrasonography, diagnosis, connective tissue graft.

Odontogenic maxillary sinusitis and fungus ball development secondary to a dental root retained for more than 25 years. A case report.

The displacement of a dental root fragment into the maxillary sinus is a serious complication of tooth extraction that can give rise to maxillary sinusitis. The condition can become chronic if the intrasinusal foreign body is not promptly removed, and Aspergillus fumigatus superinfection may ultimately result, forming a fungus ball. The present study describes the case of a 50-year-old man with fungal rhinosinusitis caused by the accidental displacement of a dental root over 25 years ago. The prolonged and atypical course of the disorder produced long diagnostic and therapeutic controversy, and justifies the publication of this clinical case, which affords useful information for routine clinical practice. Key words:Odontogenic maxillary sinusitis, fungus ball, tooth displacement, aspergillosis, diagnostic and therapeutic controversy.

Previous dry socket as a risk factor for alveolar osteitis: A nested case-control study in primary healthcare services.

Background: Dry socket is one of the most common complications following tooth extraction, though no studies have been made on its main risk factors in the primary healthcare services of Barcelona (Spain). Objectives: To analyze the influence of different factors upon the appearance of dry socket in patients attended in the primary care setting, and to determine the possible presence of risk factors in patients who have suffered a previous episode of dry socket. Material and Methods: During 24 months, questionnaires were filled with data on the patients seen in different public primary healthcare services in the area of Barcelona (Spain). A case-control study was conducted to identify the main risk factors for developing complications in the form of dry socket. Results: A mandibular location of the extracted tooth, poor oral hygiene, difficult extraction, and previous dry socket increased the risk of developing this complication. In patients with dry socket in the past, the risk of developing the same complication again, adjusted for difficulty of extraction, was seen to increase 11.45-fold (OR: 11.45; 95%CI: 1.06 to 123.74; p = 0.045). Conclusions: The risk factors for dry socket are a mandibular location of the extracted tooth, poor oral hygiene, difficult extraction, and particularly a history of dry socket in the past. The identification of these factors the prevention of dry socket in each patient could be improved. Key words:Dry socket, risk factors, extraction, complications.

Prevalence of Periodontitis among Patients Diagnosed with Marfan Syndrome: A Cross-Sectional Study Comparing Samples of Healthy Patients.

Periodontitis is an inflammatory condition caused by a bacterial plaque and characterized by progressive destruction of the tooth-supporting apparatus. Patients with Marfan syndrome (MFS) exhibit a connective tissue disorder, which can also affect oral soft and hard tissue. Thus, the aims of this cross-sectional study were to assess the association between periodontitis and MFS and secondly, to compare periodontal parameters and prevalence of disease with a control group (CG) without MFS. 152 patients (MFS = 76, CG = 76) were recruited to evaluate the following periodontal parameters: probing depth, gingival margin, clinical attachment level, plaque index, and bleeding on probing. The 2017 World Workshop guideline was followed for the diagnosis of the periodontal status. A multivariate analysis was performed using a multinomial logistic regression adjusted for age, gender, and smoking. The level of significance required was p < 0.05. Patients with MFS did not show a higher prevalence of periodontitis compared to the CG. However, patients with MFS did have higher values in probing depth, gingival recession, clinical attachment level, and plaque index compared to the CG patients (p < 0.05). In conclusion, although similar prevalence of periodontitis was found among the studied groups, MFS patients showed worse periodontal parameters.

Efficacy of the use of chondroitin sulphate and glucosamine for the treatment of temporomandibular joint dysfunction: A systematic review and meta-analysis.

OBJECTIVE: To evaluate the efficacy of chondroitin sulfate (CS) and glucosamine (GS), the most relevant drugs of "Symptomatic Slow Acting Drug for Osteoarthritis" (SYSADOA), in the functional and symptomatic improvement of temporomandibular dysfunction. Although, controversy exists regarding their benefit. METHODS: An electronic search was conducted to retrieve randomized controlled clinical trials (RCTs). The risk of bias assessment was evaluated using the Cochrane Collaboration's tool. Data were meta-analyzed with a random effect model whenever possible. RESULTS: Three RCTs were included. Qualitative results showed a decrease in pain, joint noise, and inflammatory biomarkers in synovial fluid and an improvement in maximum mouth opening without significant adverse effects. Meta-analysis showed a significant increase in maximum mouth opening with the use of CS-GS (p = 0.19). No statistically significant differences were found in pain reduction compared to tramadol. CONCLUSION: CS-GS is effective and safe in the symptomatic and functional improvement of patients with TMD.

Clinical effect of vitamin C supplementation on bone healing: A systematic review

Background: The aim of the present systematic review was to evaluate the clinical effect of vitamin C on bone healing after bone fracture or bone reconstruction procedures. Material and Methods: In October 2020, Cochrane Library, Scopus and PubMed-Medline databases were searched without restrictions to identify animal and human studies that fulfilled the eligibility criteria. Outcome measures were bone healing time, bone gain (mm), bone density and adverse events. The risk of bias assessment of the selected studies was evaluated by means of Cochrane Collaboration’s Tool for randomized clinical trials, while randomized clinical animal trials were assessed according to SYRCLE’s tool. Additionally, quality of reporting animal studies were assessed according to ARRIVE guidelines. Results: Out of the 248 articles that yielded the initial search, 11 papers about the effect of ascorbic acid on bone healing were selected. In most of the animal studies, vitamin C seemed to accelerate bone formation owing to an enhanced osteoblastic proliferation and differentiation and its antioxidant function when pro-oxidant substances were added. It was not possible to observe this phenomenon in human studies. Conclusions: Although additional well-performed animal and human studies are required, vitamin C seems to accelerate bone regeneration without adverse events. However, it is not possible to recommend a specific dose or route of administration of vitamin C to improve the bone healing process in humans as there was great heterogeneity among the included studies.(AU)

Prevalence of intraoperative and postoperative iatrogenic mandibular fractures after lower third molar extraction: A systematic review.

BACKGROUND: The surgical extraction of the lower third molars is one of the most common procedures in oral surgery, and this surgical operation can cause intra- and postoperative complications such as pain, trismus, bleeding, infection, oedema, inferior alveolar nerve injuries, displacement of teeth to neighbouring spaces and mandibular fractures. The aim of this systematic review is to report the prevalence of mandibular fractures that occur intra- and postoperatively in patients who have undergone surgical removal of the lower third molar. MATERIAL AND METHODS: An electronic database search for articles published in Cochrane, PubMed (MEDLINE) and Scopus was conducted using the key words "Molar, Third"; "Mandibular Fractures"; "Molar Third, Removal"; "Molar Third, Complications"; "Dental Extractions, Complications"; "Mandibular Fractures, Third molar removal". The inclusion criteria were articles including at least 10 patients and were published in English in the last 10 years. The exclusion criteria were nonhuman studies and case reports. RESULTS: Postoperative mandibular fractures after 3MI occur more frequently in male patients between the ages of 40 and 60 and are caused by premature chewing force. The parameters that most frequently characterise mandibular fractures at the mandibular angle are deeply impacted lower third molars, Class II and III, B and C, according to the Pell & Gregory classification system, mesioangular according to the Winter's classification, and are located on the left mandibular side.. CONCLUSIONS: Mandibular fractures can be predicted with adequate preoperative planning for each case and identify the related risk factors for this complication. Key words:Molar, Third; Mandibular Fractures; Molar Third, Removal; Molar Third, Complications; Dental Extractions, Complications; Mandibular Fractures, Third molar removal.

Third molar surgical difficulty scales: systematic review and preoperative assessment form

Background: The main objective of this systematic review was to collect the pre-existing scales for assessing the difficulty of third molar extraction. The secondary objective was to design a proposal for a preoperative evaluation protocol for the difficulty of third molar extraction. Material and Methods: Two independent researchers conducted an electronic search in Pubmed (MEDLINE), Cochrane, and Scopus databases during March 2021. Included studies evaluated the prediction of the difficulty of surgical removal of impacted upper or lower third molars using new indices/scales or pre-existing scales with or without modifications. Articles referring to coronectomies or assessing pre-surgical difficulty using other tools were excluded. Neither language nor publication date restrictions were applied. Results: Out of 242 articles, 13 prospective cohort studies were finally selected. Seven developed new indices/scales, and 6 assessed the predictive ability of some pre-existing scales. Most of the indices/scales contained radiological variables and few added any patient-related variables. We proposed a preoperative assessment protocol of the difficulty of third molar extraction to facilitate treatment planning and/or considerate referral in cases of high difficulty. This proposal used patient-related, radiological and surgical variables. Conclusions: Using a preoperative protocol to evaluate the surgical difficulty, including different patient-specific, radiological and surgical variables, could facilitate treatment planning, help clinicians prevent complications and assess the possibility of referral.(AU)

Intraarticular injections of platelet rich plasma and plasma rich in growth factors with arthrocenthesis or arthroscopy in the treatment of temporomandibular joint disorders: A systematic review.

Intra-articular platelet rich plasma injections [PRP] or platelet rich growth factors [PRGF] injections have been used as therapeutic treatment options for patients with temporomandibular joint disorder [TMD] in recent years. The purpose of this paper is to evaluate the level of the available scientific evidence in the current literature on the benefits of applying PRP or PRGF injections to patients with TMD simultaneously or after arthrocentesis or arthroscopy to reduce post-operative pain and improve temporomandibular joint function. This systematic review was conducted according to PRISMA criteria and an electronic database search was carried out in the PubMed, Scopus and Cochrane databases during May 2021. The patients in the study group were injected with intra-articular PRP or PRGF simultaneously or after arthrocentesis or arthroscopy while the patients in the control group had arthrocentesis or arthroscopy without an intra-articular injection or received an injection of hyaluronic acid or Ringer's lactate solution. Eight randomised controlled clinical trials were selected. The PRP and PRGF intra-articular injections demonstrated significant differences in terms of pain reduction in three studies and improved mandibular function in two. The treatment with PRP or PRGF intra-articular injections demonstrated slightly better clinical results but of little significance in comparison with the control group. Evidence of their effectiveness is crucial to establish them as non-invasive treatments and as an affordable option for treating some types of TMDs. In accordance with Evidence-based dentistry principles, this review has been assigned a C recommendation.

Clinical and Histological Outcomes of Maxillary Sinus Floor Augmentation With Synthetic Bone Substitutes for Dental Implant Treatment: A Meta-Analysis.

The main objective of this study was to compare the clinical and histological results of synthetic bone substitutes used in maxillary sinus floor augmentation. A systematic review and meta-analysis was performed by searching the PubMed/MEDLINE, Scopus, and Cochrane databases for studies of the success of endosseous dental implant, implant failure, peri-implant marginal bone loss, newly formed bone, and residual bone graft material. After the search, 10 randomized clinical trials were included, with 4 studies ranging from low to unclear risk of bias were used for meta-analysis, comparing biphasic calcium phosphate (BCP) and deproteinized bovine bone (DBB). A greater amount of residual graft material (mean difference [MD]: -4.80 mm; 95% CI: -9.35 to -0.26; P = .040) was found in the DBB group. No other statistically significant differences were found between BCP and DBB for the remaining outcomes. Our results suggested that BCP can be considered a suitable alternative to DBB in maxillary sinus floor augmentation due to its clinical and histological results.

Retrospective Cohort Study on the Influence of Bone Remodeling on Marginal Bone Loss and Peri-implantitis Around Immediately Loaded Implants Supporting Complete-Arch Restorations.

PURPOSE: The main objective of this study was to assess the influence of bone remodeling on late marginal bone loss in immediately loaded, implant-supported, complete-arch restorations and, secondarily, to determine its relationship to peri-implant disease occurrence using a multilevel analysis. MATERIALS AND METHODS: A retrospective cohort study of patients treated consecutively in a private clinic with immediately loaded full-arch restorations with at least 12 months of follow-up was conducted. Bone remodeling and marginal bone loss were determined through measurements made on panoramic radiographs by two calibrated examiners. Peri-implant health status was diagnosed in a visit for peri-implant maintenance. Descriptive, bivariate, and multilevel analyses were performed with Stata/IC 15.1 software (StataCorp). RESULTS: A total of 30 patients (11 men and 19 women, mean age: 63.3 ± 10.4 years), with a mean follow-up of 37.7 ± 19.6 months were included. Forty arches (20 maxillary and 20 mandibular) received 207 implants. Bone remodeling had an inversely proportional effect on marginal bone loss (P =.005) but was not related to peri-implantitis (P =.103; hazard rate [HR] = 2.1). CONCLUSION: Taking into account the limitations of this study, bone remodeling around immediately loaded dental implants supporting complete-arch restorations does not appear to increase marginal bone loss or peri-implantitis.

Critical assessment of the latest classification of jaw cysts proposed by the World Health Organization (2017).

BACKGROUND: The fourth edition of the World Health Organization Classification of Head and Neck Tumors was published in January 2017, and includes a classification of odontogenic tumors and odontogenic cysts. The present review assesses the changes made in this new classification in relation to odontogenic and non-odontogenic jaw cysts. MATERIAL AND METHODS: An electronic search was conducted in the Cochrane Library, PubMed-MEDLINE and Scopus databases using the search terms: "odontogenic cyst" "WHO classification" "update". Studies written in English and published between January 2005 and April 2020 with a high level of scientific evidence were included, while studies not published in English, epidemiological studies, and studies with a low level of scientific evidence were excluded. RESULTS: The initial search identified 311 articles, and after the deletion of duplicates, 7 studies were selected for full-text assessment. After excluding two studies that failed to provide relevant information and had a low level of scientific evidence, 5 articles were finally included and stratified according to their level of scientific evidence based on the SORT (Strength of Recommendation Taxonomy) criteria. CONCLUSIONS: The incorporation of odontogenic and non-odontogenic cysts to the head and neck tumors classification underscores the recognition of the WHO of these important disorders of the jaws. Based on the current evidence, there is controversy as to whether odontogenic keratocysts should be regarded as cystic lesions or as neoplasms, though there is no such controversy in relation to calcifying odontogenic cysts. On the other hand, orthokeratinized odontogenic cysts have been included in the classification as a single entity differentiated from odontogenic keratocysts, while residual cysts have been removed from the classification. Key words:Odontogenic cyst, WHO classification, pseudocyst.