Prevalence of impacted third molars: a radiographic study among a North African population.

INTRODUCTION: Third molars are the most commonly concerned teeth with the impaction. Impacted third molar (ITM) can be associated to various clinical pathologies Aim: To determine the prevalence of ITM, its pattern and associated affections in Tunisian patients. METHODS: The study reviewed panoramic radiographs of patients consulting the Fattouma Bourguiba University Hospital, Monastir (Tunisia). Orthopantomograms were analyzed to define the prevalence of ITM; its angulation, depth and relation with the anterior border of mandibular ramus. Associated pathologies were also assessed. RESULTS: Seven hundred and thirty patients were included (286 men and 444 women). The age ranged from 19 to 89 years. Half of the patients (50.3%) showed at least one ITM. The total number of ITM was 881 with a statistical difference between arches (respectively 34.3% and 65.7% in the maxilla and in the mandible). The most common number of ITM was two (35.4%). Level C of impaction was observed more frequently in the maxilla and level A in the mandible. The most common angulation was the vertical one for both arches. Seventy six percent of ITM were presented with class II in relation with the anterior border of mandibular ramus. There was no significant difference in the frequency of impaction between gender and sides. The number of ITM associated with pathological conditions was 199 (22.6%). The most frequently observed pathology was the distal caries on the second molars (11.7%) followed by the caries of the third molars (5.2%). CONCLUSION: The prevalence of ITM among Tunisian patients was high.

Age estimation through the development of third molars in a case of multiple dismemberment / Estimación de la edad mediante el desarrollo de terceros molares en un caso de desmembramiento múltiple

El crimen organizado se ha convertido en un flagelo a nivel internacional conformado por grupos al margen de la ley que realizan todo tipo de actividades que involucran desde tráfico de personas, secuestros, extorsiones, narcotráfico y muchos otros delitos. Producto de este fenómeno, la desaparición y ejecución de personas es cada día más frecuente, en muchos casos los cuerpos son quemados o desmembrados para impedir o hacer más difícil la identificación. La odontología forense se ha convertido en una disciplina transcendental en la identificación de cadáveres y restos óseos, además de contar con múltiples métodos para estimar la edad aproximada de una persona. Se presenta el caso de un descuartizamiento múltiple de tres individuos masculinos donde era indispensable identificar si alguno correspondía a una persona menor de 18 años.

Organized crime has become an international scourge made up of outlaw groups that carry out all kinds of activities ranging from human trafficking, kidnapping, extortion, drug trafficking and many more. As a result of this phenomenon, the disappearance and execution of people is becoming more frequent every day, in many cases the bodies are burned or dismembered to prevent or make identification more difficult. Forensic odontology has become a transcendental discipline in the identification of corpses and skeletal remains, in addition to having multiple methods to estimate the approximate age of a person. The case of a multiple dismemberment of three male individuals is presented, where it was essential to identify a person under 18 years of age.

An Observational Study on Cystic Alterations in Normal Dental Follicles Associated with Impacted Lower Third Molar for Early Intervention.

AIM: To evaluate the cystic changes in the radiographically normal dental follicle associated with impacted mandibular third molar. MATERIALS AND METHODS: This study was conducted on 80 patients. Samples were selected using a convenient sampling technique from the patients who had impacted mandibular third molars in Pell and Gregory's positions B and C, with follicular space less than 2.5 mm in diameter. After surgical removal of an impacted tooth, the dental follicle was sent for histopathologic evaluation. RESULTS: Pathologic alterations were found in 19% of cases out of 80 samples. Odontogenic keratocystic and dentigerous cystic changes were found in 7% of cases. A statistically significant cystic alteration was found in female patients and distoangular impacted teeth. CONCLUSION: This study shows a significant cystic alteration in the radiologically normal dental follicles. Clinical and radiographic features alone may not be a reliable indicator of the absence of pathology. Early intervention of impacted teeth will help to reduce morbidity due to the development of pathology. CLINICAL SIGNIFICANCE: This study will help educate patients on the risks of retaining impacted teeth, based on scientific facts, in order to minimize the risks and to assess the correlation of pathologic alterations with the depth of impaction and angular position of the impacted tooth.

[General ideas about the stages, classifications, pathological conditions during the lower third molars eruption in humans. Literature review. Part 2]. / Obshchie predstavleniya o stadiyakh, klassifikatsiyakh, patologicheskikh sostoyaniyakh pri prorezyvanii nizhnikh tret'ikh molyarov u cheloveka. Obzor literatury. Chast' 2.

The article is a review of literature data on the stages, classifications, pathological conditions during the eruption of the lower third molars in humans. The authors analyzed the established knowledge about clinical and morphological changes at various stages of eruption of the lower third molars, studied new data describing the pathogenetic, histological and biochemical features of their development, packaging, movement to the occlusal plane. The literature review helped to identify a series of current trends that define a number of key hypotheses that summarize the accumulated material and indicate different opinions on the topic under study, which confirms the prospects and relevance of continuing research.

Relationship between Presence of Third Molars and Prevalence of Periodontal Pathology of Adjacent Second Molars: a Systematic Review and Meta-analysis.

OBJECTIVE: To estimate the mean prevalence of periodontal pathology of adjacent second molars (A-M2s) to third molars (M3s) and identify related confounding factors. METHODS: Studies published before August 2020 were systematically searched in the Cochrane Library, EMBASE and MEDLINE databases. We included cross-sectional studies that evaluated the periodontal pathology of A-M2s based on clinical or radiographic examinations at the molar level. Studies employing similar periodontal parameters were pooled. Clinical attachment loss ≥ 3 mm, alveolar bone loss ≥ 3 mm or ≥ 20% root length were defined as early periodontal defects, and at least one site with probing depth ≥ 5 mm was considered as deep periodontal pockets around A-M2s in the data synthesis. RESULTS: Nine studies (14,749 M3s) were ultimately included in the meta-analysis. On average, 19% of A-M2s showed distal early periodontal defects with the presence of M3s (95% confidence interval [95% CI] 9%-35%). Subgroup analyses suggested the prevalence was 32% (95% CI 16%-54%) in the mandible, and the prevalence was higher with nonimpacted M3s (25%, 95% CI 12%-47%) than with impacted M3s (19%, 95% CI 10%-35%). Additionally, the pooled prevalence for deep periodontal pockets around A-M2s was 52% (95% CI 39%-64%). Subgroup analyses suggested the prevalence was higher in the mandible (62%, 95% CI 45%-76%) than in the maxilla (43%, 95% CI 31%-56%), and for nonimpacted M3s the prevalence reached 50% (95% CI 36%-64%). CONCLUSION: The presence of M3s, especially mandibular and nonimpacted M3s, negatively affects the periodontal status of A-M2s.

Investigation of the expression level of long non-coding RNAs in dental follicles of impacted mandibular third molars.

OBJECTIVES: Dental follicle (DF) is made up of mesenchymal cells and fibers surrounding the enamel organ of a developing tooth. It has been shown that cystic and neoplastic lesions can develop from the pericoronal follicles of impacted third molars (ITMs). But the molecular transformation of DF tissues has not yet been uncovered and remains elusive. Accordingly, in the present study, we aimed to investigate the differential expression of lncRNA genes in DF tissues associated with asymptomatic impacted mandibular third molars (IMTMs) that do not show pathological pericoronal radiolucency in radiographic examination. MATERIAL AND METHODS: A total of 30 patients with unilateral mesioangular IMTMs were enrolled for the study. The expressions of lncRNA genes were determined in the DF and healthy gingival tissues obtained from study patients. For the determination of lncRNA expression levels, RNA was isolated from the obtained tissues, converted to cDNA samples, and analyzed by quantitative real-time PCR method. RESULTS: As a result, we found that the gene expression of MEG3 was increased about 10-fold in DF tissues compared to healthy gingival tissues (p < 0.0001). In addition, NORAD expression was found to be upregulated 4.2-fold (p = 0.0002) in DF tissues. Also, expression level of MALAT1 was found to be decreased 1.24-fold (p = 0.584) and TP73-AS1 increased 2.6-fold (p = 0.093) in DF tissues compared to healthy gingival tissues. CONCLUSIONS: Consequently, present findings suggest that differentially expressed lncRNAs in DFs might be associated with the various levels of cellular events including osteogenic differentiation, DNA damage, and the transformation into odontogenic pathology. CLINICAL RELEVANCE: Expression levels of MEG3 and NORAD lncRNA molecules may guide clinicians in the evaluation of asymptomatic ITM dental follicles that cannot be determined radiologically and during extraction of these teeth for prophylactic purposes.

Surgical placement of third molars to replace other teeth: "spare wheels" / Mise en place chirurgicale des dents de sagesse en remplacement d'autres dents : « les roues de secours ¼

Introduction: The prognostic improvement for dental auto-transplants is the result of a better understanding in the physiopathology of the periodontium and also of the refining of the technical operative procedure. This fact allows the use of third molars as donor site for the replacement of absent, or first or second badly decayed molars. Discussion: This possible therapy is a supplement argument for the conservation of third molars and their extraction must be indicated only when the anatomic situation presents a pathological risk. Results: If, in adults, it is possible to compare the advantages and disadvantages with the classical implant or prosthetic techniques, it should however be considered as first choice therapy for adolescents and young adults. Indeed, in these cases, the lower risk of root ankylosis avoids passive intrusion and the osteogenic effect of the desmodontium allows normal alveolar bone formation.

Introduction: L'amélioration du pronostic des autogreffes dentaires, envisageable par une meilleure compréhension de la physiopathologie du parodonte et par un affinement de la technique opératoire qui en résulte, permet d'utiliser à bon compte les dents de sagesse comme site donneur dans le remplacement de molaires absentes ou trop fortement délabrées. Discussion: Cette possibilité thérapeutique est un argument supplémentaire à la conservation des dents de sagesse dont l'extraction ne devrait être indiquée que lorsque la situation anatomique de ces dents présente un risque pathologique. Résultats: Si, chez l'adulte, il est possible d'en discuter les avantages et les inconvénients avec les techniques prothétiques et implantaires classiques, les autogreffes dentaires doivent en revanche être considérées comme la solution de choix chez l'adolescent ou le jeune adulte. En effet, dans ces cas, le risque moindre d'ankylose radiculaire évite l'ingression passive de la dent remplacée et l'action ostéogénique de son desmodonte permet une formation normale de l'os alvéolaire qui l'environne.

Quiste dentígero: correlación de examen imagenológico con diagnóstico de certeza / Dentigerous cyst: corelation between the imaging examination and diagnostic certainty

Se presenta un caso clínico de quiste dentígero, asociado a un tercer molar inferior izquierdo retenido, que concurre a la Cátedra de Diagnóstico por Imáge- nes de la Facultad de Odontología de la Universidad de Buenos Aires. El paciente, de 53 años de edad, es de sexo femenino. Se utiliza la tomografía de haz cónico para diagnosticar presuntivamente dicha patolo- gía. Posteriormente, se realiza biopsia para obtener una muestra y ser enviada para realizar los estudios anatomopatológicos, que corroboran el presuntivo diagnóstico. Basado en lo expuesto, se analiza al quis- te dentígero según ubicación, sexo, edad y maxilar; habiendo realizado una revisión de la literatura (AU)

A clinical case of a dentigerous cyst associated with a retained lower left third molar is presented. The 53-year-old patient is female. Cone beam tomography is used to presumptively diagnose said pathology. Subsequently, a biopsy is performed to obtain a sample and be sent to perform pathological studies that corroborate the presumptive diagnosis. Based on the above, the dentigerous cyst is analyzed according to location, sex, age and maxilla; having carried out a review of the literature (AU)

Pattern of Mandibular Third Molar Impaction in Nonsyndromic 17760 Patients: A Retrospective Study among Saudi Population in Central Region, Saudi Arabia.

The objective of this study was to study the incidence of type of impaction of mandibular third molars based on the classifications of Pell and Gregory and Winter, which included angulation of the tooth and level of the occlusal surface of the third molar with respect to the second molar, respectively, in a sample of Saudi population in central region. In this retrospective study, orthopantomograms (OPGs) of 17760 patients were examined, who were reported by the Dental University Hospital (DUH) at King Saud University, Riyadh, Saudi Arabia, between the years 2016 and 2020. Out of 17760 radiographs, 2187 (12.31%) patients presented with at least one impacted third molar. Out of which, 1337 (7.52%) patients had bilateral impaction and 850 (4.78%) patients had unilateral impaction (p < 0.001). No gender predominance was noted in the impaction status (p > 0.05). In bilateral impaction, 671 were male (50.2%) and 666 were female (49.8%). Among unilateral impaction, 394 (46.4%) were male and 456 (53.6%) were female. Mesioangular angulation was the most common pattern of impaction (65%) followed by vertical angulation in both bilateral and unilateral impactions. Level A impaction was found to be highest in both bilateral and unilateral impactions which are 48.02% and 54.0%, respectively (p < 0.05). Our study highlights mesioangular impaction and level "A" as the most frequently encountered angulation and level of impaction in impacted teeth. This study result provides us useful data regarding the radiographic status of mandibular third molars in the population of Saudi Arabia.

Evaluation of Vitamin D (25OHD), Bone Alkaline Phosphatase (BALP), Serum Calcium, Serum Phosphorus, Ionized Calcium in Patients with Mandibular Third Molar Impaction. An Observational Study.

The aim of this study was to evaluate the levels of vitamin D (25OHD) and other bone biomarkers in patients with third molar impaction (TMI). Thirty males and 30 females with unilateral or bilateral impacted mandibular third molar, and 15 males and 15 females as a control group (CG) were recruited. Rx-OPT was used to evaluate dental position and Pederson index to measure the difficulty of the intervention. Bone biomarkers were measured through blood venous sample in TMI group and CG. Mann-Whitney test, Pearson's correlation coefficient, linear regression model were used to compare the different parameters in the two groups. 25OHD showed lower values in TMI group than in CG (p < 0.05) with values significantly lower in bilateral impaction (p < 0.05). Pearson's coefficient for 25OHD presented a negative correlation with the Pederson index (ρ = -0.75). Bone alkaline phosphatase (BALP) showed significantly lower dosage in TMI group than CG (p = 0.02), Pearson's coefficient for BALP presented a negative correlation with the Pederson index. Serum calcium, serum phosphorus, ionized calcium levels in TMI and CG groups were similar and Mann-Whitney test did not significantly differ between TMI and CG. TMI could be a sign of vitamin D deficiency and of low BALP levels that should be investigated.

Machine learning to predict distal caries in mandibular second molars associated with impacted third molars.

Impacted mandibular third molars (M3M) are associated with the occurrence of distal caries on the adjacent mandibular second molars (DCM2M). In this study, we aimed to develop and validate five machine learning (ML) models designed to predict the occurrence of DCM2Ms due to the proximity with M3Ms and determine the relative importance of predictive variables for DCM2Ms that are important for clinical decision making. A total of 2642 mandibular second molars adjacent to M3Ms were analyzed and DCM2Ms were identified in 322 cases (12.2%). The models were trained using logistic regression, random forest, support vector machine, artificial neural network, and extreme gradient boosting ML methods and were subsequently validated using testing datasets. The performance of the ML models was significantly superior to that of single predictors. The area under the receiver operating characteristic curve of the machine learning models ranged from 0.88 to 0.89. Six features (sex, age, contact point at the cementoenamel junction, angulation of M3Ms, Winter's classification, and Pell and Gregory classification) were identified as relevant predictors. These prediction models could be used to detect patients at a high risk of developing DCM2M and ultimately contribute to caries prevention and treatment decision-making for impacted M3Ms.

Classification of caries in third molars on panoramic radiographs using deep learning.

The objective of this study is to assess the classification accuracy of dental caries on panoramic radiographs using deep-learning algorithms. A convolutional neural network (CNN) was trained on a reference data set consisted of 400 cropped panoramic images in the classification of carious lesions in mandibular and maxillary third molars, based on the CNN MobileNet V2. For this pilot study, the trained MobileNet V2 was applied on a test set consisting of 100 cropped PR(s). The classification accuracy and the area-under-the-curve (AUC) were calculated. The proposed method achieved an accuracy of 0.87, a sensitivity of 0.86, a specificity of 0.88 and an AUC of 0.90 for the classification of carious lesions of third molars on PR(s). A high accuracy was achieved in caries classification in third molars based on the MobileNet V2 algorithm as presented. This is beneficial for the further development of a deep-learning based automated third molar removal assessment in future.

Pathologies associated with the mandibular third molar impaction.

To evaluate the associations of impaction patterns of mandibular third molars (M3Ms) with pathologies caused by them. In this study, 262 patients with 432 impacted M3Ms who referred in Shanghai Xuhui District Center were reviewed. The pathologies include pericoronitis, mandibular second molar (M2M) caries, and M2M distal periodontal pathology. The impaction patterns of M3Ms and the pathologies were examined, while the M2M outcomes after surgeries were evaluated. A χ2 test was used to analyze the data, with a p value of <0.05 being considered statistically significant. Pericoronitis was the major symptom in all patients, whereas the propensities of M2M distal caries and periodontal pathologies increased in older patients. Soft tissue impacted and vertically angulated teeth were more associated with pericoronitis (p < 0.05); mesio-angular impacted teeth in less deep positions had greater risks of M2Ms distal caries (p < 0.05); mesio-angular and horizontal impacted teeth in relative deep positions were more likely to cause M2Ms distal periodontal pathologies (p < 0.05). Extractions of soft tissue impacted teeth in vertical angulations should be considered, while removals of mesially and horizontally angulated or bony impacted teeth could be delayed.

Cross-Sectional Imaging of Third Molar-Related Abnormalities.

Third molars may be associated with a wide range of pathologic conditions, including mechanical, inflammatory, infectious, cystic, neoplastic, and iatrogenic. Diagnosis of third molar-related conditions can be challenging for radiologists who lack experience in dental imaging. Appropriate imaging evaluation can help practicing radiologists arrive at correct diagnoses, thus improving patient care. This review discusses the imaging findings of various conditions related to third molars, highlighting relevant anatomy and cross-sectional imaging techniques. In addition, key imaging findings of complications of third molar extraction are presented.

Remineralising Dentine Caries Using Sodium Fluoride with Silver Nanoparticles: An In Vitro Study.

OBJECTIVE: To investigate the remineralizing and staining effects of sodium fluoride (NaF) solution with polyethylene glycol-coated silver nanoparticles (PEG-AgNPs) on artificial dentine caries. MATERIALS AND METHODS: Demineralized human dentine blocks were allocated to three groups. The blocks in group 1 underwent a topical application of a 12% silver diamine fluoride (SDF, 14,150 ppm fluoride) solution. The blocks in group 2 received a topical application of a 2.5% NaF (11,310 ppm fluoride) with PEG-AgNPs (400 ppm silver). The blocks in group 3 received deionized water. All blocks were subjected to pH cycling for 8 days. The surface morphology and cross-sectional features were investigated using scanning electron microscopy (SEM). The color parameters, crystal characteristics, lesion depth, and collagen degradation of the blocks were assessed using digital spectrophotometry, X-ray diffraction (XRD), micro-computed tomography, and spectrophotometry with a hydroxyproline assay, respectively. RESULTS: The SEM showed that dentine collagen was exposed in group 3 but not in groups 1 and 2. The mean lesion depths in groups 1 to 3 were 118±7 µm, 121±14 µm, and 339±20 µm, respectively (groups1,2<3; p<0.001). The data indicated that fluoridated PEG-AgNPs introduced no significant color effect on dentine, but SDF caused distinct discoloration. The XRD indicated that silver chloride was formed in group 1, and fluorapatite was detected in groups 1 and 2. The concentration of hydroxyproline liberated from collagen was significantly less in groups 1 and 2 than in group 3. CONCLUSION: The use of NaF solution with PEG-AgNPs can remineralize artificial dentine caries and inhibit collagen degradation without causing significant tooth staining.

Bucco alveolar bone thickness of mandibular impacted third molars with different inclinations: a CBCT study.

PURPOSE: To compare the buccal alveolar bone thickness of mesioangulated mandibular impacted third molars (MITM) with buccal versus lingual inclination using cone-beam computed tomography (CBCT). METHODS: This retrospective cross-sectional study evaluated 69 individuals (39 women and 30 men) who presented a total of 101 mesioangulated MITM according to the Winter classification and in B position according to the Pell and Gregory classification. The average age was 22.99 ± 3.94 years. The superior, medial and inferior alveolar thickness regarding buccal (n = 44) or lingual (n = 57) mandibular third molar inclination were measured. T test or Mann-Whitney U test and finally, a multiple linear regression were applied (p < 0.05). RESULTS: The buccal alveolar bone thickness of mesioangulated mandibular impacted third molars was significantly greater in the group with lingual inclination compared to the group with buccal inclination, in the superior region (6.21 ± 3.27 vs. 4.85 ± 3.06; p = 0.036). The lingual inclination significantly influenced the buccal alveolar bone thickness in the middle region (p = 0.011). CONCLUSIONS: The mesioangulated MITM in B position with lingual inclination have a greater thickness of the superior and medial buccal alveolar bone than the MITM with buccal inclination. These results should be considered during MITM diagnosis and surgical planning.

Occlusal Caries Detection and Diagnosis Using Visual ICDAS Criteria, Laser Fluorescence Measurements, and Near-Infrared Light Transillumination Images.

OBJECTIVE: Current diagnostic tools for non-cavitated occlusal caries are not very reliable. For this reason, newer systems need to be developed. The aim of this study was to compare the performance of visual inspection (ICDAS-II), laser fluorescence (DIAGNOdent pen), and the near-infrared transillumination technique (DIAGNOcam) in the detection of non-cavitated occlusal caries lesions under clinical and laboratory conditions in 90 third molar teeth planned for extraction. MATERIALS AND METHODS: Ninety third molar teeth were firstly examined in clinical conditions, scored according to ICDAS-II criteria, and examined with DIAGNOdent pen and DIAGNOcam devices. After finishing the clinical examination, the teeth were re-evaluated shortly after the extractions with the same methods. Then, the teeth were sectioned for histological validation according to Downer's criteria. Sensitivity, specificity, accuracy, and area under the receiver operating characteristic (ROC) curves were calculated based on the histological results. RESULTS: For the D0-D1-4 threshold, the area under the ROC curve values ranged between 0.754 and 0.881 for all systems. Sensitivity values ranged between 80.5 and 96.1%, and specificity values ranged between 61.5 and 84.6% for the three caries detection methods. DIAGNOcam had the best correlation value (0.616) according to histological observations and demonstrated a sensitivity rate of 96.1%, a specificity rate of 61.5%, and an accuracy rate of 91.1%. CONCLUSIONS: DIAGNOcam was found to be the most effective method for the diagnosis of occlusal caries without cavitation in permanent molar teeth.

Evaluation of the relationship between gonial angle and impacted mandibular third molar teeth.

Mandibular third molar teeth have the highest impaction frequency for several reasons such as lack of space which may be related to the direction of facial growth. Gonial angle is used for the definition of facial growth pattern with some other measures such as mandibular plane angle. Winter and Pell-Gregory classifications are used for defining the level and pattern of mandibular third molar impaction. The aim of this study is to define the relationship between mandibular third molar impaction pattern and gonial angle; also to evaluate relationship between mandibular third molar roots and inferior alveolar canal. Study included 90 patients who had undergone cone beam computed tomography assessment for mandibular third molar impaction. Impacted teeth were grouped according to Pell-Gregory depth (A, B, C) and ramus (1, 2, 3) classification and sub-groups were composed. Winter classification was used for angulation of third molars and their relationship between with inferior alveolar canal was recorded. Gonial angle was measured on panoramic radiographs. Of the evaluated 90 impacted third molars, mesioangular position was the most frequent (34.4%), followed by vertical, horizontal and distoangular positions. Nearly 77% of the impacted third molar roots were related to inferior alveolar canal. While no correlation was determined between gender, age, third molar angulation and gonial angle, C2 sub-group of Pell-Gregory classification showed statistically significant higher gonial angle values. Although no significance was found, gonial angle was higher in level C group. In conclusion, gonial angle is higher in patients with C2 impaction level. Also, although statistically insignificant, Pell-Gregory C group had higher gonial angle averages.

Avaliação das alterações moleculares dos folículos dentários em relação à idade cronológica / Evaluation of molecular changes in dental follicles in relation to chronological age

O Folículo dental (FD) é um tecido de origem ectomesenquimal. Aproximadamente 57% dos adultos apresentam terceiro molar mandibular impactado, sendo esse elemento dentário com maior prevalência de impactação dental. Há maior incidência de alterações patológicas em indivíduos mais velhos em comparação com indivíduos mais jovens. Porém os mecanismos envolvidos na formação de cistos e tumores relacionados aos FDs não estão bem elucidados, e, por isso, alguns autores defendem a extração profilática dos terceiros molares inclusos. Durante o envelhecimento cronológico, padrões epigenéticos mudam, e um padrão de hipometilação global do DNA pode ser encontrado concomitantemente com hipermetilação de vários genes supressores tumorais. A metilação do DNA é um dos mecanismos que regula as vias de sinalização celular, como a da MAPK/ERK, que atuam no controle da proliferação e diferenciação. Alguns pesquisadores descobriram um aumento na atividade do ERK 1/2 durante o processo de envelhecimento, o que poderia contribuir para a ocorrência de doenças, e a sua desregulação está envolvida na indução e na progressão de doenças como câncer e doenças autoimunes. Portanto, o presente estudo teve por objetivo avaliar se os FDs de indivíduos jovens e indivíduos mais velhos apresentam diferença no perfil de metilação global do DNA, e avaliar o padrão de imunoexpressão da forma fosforilada ERK1/2 (pERK1/2) nos FDs. A metilação global do DNA (percentual de 5mC) e a hidroximetilação (5hmC) foram avaliadas por ELISA em 59 amostras. Testamos a correlação entre o conteúdo de 5mC e 5hmC e a correlação de cada um com a idade dos pacientes. Examinamos a imunorreatividade do pERK 1/2 para avaliar a ativação das vias MAPK/ERK em 46 amostras de FD. As amostras apresentaram variação entre 13 e 31 anos de idade. Os resultados mostraram uma relação inversamente proporcional entre o conteúdo de 5hmC e idade até os 19 anos, portanto o percentual de 5hmC nos FDs tende a diminuir linearmente com o envelhecimento. O estudo imuno-histoquímico mostrou um padrão variável de imunoexpressão de pERK1/2 com 46% (21/46) das amostras exibindo menos de 10% de células positivas, enquanto 24% (11/46) das amostrasapresentaram imunopositividade entre 10 e 50% e 30% (14/46) das amostras mais de 50% das células de FD. Não foi observado diferença nas idades entre esses grupos. Em conclusão, nossos resultados sugerem que a hidroximetilação global do DNA possui alteração no seu padrão durante o envelhecimento e que a via de sinalização celular MAPK/ERK está ativa nos FDs.

The dental follicle (DF) is a tissue of ectomesenquimal origin. Approximately 57 % of young adults have impacted third molars, which is the most prevalent impacted tooth. The incidence of pathological changes is greater among older individuals than younger individuals. However, the mechanisms behind the formation of cysts and tumors related to DFs have not been fully clarified and, therefore, some researchers defend the prophylactic extraction of third molars. During chronological aging, epigenetic patterns change and a global DNA hypomethylation pattern can be found concomitantly with hypermethylation of several tumor suppressor genes. DNA methylation is one of the regulators of cell signaling pathways, such as the MAPK/ERK pathway. Some researchers have found an increase in ERK1/2 activity during the aging process, which may contribute to the occurrence of disease, and its dysregulation is involved in the induction and progression of diseases such as cancer and autoimmune diseases. Thus, the aim of the present study was to evaluate whether DFs in young and older individuals differ in terms of global methylation and hydroxymethylation and to evaluate the immunoexpression pattern of phosphorylated ERK1/2. Global DNA methylation (5mC content) and hydroxymethylation (5hmC) were evaluated by ELISA in 59 DF samples We tested the correlation between 5mC and 5hmC content, and the correlation of each with patients' age. We examined ERK1/2 immunoreactivity for the evaluation of the activation of the MAPK pathways in 46 DF samples. Age of patients of the 59 samples of DFs raged from 13 to 31 years. An inversely proportional relation was found between the 5hmC content and age up to 19 years, therefore, the percentage of 5hmC in the DFs tends linearly decrease with aging. The immunohistochemical study showed a variable pattern of immunoexpression of pERK 1/2 with 46% (21/46) of the samples showing less than 10% of positive cells, while 24% (11/46) of the samples showed immunopositivity between 10 and 50% and 30% (14/46) of the samples greater than 50% of the DF cells. There was no difference in age among these groups. In conclusion, our results suggest that the global hydroxymethylation of DNA changes in its pattern during aging and that the MAPK/ERK cell signaling pathway is active in DFs.

Tercer molar heterotópico en el reborde orbitario: Reporte de un caso y revisión de literatura / Heterotopic third molar in the orbital rim: Report of a case and literature review

Los terceros molares heterotópicos son órganos dentarios que se encuentran en un sitio anatómico fuera de lo habitual, pueden ser supernumerarios, deciduos o un diente permanente, el cual ha sido reportado en diferentes posiciones, incluyendo la región coronoidea, cavidad nasal, seno maxilar, región orbitaria, palatina, cóndilo mandibular. La etiología de la erupción heterotópica/ectópica es desconocida, aunque hay varias teorías como la discrepancia óseo-dentaria por la evolución. Los órganos dentarios heterotópicos/ectópicos son comunes en la mandíbula y en el género femenino y pueden ocurrir en ambas denticiones. Algunos terceros molares heterotópicos/ectópicos son asintomáticos durante el periodo de vida y son usualmente detectados en hallazgos clínicos y radiográficos de manera incidental. Existen casos documentados desde 1887 hasta la actualidad cuya localización es en el reborde orbitario. En el presente artículo se expone un caso clínico de una extracción quirúrgica de un tercer molar superior heterotópico en el reborde orbitario descrita bajo el protocolo de las retenciones dentales. Dicho caso fue establecido en el Hospital Regional «General Ignacio Zaragoza¼ del ISSSTE en la Ciudad de México, con el que se obtuvieron resultados favorables, fue el primer reporte de la literatura en México. Se realizó una revisión aleatoria de la literatura en páginas como PubMed, ScienceDirect y Springer, Cochrane Library y se desarrolló el reporte de caso clínico de una paciente con un tercer molar superior heterotópico ubicado en el piso de órbita derecho (AU)

Heterotopic third molars are dental organs that are in an anatomical site out of the ordinary, can be supernumerary, deciduous or a permanent tooth, which has been reported in different positions, including the coronoid region, nasal cavity, maxillary sinus, orbital region, palatal, mandibular condyle. The etiology of the heterotopic/ectopic eruption is unknown, although there are several theories such as bone-dental discrepancy due to evolution. The heterotopic/ectopic teeth are common in the jaw and in the female gender and can occur in both dentitions. Some heterotopic/ectopic third molars are asymptomatic during the lifetime and are usually found incidentally in clinical and radiographic findings. There are documented cases from 1887 to the present that its location is in the orbital rim. In the present article we present a clinical case of a surgical extraction of a third upper molar heterotopic in the orbital rim and that is described under the dental retention protocol established in the Regional Hospital «General Ignacio Zaragoza¼ of the ISSSTE in the City of Mexico, with which they obtain favorable results, first report of the literature in Mexico. A randomized review of the literature was made on pages such as PubMed, ScienceDirect and Springer, Cochrane Library and the clinical case report of a patient with a heterotopic upper third molar located on the floor of the right orbit was developed (AU)