Idiopathic osteosclerosis in the maxillomandibular area.

OBJECTIVES: To test a more complete set of morphometric radiographic parameters to evaluate the idiopathic osteosclerosis (IO) lesions located in the maxillomandibular area and to know their features during routine radiographic evaluation. MATERIALS AND METHODS: Radiographs from patients attending the oral diagnosis clinic of our institution were reviewed. Evaluated parameters were gender and age of the patients, size, side, homogeneity, morphology, radiodensity, mineralization, borders, relation to roots, affected tooth or teeth and location of the analyzed lesions. RESULTS: Of the 6340 assessed patients, 354 (5.6%) harbored 362 lesions. IOs were more common during 2nd to 4th decades (mean age = 39 years). IO frequency rose from 1st to 3rd decades and then decreased. Size varied from 0.1 to 5.8 cm, and its frequency increased from 7 to 30 years age and then decreased too. The mandible and molar region were more commonly affected. Radiopaque image, radicular location, round shape, homogeneous core and well-defined boundaries were the more frequent IO features. CONCLUSIONS: Our method allows to analyze IO lesions with precise parameters. Analysis of the results does not support the previously suggested theories to explain their origin, and these figures suggest that the so-called IOs are developmental alterations of the bone.

Squamous cell carcinoma of the tongue in patients older than 45 years.

This study aims to evaluate the clinicopathological features, TNM status, AJCC staging and behavior of squamous cell carcinoma of the tongue (SCCT) in patients older than 45 years. The files of the Department of Pathology of the Hospital General de México were reviewed and all cases of SCCT in patients older than 45 years were selected. Clinicopathological features, treatment, follow-up, microscopic diagnosis, and IJCC and TNM staging were retrieved. Complete data from 60 cases were evaluated. They were more common in males (mean age = 63.9 years). Unexpectedly a high rate of tumors (38.3%) were in the base of the tongue (BT). Moderately and poorly differentiated SCCT were the most common. 16.7% presented lymph node invasion, 15% were recurrent tumors and BT carcinomas recurred more frequently. A high rate (81.7%) were stage II and 48.3% were low-risk patients. SCCTs in the studied population displayed different clinico-pathological and behavioral features compared with worldwide data. Our results suggest that BT tumors should be treated more aggressively than those in the mobile tongue. BT located tumors were more frequent than previously published. Additional frequency studies will define outcomes in age cohorts with a consensus cut-off for young and elderly populations. More population-based studies should be performed in Latin American regions to acquire accurate data on SCC incidence in elder subpopulations and to identify precisely the etiological factors in these patients.

Frequency of dilaceration in a mexican school-based population.

BACKGROUND: The aim of this study was to record the frequency of dilaceration in patients attending our institution and to analyze the possible associated factors. MATERIAL AND METHODS: Orthopantomograms from all patients attended in our institution were reviewed and those cases of dilaceration were selected. Documented data were age, gender, diagnosis, location and involved teeth. Data on possible etiological factors was also recorded. RESULTS: 125 dilacerated teeth in 99 patients were found. Dilacerations were more commonly detected in females and in maxillary teeth. Maxillary 2nd bicuspids and lateral incisors were the more commonly affected teeth and were more common in teeth with predecessors (anterior teeth and bicuspids). Traumatic episodes and caries of the predecessor teeth was mentioned but never were related with affected teeth. CONCLUSIONS: Data from the studied population are different compared to previously published studies. Our results support the point of view that the occurrence of dilacerated teeth could be related to limited availability of space to allocate the erupting teeth in the dental arch and perhaps to the possibility of the tooth to rotate, preventing eruption. Key words:Developmental alterations, dental developmental alterations, root dilaceration.

Length of the ossified stylohyoid complex and Eagle syndrome.

PURPOSE: To assess radiographically the presence of an ossified stylohyoid complex (OSHC) with signs and symptoms of Eagle syndrome or other oro-facial painful diseases in patients attending our institution and to confirm that the important issue for study is to know the length of the ossificated portion of the stylohyoid complex only. METHODS: We separated 1000 consecutive files, and after selection, 922 panoramic radiographs were evaluated. Assessed parameters were gender and age of the patients, size, and location of the analyzed OSHCs. In addition, the length parameters of the studied OSHCs were also determined in 100 extra radiographs. RESULTS: Normal length of OSHCs was between 2.83 and 4.16 cm and OSHCs measuring more than 4.17 cm long comprising 23.2% of the sample. Any of the patients with OSHC presented signs or symptoms of the Eagle syndrome or any other orofacial painful disease. CONCLUSIONS: This is the first study on OSHCs using the mandatory parameters of normal, short and elongated length in the studied population. Our results suggest that the presence of an OSHC is not an important feature for pain detection in the Eagle syndrome and is not an important risk factor for development of throat pain in this and other painful orofacial diseases. Our results are different from those previously published in other populations and suggest that the widely used lengths of 2 to 4 cm for measuring the OSHCs are not adequate parameter. It is desirable to define first the short, normal and abnormal parameters of OSHCs in each studied population.

Maxillomandibular giant osteosclerotic lesions.

INTRODUCTION: Giant Osteosclerotic Lesions (GOLs) are a group of rarely reported intraosseous lesions. Their precise diagnosis is important since they can be confused with malignant neoplasms. OBJECTIVE: This retrospective study aimed to record and analyze the clinical and radiographic Giant Osteosclerotic Lesions (GOLs) detected in the maxillomandibular area of patients attending to our institution. Materials and Methods: Informed consent from the patients was obtained and those cases of 2.5 cm or larger lesions with radiopaque or mixed (radiolucid-radiopaque) appearance located in the maxillofacial bones were selected. Assessed parameters were: age, gender, radiographic aspect, shape, borders, size, location and relations to roots. Lesions were classified as radicular, apical, interradicular, interradicular-apical, radicular-apical or located in a previous teeth extraction area. Additionally, several osseous and dental developmental alterations (DDAs) were assessed. RESULTS: Seventeen radiopacities in 14 patients were found and were located almost exclusively in mandible and were two types: idiopathic osteosclerosis and condensing osteitis. GOLs were more frequent in females, and in the anterior and premolar zones. 94.2% of GOLs were qualified as idiopathic osteosclerosis and one case was condensing osteitis. All studied cases showed different osseous and dental developmental alterations (DDAs). The most common were: Microdontia, hypodontia, pulp stones, macrodontia and variations in the mental foramina. CONCLUSIONS: GOLs must be differentiated from other radiopaque benign and malignant tumors. Condensing osteitis, was considered an anomalous osseous response induced by a chronic low-grade inflammatory stimulus. For development of idiopathic osteosclerosis, two possible mechanisms could be related. The first is modification of the normal turnover with excessive osseous deposition. The second mechanism will prevent the normal bone resorption, arresting the osseous breakdown process.

Squamous cell carcinoma of the tongue in patients older than 45 years

Abstract: This study aims to evaluate the clinicopathological features, TNM status, AJCC staging and behavior of squamous cell carcinoma of the tongue (SCCT) in patients older than 45 years. The files of the Department of Pathology of the Hospital General de México were reviewed and all cases of SCCT in patients older than 45 years were selected. Clinicopathological features, treatment, follow-up, microscopic diagnosis, and IJCC and TNM staging were retrieved. Complete data from 60 cases were evaluated. They were more common in males (mean age = 63.9 years). Unexpectedly a high rate of tumors (38.3%) were in the base of the tongue (BT). Moderately and poorly differentiated SCCT were the most common. 16.7% presented lymph node invasion, 15% were recurrent tumors and BT carcinomas recurred more frequently. A high rate (81.7%) were stage II and 48.3% were low-risk patients. SCCTs in the studied population displayed different clinico-pathological and behavioral features compared with worldwide data. Our results suggest that BT tumors should be treated more aggressively than those in the mobile tongue. BT located tumors were more frequent than previously published. Additional frequency studies will define outcomes in age cohorts with a consensus cut-off for young and elderly populations. More population-based studies should be performed in Latin American regions to acquire accurate data on SCC incidence in elder subpopulations and to identify precisely the etiological factors in these patients.

Maxillomandibular giant osteosclerotic lesions

Abstract Giant Osteosclerotic Lesions (GOLs) are a group of rarely reported intraosseous lesions. Their precise diagnosis is important since they can be confused with malignant neoplasms. Objective This retrospective study aimed to record and analyze the clinical and radiographic Giant Osteosclerotic Lesions (GOLs) detected in the maxillomandibular area of patients attending to our institution. Materials and Methods: Informed consent from the patients was obtained and those cases of 2.5 cm or larger lesions with radiopaque or mixed (radiolucid-radiopaque) appearance located in the maxillofacial bones were selected. Assessed parameters were: age, gender, radiographic aspect, shape, borders, size, location and relations to roots. Lesions were classified as radicular, apical, interradicular, interradicular-apical, radicular-apical or located in a previous teeth extraction area. Additionally, several osseous and dental developmental alterations (DDAs) were assessed. Results Seventeen radiopacities in 14 patients were found and were located almost exclusively in mandible and were two types: idiopathic osteosclerosis and condensing osteitis. GOLs were more frequent in females, and in the anterior and premolar zones. 94.2% of GOLs were qualified as idiopathic osteosclerosis and one case was condensing osteitis. All studied cases showed different osseous and dental developmental alterations (DDAs). The most common were: Microdontia, hypodontia, pulp stones, macrodontia and variations in the mental foramina. Conclusions GOLs must be differentiated from other radiopaque benign and malignant tumors. Condensing osteitis, was considered an anomalous osseous response induced by a chronic low-grade inflammatory stimulus. For development of idiopathic osteosclerosis, two possible mechanisms could be related. The first is modification of the normal turnover with excessive osseous deposition. The second mechanism will prevent the normal bone resorption, arresting the osseous breakdown process.

Unusually high incidence of multifocal epithelial hyperplasia in children of the Nahuatl population of Mexico.

BACKGROUND: Multifocal epithelial hyperplasia is an uncommon disease of the oral mucosa caused by the human papilloma virus. AIM: To study the clinical and pathological findings of multifocal epithelial hyperplasia detected during an oral examination of 343 Mexican Nahuatl children from a single primary school in El Paso de Cupilco, Mexico. METHODS: A thorough oral examination was performed in all children and clinical data (age, gender, location and number of lesions) were documented and analyzed. RESULTS: Multifocal epithelial hyperplasia was diagnosed in 110 of the 343 children (32.3%). The ages of the children varied from 5 to 15 years, and of these, 56.3% were girls. The lesions were asymptomatic, 0.2 to 3.0 cm in diameter, soft, round to oval, smooth surfaced, sessile papulonodules, similar in colour to that of the surrounding mucosa. The lesions were commonly seen on the buccal mucosa and tongue, and most affected children (85%) had less than 5 lesions. Children in the 7 to 10 years age group were most often affected. LIMITATIONS: Human papillomavirus typing was not done owing to a lack of facilities. CONCLUSIONS: There is a high incidence of multifocal epithelial hyperplasia in Nahuatl children with a predilection for females.

Scanning Electron Microscopic Study on the Fibrillar Structures within Dentinal Tubules of Human Dentin.

INTRODUCTION: Pulp biology is central to the whole tooth, and knowledge on its microstructure is changing with new studies. This study presents certain microfibrillar structures found within the dentin tubules of human teeth connecting dentin tubules and odontoblastic processes. METHODS: We analyzed the crowns of 30 noncarious, human teeth. They were fixed; demineralized; and, later, processed and reviewed by means of scanning electron microscopy. RESULTS: In the predentin layer, we found numerous fine fibrillar structures connecting the odontoblastic process and the wall of the dentinal tubule. In the inner dentinal third, we observed structures forming a dense microfibrillar network of variable thickness and diameters. These microstructures were very thin and numerous in this area, and their number decreased as more external dentin levels were examined. CONCLUSIONS: According to the review of the literature and our findings, these microfibrillar structures may be an unrecognized support system that holds and secures the odontoblastic process within the dentinal tubule.

MUC-1 expression in pleomorphic adenomas using two human milk fat globule protein membrane antibodies (HMFG-1 and HMFG-2).

UNLABELLED: Pleomorphic adenoma (PA) is the most common salivary gland tumor and its microscopic features and histogenesis are a matter of debate. Human milk fat globule protein membrane (HMFG) monoclonal antibodies (MoAbs) comprise a set of antibodies against the mucin 1 (MUC-1) protein detected in several salivary gland tumors. OBJECTIVE: The aim of this study was to assess the immunoexpression of the PA neoplastic cells to MUC-1 protein using HMFG-1 and HMFG-2 MoAbs, contrasting these results with those from normal salivary gland tissue. MATERIAL AND METHODS: Immunohistochemical detection of MUC-1 protein using HMFG-1 and HMFG-2 MoAbs was made in 5 mm thick, paraffin embedded slides, and the avidin-biotin method was used. RESULTS: Positivity to HMFG-1 and HMFG-2 MoAbs was found in ductal, squamous metaplastic and neoplastic myoepithelial cells, keratin pearls and intraductal mucous material. Two kinds of myoepithelial cells were identified: classic myoepithelial cells around ducts were negative to both MoAbs, and modified myoepithelial cells were positive to both MoAbs. This last cellular group of the analyzed tumors showed similar MUC-1 immunoexpression to ductal epithelial cells using both HMFG antibodies. Intraductal mucous secretion was also HMFG-1 and HMFG-2 positive. CONCLUSIONS: Our results showed there are two kinds of myoepithelial cells in PA. The first cellular group is represented by the different kinds of neoplastic myoepithelial cells and is HMFG-positive. The second one is HMFG-negative and represented by the neoplastic myoepithelial cells located around the ducts.

MUC-1 expression in pleomorphic adenomas using two human milk fat globule protein membrane antibodies (HMFG-1 and HMFG-2)

Pleomorphic adenoma (PA) is the most common salivary gland tumor and its microscopic features and histogenesis are a matter of debate. Human milk fat globule protein membrane (HMFG) monoclonal antibodies (MoAbs) comprise a set of antibodies against the mucin 1 (MUC-1) protein detected in several salivary gland tumors. Objective The aim of this study was to assess the immunoexpression of the PA neoplastic cells to MUC-1 protein using HMFG-1 and HMFG-2 MoAbs, contrasting these results with those from normal salivary gland tissue. Material and Methods Immunohistochemical detection of MUC-1 protein using HMFG-1 and HMFG-2 MoAbs was made in 5 mm thick, paraffin embedded slides, and the avidin-biotin method was used. Results Positivity to HMFG-1 and HMFG-2 MoAbs was found in ductal, squamous metaplastic and neoplastic myoepithelial cells, keratin pearls and intraductal mucous material. Two kinds of myoepithelial cells were identified: classic myoepithelial cells around ducts were negative to both MoAbs, and modified myoepithelial cells were positive to both MoAbs. This last cellular group of the analyzed tumors showed similar MUC-1 immunoexpression to ductal epithelial cells using both HMFG antibodies. Intraductal mucous secretion was also HMFG-1 and HMFG-2 positive. Conclusions Our results showed there are two kinds of myoepithelial cells in PA. The first cellular group is represented by the different kinds of neoplastic myoepithelial cells and is HMFG-positive. The second one is HMFG-negative and represented by the neoplastic myoepithelial cells located around the ducts. .

P53 and bcl-2 immunoexpression in patients with oral lichen planus and oral squamous cell carcinoma.

OBJECTIVE: The aim of this study was to determine by immunohistochemistry the presence and significance of p53 and bcl-2 proteins in oral lichen planus (OLP) and oral squamous cell carcinoma (OSCC). STUDY DESIGN: We used 21 cases diagnosed as OLP 16 diagnosed as OSCC and four normal gingival biopsies taken from healthy patients were used as controls. Slides were processed for immunohistochemistry using anti-p53 and anti-bcl-2 monoclonal antibodies. RESULTS: We found p53 immunoexpression in 71.4% OLP cases and 68.7% OSCC cases, with no immunoexpression in control cases. Bcl-2 was negative for all OLP and OSCC cases, and mild positivity was observed in normal tissue. We found significant correlation among p53 expression and OSCC malignancy. CONCLUSIONS: Our results suggest that TP53 system mainly promotes a hyperproliferative state by cell cycle arrest of the OLP epithelial cells for repairing damaged DNA nor apoptosis and that anti-apoptotic action of bcl-2 is not important in this disease.

Central odontogenic fibroma: new findings and report of a multicentric collaborative study.

OBJECTIVE: The aim of this study was to describe the clinicopathologic and immunohistochemical characteristics of 14 cases of central odontogenic fibroma (COF), and the ultrastructural features of 2 of them. STUDY DESIGN: Collaborative retrospective study based on the records of 4 oral pathology diagnostic services in Latin America based on the current World Health Organization classification. RESULTS: There were 7 male and 7 female patients (mean age 31.8 years). Eight tumors occurred in the maxilla and 6 in the mandible. Thirteen cases were epithelium-rich and 1 epithelium-poor COF. Three were classified as hybrid COF with giant cell lesion. Mean size of the hybrid lesions were larger than pure COF (3.8 vs. 2.4 cm). Odontogenic epithelial islands were immunoreactive for cytokeratin (CK) AE1/AE3, CK5, CK14, CK19, and 34BE12 and negative for CK1 and CK18. Langerhans cells positive for S-100 and CD1a were found within the epithelial islands in 6/6 tested cases. CD68 was expressed in the giant cells of the hybrid lesions and in a few mononuclear cells of 2 cases of COF. Ki-67 index was <1% in all cases. In 6 tumors (42.8%), there were small globular eosinophilic droplets within the epithelial islands, which were positive for collagen type IV, and 9/13 cases (69.2%) were focally positive for smooth muscle actin. In addition to fibroblasts, myofibroblastic differentiation was found in the 2 cases studied ultrastructurally. CONCLUSIONS: Immunohistochemistry was useful to confirm the presence of epithelium and to exclude other central fibrous tumors. COF also contains a variable number of mast cells, Langerhans cells, and myofibroblasts, and further studies are needed to better understand the participation of these cells in COF histogenesis.

Fluoride content in table salt distributed in Mexico City, Mexico.

OBJECTIVE: The aim of this study was to analyze table salt available in Mexico City's market to identify the fluoride concentrations and to compare these with the Mexican regulations. METHODS: We analyzed 44 different brands of table salt. All samples were purchased at random in different stores, supermarkets, and groceries from Mexico City's metropolitan area and analyzed in triplicate in three different laboratories (nine determinations per sample) with an Orion 720 A potentiometer and an Orion 9609 BN ion-specific electrode. RESULTS: Fluoride concentration in the samples varied from 0 ppm to 485 ppm. It was found that fluoride concentration varied widely among the analyzed brands. Also, we found that fluoride concentration in 92 percent of the analyzed samples did not match with that printed on the label. Only 6.8 percent of the analyzed samples contained fluoride concentrations that meet Mexican and WHO regulations. CONCLUSIONS: The broad variation in the analyzed samples suggests that Mexican Public Health authorities must implement more stringent regulation guidelines and procedures for controlling the distribution of salt and its fluoride concentration for human consumption.

Clinicopathological and immunocytochemical study of multifocal epithelial hyperplasia.

PURPOSE: We present the clinicopathological findings after reviewing 52 patients affected by multifocal epithelial hyperplasia (MEH), previously known as focal epithelial hyperplasia and the results of an immunocytochemical study. PATIENTS AND METHODS: We reviewed the clinical files and microscopic slides from 52 MEH-affected patients and new slides were immunostained with a polyclonal antibody against high molecular weight cytokeratins. RESULTS: More than 95% of the patients were in poverty (<200 dollars monthly family income). Females comprised 71.1% of the MEH patients, 69.3% were in the first and second decades and buccal mucosa, lips, and tongue were more frequently affected. Ninety-two percent of the patients had a direct relative with similar lesions. In hematoxylin and eosin-stained slides, prominent multiple nucleoli were observed. Immunocytochemical study showed differences in immunostaining between lesional and normal cells. Cells with strongly immunostained cytoplasm were seen in the prickle layer of the lesional epithelium as well as in the clinically normal neighboring epithelial tissue. Cytokeratin-negative mitosis-like cells and koilocytes were identified within the lesions. CONCLUSIONS: The name "multifocal epithelial hyperplasia" is more accurate than those previously proposed designations, because it is more precise to describe the clinical and microscopic features of the disease. Also, our results suggest that mitosis-like cells and koilocytes are degenerated cells unable to synthesize cytokeratins and that cells with strongly immunostained cytoplasm represent epithelial cells showing an altered cytokeratin metabolic profile.

Sialolitiasis de glándula sublingual: presentación de un caso clínico y revisión de la literatura / Sialolithiasis of sublingual gland: report of a clinical case and review of the literature

La sialolitiasis es una enfermedad de presentación esporádica que se manifieta con mayor frecuencia en pacientes de sexo masculino y se asocia principalmente con las glándulas salivales mayores. Clínicamente, el sitio afectado presenta aumento de volumen, de consistencia dura, móvil, fácilmente desplazable y a veces doloroso. En este artículo se reporta un caso de uon paciente masculino de 20 años de edad con un sialolito de un año de evolución, localizado en una de las glándulas sublinguales. Se llevó a cabo la remoción quirúrgica del cálculo, sin ninguna complicación y se realizó el examen microscópico. Se efectúa seguimiento del paciente y al año no se encontró evidencia clínica o radiográfica de recurrencia. En la discusión se analizan las principales características clínicas de esta enfermedad, su tratamiento, pronóstico y se hace énfasis en que su tratamiento debe de ser realizado por un cirujano maxilofacial experimentado

Multifocal epithelial hyperplasia. Report of nine cases.

Multifocal epithelial hyperplasia (MEH) is also known as focal epithelial hyperplasia, Heck's disease or multifocal papillomavirus-induced epithelial hyperplasia. It is characterised by the presence of multiple lesions in the oral mucosa of children and it has been associated with the presence of the human papillomavirus. The aim of this study was to determine the clinico-pathological features of the cases diagnosed as MEH in the Service of Dermatology of the Hospital Manuel Gea González (SDHMGG). The files of the SDHMGG were reviewed and all cases diagnosed as MEH were retrieved. Nine MEH cases were found. Most of the patients were 20 year-old or younger (67%) and females were more commonly affected (78%). All patients presented multiple lesions and always, close relatives with similar lesions were found. Lesions were located most commonly in the buccal mucosa, lower lip and commissures. MEH is a soft tissue intraoral condition that needs treatment solely of the traumatised lesions or those with cosmetic problems. Remaining lesions will disappear with the age of the patients. It is suggested that this entity should be named multifocal epithelial hyperplasia since this name describes better the clinico-pathological and microscopic features of the disease.

Fluoride concentration in toothpastes of the Mexican market / Concentración de fluor en las pastas dentales que se venden en México

Introduction. The most widely used method for applying fluoride (F-) topically is the fluoridated toothpaste. Its early use in large quantities is a risk factor for dental fluorosis. Objective: to determine the actual concentration of F in toothpastes sold in the Mexican market. Material and methods. Sixty-five different commercial toothpastes were analysed using the F ion-specific electrode technique. Results. The range of the F content was from 0 to 2 053 ppm. Of them, 16.92% were toothpastes for infant use (range= 0-1153 ppmF-). Mexican toothpastes had a mean of 879 ± 599.2 ppmF and imported toothpastes have a mean of 619.7 ppmF-; 54.5% of the infantile toothpastes presented F concentrations above 730 ppm and in 40% of the analyzed products, annotation on F content was found. Conclusions. Our results showed a wide variation in F concentration and suggest the need to implement policies to regulate the F concentration in these products. It is important that all the manufactured dentifrices show in the label and package the total F content of the product and the recommended doses will be printed, in order to prevent dental fluorosis.

Introducción. El método más usado para la aplicación tópica de flúor (F-)es la pasta dental fluorada. Su uso temprano en grandes cantidades es un factor de riesgo de fluorosis dental. Objetivo: conocer la concentración de P en las pastas dentales que se venden en México. Material y métodos. Se analizaron 65 pastas dentales usando la técnica del electrodo específico para fluoruros. Resultados. El contenido de fluoruro en la muestra analizada varió de 0-2053 ppm. De ellas, 16.92% fueron pastas para uso infantil (límite =0 -1153 ppmF-). Las pastas fabricadas en México tuvieron un promedio de 879 ± 599.2 ppmF-. Las pastas de origen extranjero tenían un promedio de 619.7 ppmF-; 54.5% de las pastas para niños presentaron valores de P superiores a 730 ppmF-. Solamente 40% de los productos analizados tenían impresa la concentración de P en las envolturas. Conclusiones. Nuestros resultados mostraron una amplia variación en la concentración de P. Esto sugiere que es necesario implementar medidas que regulen su concentración en dichos productos. Es importante que, para prevenir lesiones de fluorosis dental, los fabricantes de pastas dentales impriman en la etiqueta el contenido total de fluoruro y las dosis recomendadas.

Frequency of supernumerary teeth in Mexican population.

Supernumerary teeth (ST) are a not uncommon developmental anomaly which appears in 0.3 to 3.8 percent of the population. We studied the corresponding radiographs from 2241 patients, both sexes who seeked dental attention at the Outpatient Clinic of the División de Estudios de Posgrado e Investigación, Facultad de Odontología, UNAM in Mexico City. Of them, we found 72 patients (3.2%) with 102 ST. Of the 72 patients, 39 were males (54.2%) and 33 females (45.8%). Mesiodens was the most common ST (48.6%), followed by supernumerary premolars (26.4%), supernumerary laterals (11.1%) and fourth molars (9.7%). This series includes cases with one, two and three ST and one case comprising 10 ST. Our results suggest that frequency of ST in the population studied differs in some aspects with previously reported series and that frequency of ST shows different rates depending the population studied. As our results demonstrate, it is encouraged the need to have panoramic radiographs of all patients attended in dental offices, clinics and schools of Dentistry in order to detect and diagnose undiscovered pathologies.