Maricela Garcés-Ortíz

Clinico-Pathologic Study of Odontogenic Cysts in a Mexican Sample Population

BACKGROUND Odontogenic cysts are uncommon lesions that frequently behave agressively and attain a large size. Unfortunately, information on the relative incidence of these cysts from different populations is not abundant. In Mexico, for example, only a few examples have been reported. The aim of this study was to ascertain the frequency of odontogenic cysts in a Mexican sample and to compare these data with previously reported studies from other countries. METHODS The files of the Oral and Maxillofacial Pathology Diagnosis Service at the School of Dentistry at the Universidad Nacional Autónoma de México (UNAM) were reviewed and all accessions of odontogenic cysts were listed. Clinical and radiographic data were recorded and microscopic slides evaluated according to the most recent World Health Organization (WHO) classification (1992). RESULTS Three hundred and four cases of odontogenic cysts (55.9% male predominance) were found. The most frequent odontogenic cysts were the following: periapical cyst (38. 8%); dentigerous cyst (35.5%), and odontogenic keratocyst (18.8%). Periapical cyst was more frequent in females, and maxillary anterior teeth were most commonly involved. Dentigerous cysts appeared in males at a rate of 64.8%, this cyst found more frequently between the 1st and 2nd decades of life and in the molar zone. Odontogenic keratocyst was more frequent in males (59.6%), between the 2nd and 4th decades of life and more common in the molar zone. CONCLUSIONS More than 50% of the sample were aggressive cysts (dentigerous and keratocyst). Our results suggest that Mexican patients develop aggressive odontogenic cysts more commonly than other populations. Our figures point to the need for a precise diagnosis in order to institute the correct surgical procedure, prevent recurrence, and forestall more extensive tissue destruction.

Multifocal epithelial hyperplasia

Dear Editor, In 1956, Estrada reported on the presence of multiple intraoral soft tissue lesions discovered in Colombian Caramanta Indians.[1] Later, Soneira and Fonseca reviewing Venezuelan Indians, found 54 patients with oral papulo-nodular lesions. They must be credited with the first complete description of this entity and suggested this disease was of viral origin.[2] Afterwards, this disease was found in several ethnic groups.[3] Multifocal epithelial hyperplasia (MEH) appears more commonly in children, but there are some communications in adults. It is characterized by the presence of multiple slow growing, papulo-nodular, elevated, and smooth surfaced asymptomatic lesions. Usually, they are sessile, round, or oval, well defined nodules with color similar to the normal mucosa, measuring from 0.1 to 0.5 cm in diameter. Coalescence of several small swellings gives rise to multinodular lesions of several centimeters. It is characteristic that isolated nodules disappear when they are stretched.[3–6] MEH is more common in females and the more frequently affected locations are labial, lingual, and buccal mucosas.[4,6] It is well known that MEH lesions are regularly associated with human papillomavirus types 13 and 32.[7] Microscopically, MEH is composed by a parakeratinized, acantotic, stratified squamous epithelium with numerous koilocytes, and mitosis-like cells. We reviewed three healthy, Mexican Mestizo children living in Mexico City urban area. One was a 14-years-old boy. His oral mucosa displayed several slow growing, asymptomatic, slightly elevated, sessile, soft, smooth surfaced lesions with the same color of the surrounding mucosa, present during 4 years. Lesions were located in tongue, lower and upper lips mucosa, and buccal mucosa [Figure 1a]. One cousin presented similar lesions. Other was a 12-years-old girl. She exhibited several smooth surfaced, elevated, sessile, asymptomatic, slow growing lesions, seen during 6 months in her buccal mucosa and lower lip [Figure 1b]. Two cousins showed similar lesions and, a 10-years-old boy complaining on the presence of numerous slightly elevated, soft, sessile, asymptomatic, pale pink in color, and well defined lesions in his buccal and lower lip mucosas of 5 months duration was reviewed. He informed that new lesions appeared during the last 15 days [Figure 1c]. Three brothers and two cousins presented identical lesions; no permission for biopsies in the relatives was obtained. Figure 1 (a) Case 1. Numerous lesions in tongue and lips mucosa are observed (b) Case 2. Elevated, sessile lesions in lower lip mucosa are seen (c) Case 3. Pale pink lesions in buccal mucosa are observed Characteristically, when we stretched the isolated lesions, they disappeared. After 3 years follow-up, no changes in the number and size of the lesions were seen. One lesion each patient was biopsied by local anesthesia, immersed in aqueous neutral formalin solution, and routinely processed to obtain H and E stained slides. Microscopic examination showed the presence of parakeratinized squamous stratified epithelium with marked acantosis. Also, thick epithelial rete ridges and numerous koilocytes were observed [Figure 2a]. Mitosis-like cells were identified accompanied with epithelial cells showing two nucleoli [Figures ​[Figures2b2b and ​andc].c]. Final diagnosis in all three cases was MEH. Figure 2 (a) Photomicrograph showing a hyperplastic, acantotic, stratified squamous cell epithelium with numerous koilocytes. H and E. 100× (b) High power photomicrograph of a rete peg showing a mitosis-like cell. H and E. 200× (c) Photomicrograph ... As the name MEH indicates, the most prevalent clinical finding is the presence of multiple nodular lesions in the oral mucosa. This disease affects lips, buccal mucosa, tongue and commissures, and is more common in children.[4–6] Actual data support that the HPV types 13 and 32 are the causative agents.[7] Families with several affected relatives are almost always found. MEH shows preference by economically poor population with deficient medical care and limited access to the health system,[3,4,6] These findings support the theory that a viral infection is the etiological agent. In our experience, if the relatives are reviewed, always some of them present, or presented MEH lesions.[3–5] It has been reported that only HPV-13 was present in Mexican population.[8] The usual treatment for MEH has been the surgical excision but actually there is a general agreement that MEH lesions should not be excised, because it is a self-limiting disease and since lesions will disappear with the age of the patient, we consider that only lesions in traumatized areas should be prophylactically excised. We believe that the name MEH proposed by our study group[3–5] should be adopted since it describes both, its main clinical feature (the presence of multiple lesions) and its main microscopic finding (epithelial hyperplasia). Several years ago, our study group suggested that the presence of familial MEH lesions could be related to the common use of knives, forks, and spoons and that transmission could be associated with the use of these contaminated objects.[2,5] This point of view is supported by reports in the presence of HPV-13 in saliva of affected patients.[8] It is important to diagnose adequately this disease, since it is frequently confused with the so-called “florid oral papillomatosis”, vulgar verrucae, papilloma, condiloma acuminatum, or lesions related to child abuse.[9] In our experience, any of the children with MEH had lesions similar to the above mentioned entities and we consider that this disease should not be related with children sex abuse.

Gingival compound odontoma

Peripheral odontomas arising in gingival tissue are very rare; only three have been reported to date. The case of a peripheral odontoma arising in the gingiva of a 3-year-old girl is presented.

Presence of matrix vesicles in the body of odontoblasts and in the inner third of dentinal tissue: A scanning electron microscopyc study

Objectives: The aim of this report is to present the results of a scanning electron microscopic study on the presence of matrix vesicles (MVs) found in human dentine. Study Design: Dentin tissue from 20 human bicuspids was analyzed by means of scanning electron microscopy. Results: MVs were found as outgrowths of the cellular membrane of the odontoblastic body, the more proximal portion of the odontoblastic process before entering the dentinal tubule and in the odontoblastic process within the inner third of the dentin. Size of MVs varied depending on location. In the inner third of dentin, they were seen in diverse positions; as membranal outgrowths, deriving from the odontoblastic process, lying free in the intratubular space and attached to the dentinal wall. Sometimes, they were seen organized forming groups of different sizes and shapes or as multivesicular chains running from the surface of the odontoblastic process to the tubular wall. MVs were present in places never considered: 1) the body of odontoblasts; 2) the most proximal part of the odontoblastic processes before entering the circumpulpal dentine and also: 3) in the inner third of dentinal tissue. Conclusions: According to our results, MVs not only participate during mantle dentin mineralization during early dentinogenesis, they also contribute during the mineralization process of the inner dentin. Key words:Dentin, microvesicles, secretory vesicles, dentin formation, dentin secretion.

Scanning Electron Micrographic Features of a Giant Submandibular Sialolith

To recognize recently appearing mineralization phenomena, one must study the external surface of the sialoliths, since it is not possible to study them in the central portions of sialoliths. The authors examined the external surface of a sialolith by scanning electron microscopy and analyzed its microstructures. The study revealed the presence of numerous microstructures of different shapes (nodular, laminar, reticular, microgranular, and multinodular) and variable size arranged in a haphazard fashion. The diverse microstructures encountered strongly suggest that different mechanisms of mineralization occur during growth and development of the sialoliths.

Cytotoxicity of Ketac Silver Cement

The aim of this experiment was to investigate the effect of a glass ionomer cement with silver particles (Ketac Silver) on pulp tissue. Class V cavities were prepared in 60 healthy teeth scheduled for extraction for orthodontic reasons. A base of Dycal was placed in each cavity. Thirty teeth were filled with Ketac Silver and 30 with ZOE. Ten teeth of each group were extracted 15, 30, and 60 days later. At 15 days, the pulps in the Ketac group showed vacuolization and disruption of the odontoblastic layer, edema, vasodilation, chronic inflammatory infiltrate (CII), and necrosis. At 30 days, a necrotic odontoblastic layer, severe CII, and extensive areas of necrosis were seen. At 60 days, pulp tissue was almost completely necrotic. The ZOE control group showed a slight CII at 15 days. Our results suggest that under these experimental conditions, this cement is highly toxic and induces irreversible pulpal damage.

Study on frequency of dental developmental alterations in a Mexican school-based population.

Background The aim of this study was to know the distribution of dental developmental alterations in the population requesting stomatological attention at the Admission and Diagnosis Clinic of our institution in Mexico City. Material and Methods We reviewed the archives and selected those files with developmental dental alterations. Analyzed data were diagnoses, age, gender, location and number of involved teeth. Results Of the 3.522 patients reviewed, 179 (5.1%) harbored 394 developmental dental alterations. Of them, 45.2% were males and 54.8% were females with a mean age of 16.7 years. The most common were supernumeraries, dental agenesia and dilaceration. Adults were 30.7% of the patients with dental developmental alterations. In them, the most common lesions were agenesia and supernumeraries. Mesiodens was the most frequently found supernumerary teeth (14.7%). Conclusions Our finding that 30.7% of the affected patients were adults is an undescribed and unusually high proportion of patients that have implications on planning and prognosis of their stomatological treatment. Key words:Developmental dental alterations, developmental alterations, supernumerary teeth, dental agenesia, root dilaceration.

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)

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.

Developmental Alterations of Teeth in Young Patients

Research motivation: The objective of this study was to know the frequency of dental developmental alterations in Mexican children and adolescents attending the Stomatological Clinics of the Faculty of Dentistry of the Universidad Nacional Autonoma de Mexico. Research design/methodology: The files of the patients attended in our institution were reviewed and 128 were from patients among 2 and 18 years old with dental developmental alterations were selected. Data on diagnosis, age, gender and involved tooth were analyzed by Students T test and p<0.05 was considered significant. Main findings: The most frequent dental developmental alterations were: supernumeraries, missing teeth and fused teeth. Other entities were also found. Prevalence of dental alterations in the sample was 29.8% and 217 dental alterations were diagnosed. Of 217 teeth, 83.4% were permanent and 16.6% were deciduous teeth. Implications: Data obtained from this study will address the consciousness of the authorities and personnel of the institutions involved in providing health services on the importance to conduct imagenologic studies in children and adolescent population for early recognition of the intrabony pathological conditions.