Lead levels in primary teeth of children living in Mexico City

OBJECTIVE

The aim of this study was to discover the lead concentration in primary teeth extracted in the peripheral clinics of the Faculty of Dentistry, UNAM (Mexico City).

DESIGN

One hundred healthy primary teeth were collected from 2 to 13-year-old children (52 girls and 48 boys). Sixty-six were maxillary teeth and 34 were mandibular teeth. Lead concentrations were measured by Graphite Furnace Atomic Absorption Spectrophotometry.

RESULTS

Our results indicate that lead concentration in the 10-13-year-old group (7.7 micro g/g(-1)) was higher than in the other groups. Geometric mean lead concentration was higher in girls than in boys (7.3 micro g/g(-1) and 6.3 micro g/g(-1), respectively). Maxillary teeth had higher lead concentrations than mandibular teeth and primary canines showed the highest mean lead concentration followed by incisors and molars. Teeth from children living in the south-east area (which according to the Mexico City's Pollution Center data is the more polluted area), presented the highest lead concentration but no statistically significant difference was found among teeth from the different areas.

CONCLUSIONS

Our results suggest that age, gender and place of residence are not related to the lead concentration in human primary teeth. This fact seems to indicate the ubiquitous presence of lead in the whole atmosphere of Mexico City and suggests that zones of residence do not appear to influence tooth lead concentration.

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.

[Fluorosis in primary dentition in a region with endemic water fluoride]

OBJECTIVE

The aim of the present study was to estimate the prevalence of dental fluorosis in primary dentition of a San Luis Potosi children population, and its association to fluoride concentration in drinking water and urine. An additional objective was, to develop, validate, and test a specific index for dental fluorosis in primary dentition.

MATERIAL AND METHODS

From May 1997, to January 1999, we conducted a cross-sectional study to assess the prevalence of dental fluorosis in primary dentition. Study subjects were 100 children aged 3-6 years, selected at random from three kindergartens in three risk areas of San Luis Potosi. The specific index of dental fluorosis for primary dentition (Dental Fluorosis for Primary Dentition Index--DFPDI) was validated by estimating fluoride concentrations in enamel of teeth with and without dental fluorosis. The Kruskal-Wallis test was used to assess the association between fluoride concentrations in drinking water and urine, with dental fluorosis; the association between risk area and dental fluorosis was assessed with the Mantel-Haenszel chi 2 test.

RESULTS

The prevalence of dental fluorosis in primary dentition was 78%; primary molars were most affected in both maxillae and the predominant color was a non-glossy white appearance. We found a strong direct correlation (r = 0.93) between fluoride concentrations in primary teeth and the DFPDI. Associations were found between fluoride concentrations of drinking water and urine, with dental fluorosis (Kruskal-Wallis p = 0.00001), and between risk area and dental fluorosis (Mantel-Haenszel chi 2 p = 0.00001).

CONCLUSIONS

DFPDI allowed adequate identification and grading of dental fluorosis in primary dentition. It is important to detect the initial toxic effects of fluoride exposure to predict dental fluorosis in permanent dentition and skeletal fluorosis.

Gingival salivary gland choristoma. A case report

Gingival salivary gland choristoma is an extremely rare disturbance of glandular development. A review of the literature disclosed only 5 reported cases of this entity and 7 gingival salivary gland tumors or alterations. We present a case of this condition present in a 43-year-old female patient, which was found while reviewing casts for the design of a prosthetic appliance. This case suggests that embryonal pluripotentiality of gingival epithelial cells is retained and that development of salivary glands in gingival tissue is feasible. An additional discussion about its histogenesis is presented.

[Bottled beverages as additional sources of exposure to fluoride]

OBJECTIVE

To evaluate and to report the concentration of floride in soft drinks and juices consumed in San Luis Potosi, S.L.P., Mexico, and its implications as a risk factor for developing dental fluorosis.

MATERIAL AND METHODS

The contents of some products from 2 main national companies and 2 other local companies were studied. The samples were collected from 10 different batches in the case of the soft drinks, and from 5 batches in the case of the juices, with 3 samples per batch, during 3 months. The ion selective electrode method was used to determine the concentration of fluoride.

RESULTS

Soft drinks from 2 main national companies showed high fluoride concentrations that were statistically significant between groups (p < 0.05). Fluoride levels of products from local and national companies also showed differences that were statistically significant between groups (p < 0.05). All natural juices tested showed high fluoride concentrations.

CONCLUSIONS

Most soft drinks and juices consumed in SLP had high fluoride levels above Mexican regulations (0.7 ppm) and could be a substantial risk factor for developing dental fluorosis.

In vivo diagnostic assessment of dentinal caries utilizing acid red and povidone-iodine dyes

In order to compare the clinical utilization of diagnostic dyes to identify carious dentin, the present in vivo study compared two caries-detector dyes, acid red (1% acid red in propylene glycol wt/wt) and povidone-iodine (8% povidone-iodine in water wt/vol). A total of 221 cavities prepared by 19 senior dental students under the supervision of two teachers at the Universidad Nacional Autónoma de México Dental School were used. Dyes were applied double-blind under standardized conditions to at least two teeth of the same patient. Data were analyzed using the Mantel-Haenszel chi-square test and a test of proportions. Results showed that molars or premolars did not appear to be positively stained more frequently by one dye or another. Also, 36.7% of teeth tested positive to either one of the two dyes. Prudent utilization of either acid red or povidone-iodine appeared to be equally useful in assisting clinical decisions concerning cavity size while restoring dentinal lesions. However, povidone-iodine may be preferred in clinical settings where acid red is expensive and/or difficult to obtain. Further research is necessary to establish accurately the mechanism of staining by povidone-iodine.