Insecticide residues in stored grains in Sonora, Mexico: quantification and toxicity testing.

Food safety has acquired great attention by food importer and exporters. Food rejection or acceptance across international borders is based on the compliance with international food regulations. Due to the lack of recent data on pesticide residues in Mexican grains, this study focused on detecting and quantifying insecticide residues in stored wheat, corn, chickpeas, and beans, as well as to determine their mutagenic potential. Grains were sampled from primary storage sites in Sonora, Mexico. Malathion, chlorpyrifos, deltamethrin, cypermethrin, 4,4-DDE, 4,4-DDD and 4,4-DDT were analyzed in 135 samples. Grain samples were not mutagenic and most pesticide levels were within regulation limits.

Subgingival microbiota of chronic periodontitis subjects from different geographic locations.

BACKGROUND: Most clinical studies assume that the subgingival microbiota is similar from one geographic location to another. The purpose of the present investigation was to examine the composition of the subgingival microbiota in chronic periodontitis subjects from four countries. METHOD: Subjects with chronic periodontitis (N, Sweden=101; USA=115; Brazil=58; Chile=26) were recruited. Subjects were measured at baseline for plaque, gingivitis, bleeding on probing (BOP), suppuration, pocket depth (PD) and attachment level (AL) at six sites per tooth. Subgingival plaque samples taken from the mesial aspect of each tooth at baseline were individually analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization (total samples=6036). % DNA probe counts comprised by each species was determined for each site and averaged across sites in each subject. Significance of differences in proportions of each species among countries was determined using ancova adjusting for age, mean pocket depth, gender and smoking status. p-Values were adjusted for multiple comparisons. RESULTS: On average, all species were detected in samples from subjects in the four countries. Thirteen species differed significantly in adjusted mean proportions among countries even after adjusting for multiple comparisons. Porphyromonas gingivalis, one species that differed in proportions among countries, comprised adjusted means of 7.5, 11.9, 1.6 and 6.6% of the microbiota in subjects from Brazil, Chile, Sweden and USA (p<0.001), while mean proportions of Treponema denticola were 6.7, 4.2, 0.8 and 2.3, respectively (p<0.001). In contrast, a key periodontal pathogen, Tannerella forsythensis, exhibited mean proportions ranging from 6.2-8.5% and did not differ significantly among countries. Besides these species, prominent species in Brazil were Actinomyces naeslundii genospecies 1 and 2 (8.4%, 7.2%) and Prevotella intermedia (6.5%); in Chile, Prevotella melaninogenica (6.4%) and Neisseria mucosa (5.3%); in Sweden A. naeslundii genospecies 2 (8.4%), Capnocytophaga gingivalis (7.1%) and Peptostreptococcus micros (5.0%); in USA A. naeslundii genospecies 2 (7.5%), P. intermedia (6.8%) and C. gingivalis (6.1%). CONCLUSIONS: The microbial profiles of subgingival plaque samples from chronic periodontitis subjects in four countries showed surprisingly marked differences. These differences persisted after adjusting for age, mean pocket depth, gender and smoking status.

Higher risk of preterm birth and low birth weight in women with periodontal disease.

Pregnant women with periodontal disease (PD) may be at increased risk for having preterm low-birth-weight (PLBW) children. We investigated whether the maintenance of the mothers' periodontal health after 28 weeks' gestation reduces the risk of PLBW. Of the 639 women studied, 406 had gingivitis and received treatment before 28 weeks' gestation, and 233 had PD and were treated after delivery. Data about previous and current pregnancies and known risk factors were obtained from patients' medical records. Primary outcomes were delivery before 37 weeks' gestation or an infant with birth weight below 2500 g. The incidence of PLBW was 2.5% in periodontally healthy women, and 8.6% in women with PD (p = 0.0004, relative risk = 3.5, 95% CI, 1.7 to 7.3). Risk factors significantly associated with PLBW were previous PLBW, PD, fewer than 6 pre-natal visits, and low maternal weight gain. PD was associated with both preterm birth and low birth weight, independent of other risk factors.

Occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in progressive adult periodontitis.

BACKGROUND: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia are the major periodontal bacteria species in most forms of progressive periodontitis in Scandinavia and the United States. The occurrence of periodontal pathogens appears to be different in subjects of different ethnic origin, and geographical factors may influence the distribution of these species. METHODS: The occurrence of A. actinomycetemcomitans, P. gingivalis, and P. intermedia was determined using a DNA probe in progressive adult periodontitis in Chileans. Sixty patients (mean age 43.6 +/- 8 years) who had not previously received any type of periodontal therapy were selected. Bleeding on probing, probing depth, and clinical attachment level measurements were made with an automated probe. Patients were monitored at 2-month intervals until at least 2 sites exhibited > or =2 mm attachment loss. Two subgingival plaque samples from active sites were taken in 56 subjects and matched with 2 plaque samples from inactive sites in the same individuals. RESULTS: P. gingivalis was found in 75% of active sites and in 59.7% of inactive sites in 96% of the patients (P = 0.022). P. gingivalis at high levels of detection was significantly more frequent in active sites (48.2%) than in inactive sites (31.2%) (P = 0.014). A. actinomycetemcomitans was detected in 6.25% of active sites and in 12.5% of inactive sites in 11.6% of patients. P. intermedia was found in 33% of patients and at a significantly higher proportion in active sites (49.1%) than in inactive sites (30.3%) (P = 0.006). There was a significantly higher proportion of inactive sites (34.8%) than active sites (19.6%) without any of the 3 pathogens (P = 0.016). Bleeding on probing was significantly more associated with active sites with high levels of P. gingivalis and with active sites with P. intermedia than with inactive sites. CONCLUSIONS: A high prevalence of P. gingivalis and P. intermedia was found in adult periodontitis, and the occurrence of these bacteria appears to be higher in Chileans than in other populations. No apparent association exists between A. actinomycetemcomitans and progressive adult periodontitis in Chileans.

Repeated metronidazole and amoxicillin treatment of periodontitis. A follow-up study.

BACKGROUND: The prevailing concept is that little or no clear benefit is derived from antibiotic therapy in chronic periodontitis. Studies to determine the effect of metronidazole plus amoxicillin (M+A) on adult periodontitis are questionable because standard design for clinical trials was usually not used. In addition, there is no information about the effect of M+A as the sole therapy for periodontitis. METHODS: A randomized, triple-blind, controlled clinical trial was used to determine the effect of systemic administration of M+A, as the sole therapy, in progressive adult periodontitis. Forty-six subjects with moderate to advanced adult periodontitis who showed > or =2 mm attachment loss in at least 2 sites in the previous 2 months were entered in the study. Subjects were randomly distributed to a group who received 21 tablets of metronidazole 250 mg plus amoxicillin 500 mg, or to a group receiving a placebo (1 tablet every 8 hours for 1 week). Patients were examined every 2 months for 12 months. The M+A or placebo regimen was repeated at 4 and 8 months. No effort was made to change the oral habits of patients and they received no additional therapy. Differences between groups were assessed using the Mann-Whitney U test. The differences at every 2-month interval within each group were assessed using the ANOVA test. RESULTS: Seven subjects abandoned the study; at 12 months the M+A group had 20 subjects and the placebo group 19. There were no significant differences in the clinical parameters at baseline between the 2 groups. After 2 months and thereafter, the M+A group showed significant clinical improvement while the placebo group showed a progressive deterioration of periodontal status. At 12 months compared to baseline, subjects of the M+A group showed: 1) a significant overall mean attachment gain of 0.43 mm (P = 0.005); 2) a significant decrease of active sites (P< or =0.03); 3) a significant increase of sites gaining attachment level (P< or =0.01); 4) a significant reduction of pocket depth (P< or =0.00006); and 5) a significant decrease in percentage of bleeding on probing sites (BOP) (P< or =0.0005). Significant differences between both groups at all 2-month evaluations were found in overall mean attachment level (P < or =0.000004), in percent of active sites (P< or =0.03), and in percent of BOP sites (P< or =0.02). Sites exhibiting > or =2 mm of attachment loss in 2 successive or alternate evaluations, and periodontal abscess were noticed only in the placebo group. CONCLUSIONS: A 1-week course of systemic M+A every 4 months, as the only therapy, arrests the progression of adult periodontitis and significantly improves the clinical parameters of the disease.

Effects of metronidazole plus amoxicillin in progressive untreated adult periodontitis: results of a single 1-week course after 2 and 4 months.

A randomized, double-blind, clinical study was done to assess the microbiological and clinical effects of metronidazole plus amoxicillin (M+A) as the only therapy in 46 patients with moderate to advanced progressive adult periodontitis. Patients were included in the study after at least 2 sites showed > or =2 mm clinical attachment loss. Bleeding on probing, probing depth, and clinical attachment level were measured using on automated probe. The percentage of surfaces with plaque was recorded at day 0, and at 2 and 4 months after therapy. No effort was made to change the oral hygiene habits of patients. Identification of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia was assessed utilizing DNA technology at day 0 and 2 months after therapy. Twenty-three patients received metronidazole 250 mg plus amoxicillin 500 mg, 3 times/day for a week and 23 a placebo. Two patients in the placebo group were dropped at 2 months because they had taken antibiotics for medical reasons. Statistical analyses of differences between groups was done using the Mann-Whitney test, and the differences within each group were tested with ANOVA. There were no significant changes in surfaces with plaque in either group after therapy. The percentage of bleeding sites decreased significantly from baseline to 2 and 4 months in the M+A group (P = 0.001), and increased in the placebo group. Differences in bleeding on probing between groups were significant at 2 (P = 0.018), and 4 months (P = 0.005). The mean attachment level values at 2 and 4 months post-therapy improved significantly in the M+A group compared to the placebo group (P = 0.001). Treatment with M+A resulted in a significant mean reduction in probing depth at 2 and 4 months compared to baseline values (P = 0.001). The M+A group showed a significant reduction of sites with high levels of Pg (P = 0.001) at 2 months compared with baseline values, and there was a significant reduction of sites with Pg and Pi in the M+A group compared with the placebo group. The results showed that a combined M+A treatment as the only therapy changes the proportion of some subgingival microorganisms and allows a significant improvement in clinical conditions.

Periodontal conditions and treatment needs, by CPITN, in the 35-44 and 65-74 year-old population in Santiago, Chile.

A CPITN survey involving Chileans aged 35-44 and 65-74 was conducted. A random, stratified sample by age, gender, socio-economic status and educational level was obtained, comprising 1150 individuals. Prevalence of chronic inflammatory periodontal disease (Codes 3 + 4) was 90.89 per cent in subjects aged 35-44, and 100 per cent in subjects aged 65-74. The total prevalence for both age cohorts was 92.19 per cent. Prevalence of periodontal disease was slightly lower in females but severity was significantly higher in males. A significant association between socio-economic status and periodontal health was found. Prevalence (Code 3 + 4) was 56.44 per cent in subjects of high, 98 per cent in subjects of middle, and 100 per cent in subjects of low socio-economic status. Also, the mean number of sextants with pockets > 6 mm (1.12) and mean number of excluded sextants (1.43) were significantly higher in subjects of low socio-economic status. An association between educational level and periodontal health was apparent. The only subjects who were periodontally healthy were in the group with university education. Prevalence of CITN (Code 3 + 4) was also significantly lower in subjects with university education. There was also a significant association between educational level and loss of teeth. Concerning missing teeth, 22 per cent were lost due to periodontal disease and 77 per cent due to caries. The prevalence of periodontal disease found in this adult representative Chilean population indicates that the entire population needs oral hygiene instruction and scaling, and that 45.70 per cent need complex periodontal treatment.

Racial tropism of a highly toxic clone of Actinobacillus actinomycetemcomitans associated with juvenile periodontitis.

Actinobacillus actinomycetemcomitans strains with enhanced levels of production of leukotoxin are characterized by a 530-bp deletion from the promoter region of the leukotoxin gene operon. Previous isolates with this deletion constituted a single clone belonging to serotype b, although they displayed minor differences among each other. We have analyzed the geographic dissemination of this clone by examining 326 A. actinomycetemcomitans isolates from healthy and periodontally diseased individuals as well as from patients with different types of extraoral infections originating from countries worldwide. A total of 38 isolates, all belonging to the same clone, showed the 530-bp deletion. Comparison of a 440-bp sequence from the promoter region of the leukotoxin gene operon from 10 of these strains revealed complete identity, which indicates that the deletion originates from a single mutational event. This particular clone was exclusively associated with localized juvenile periodontitis (LJP). In at least 12 of 28 families from which the clone was isolated, more than one family member had LJP. Notably, all the subjects carrying this clone had a genetic affiliation with the African population. These observations suggest that juvenile periodontitis in some adolescents with an African origin is associated with a disseminating clone of A. actinomycetemcomitans.

Periodontal conditions in 15-19-year-old Chileans.

A CPITN survey involving Chilean high school students aged 15-19 years was conducted. A random stratified sample by age, sex and socio-economic status was obtained, and comprised 2400 subjects. The total prevalence of periodontal disease (Code 3+4) was 10.49 per cent. There was a significant difference in the prevalence of periodontal disease in males (9 per cent) compared to females (12.16 per cent). The prevalence of periodontal disease was higher in students of low socio-economic status (15.87 per cent) than in students of middle (9.22 per cent) and high socio-economic status (8.93 per cent). The periodontal treatment needs were also higher for students of low socio-economic status than for students of the highest family income. The prevalence of periodontal disease and treatment needs found in Chilean students showed that virtually this entire population needs oral hygiene instruction, that 70 per cent need scaling, and that 10.49 per cent need complex periodontal treatment.

Occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in juvenile periodontitis.

The occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in subgingival plaque in 24 juvenile periodontitis patients was determined using DNA probe. 36 samples of subgingival plaque from 36 pockets having > or = 6 mm depth, > or = 3 mm of loss of attachment, and bleeding on probing and/or suppuration were taken from 18 patients with localized juvenile periodontitis (LJP, age range 12-24 years); and 12 samples from 6 patients with generalized juvenile periodontitis (GJP, age range 23-26 years). As control, an equal numbers of samples from healthy sites in the same patients were studied. P. gingivalis was found in 17 of 18 LJP patients, and in 31 of 36 diseased sites in those patients. P. intermedia was found in 15 out of the 18 LJP patients and in 28 of the 36 diseased sites. A. actinomycetemcomitans was present in 7 of the 18 LJP patients, and in 9 of the 36 diseased sites, and was not found in any GJP patients. All GJP patients had P. gingivalis (11 out of 12 diseased sites) and P. intermedia (all of the diseased sites). None of the three bacterial species was detected in healthy sites of GJP patients, and were found in healthy sites in only 2 of 18 LJP patients. The high prevalence and high levels of P. gingivalis and P. intermedia found in the LJP and GJP patients studied, suggest that there are populations affected by juvenile periodontitis in which this type of periodontitis is more associated with these species than with A. actinomycetemcomitans.

Occurrence of certain bacterial species and morphotypes in juvenile periodontitis in Chile.

The occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Eikenella corrodens, Fusobacterium nucleatum, Campylobacter rectus, Capnocytophaga species, and certain bacterial morphotypes was determined in 18 affected and 18 unaffected sites in 10 localized juvenile periodontitis (LJP) patients, and in 10 affected and 10 unaffected sites in 5 generalized juvenile periodontitis (GJP) patients. The subgingival proportion of the 7 bacterial species was determined by selective and nonselective culturing. The results showed that when considering the pure prevalence of bacteria ( > 0%) there were significant differences (P < 0.05) in the subgingival plaque microflora of the affected sites versus those of the unaffected sites for P. gingivalis, A. actinomycetemcomitans, P. intermedia, E. corrodens, C. rectus, and F. nucleatum in LJP, and for P. gingivalis, P. intermedia, and F. nucleatum in GJP. The mean proportions of cocci, motile rods and spirochetes were also significantly different (P < 0.05) in affected sites compared to unaffected sites. Capnocytophaga sp, F. nucleatum, P. intermedia, and E. corrodens were found in more than 75% of affected sites in LJP. When taking the approach that an organism, to be associated with periodontal disease, has to be detected above a certain minimum threshold, the results indicated that bacteria most frequently associated with LJP and GJP in Chile are P. gingivalis (66% of LJP and 80% of GJP affected sites), and A. actinomycetemcomitans (44% of LJP and 50% in GJP affected sites). Different bacterial species may be judged to be important in the disease process depending upon whether a pure bacterial prevalence, or a prevalence above a certain detection level, is considered.

No association between secretor status of ABO blood group antigens and juvenile periodontitis.

The aim of this study was to determine the association between secretor status of ABO blood group antigens and localized juvenile periodontitis (LJP). Forty-three patients with LJP (mean age 20.8 years) diagnosed according to Baer's criteria were selected. Thirty two periodontally healthy normal subjects (mean age 24.7 years) were use as control. Samples of blood and saliva were collected from patients and from control subjects. ABO blood group was determined by agglutination of erythrocytes with appropriate antisera. Determination of soluble ABO antigens in saliva was made by the haemagglutination inhibition assay. Subjects with O blood group were most frequent in both groups. The distribution of blood groups, and secretor and non-secretor status of ABO group antigens in LJP patients and control subjects was not significant. The results provide support for the hypothesis that there is no association between non-secretor status and LJP.

No association between secretor status of ABO blood group antigens and juvenile periodontitis

The aim of this study was to determine the association between secretor status of ABO blood group antigens and localized juvenile periodontitis (LJP). Forty-three patients with LJP (mean age 20.8 years) diagnosed according to Baer’s criteria were selected. Thirty two periodontally healthy normal subjects (mean age 24.7 years) were use as control. Samples of blood and saliva were collected from patients and from control subjects. ABO blood group was determined by agglutination of erythrocytes with appropriate antisera. Determination of soluble ABO antigens in saliva was made by the haemagglutination inhibition assay. Subjects with O blood group were most frequent in both groups. The distribution of blood groups, and secretor and non-secretor status of ABO group antigens in LJP patients and control subjects was not significant. The results provide support for the hypothesis that there is no association between non-secretor status and LJP.

No association between secretor status of ABO blood group antigens and juvenile periodontitis.

The aim of this study was to determine the association between secretor status of ABO blood group antigens and localized juvenile periodontitis (LJP). Forty-three patients with LJP (mean age 20.8 years) diagnosed according to Baers criteria were selected. Thirty two periodontally healthy normal subjects (mean age 24.7 years) were use as control. Samples of blood and saliva were collected from patients and from control subjects. ABO blood group was determined by agglutination of erythrocytes with appropriate antisera. Determination of soluble ABO antigens in saliva was made by the haemagglutination inhibition assay. Subjects with O blood group were most frequent in both groups. The distribution of blood groups, and secretor and non-secretor status of ABO group antigens in LJP patients and control subjects was not significant. The results provide support for the hypothesis that there is no association between non-secretor status and LJP.

Clinical, laboratory, and immunological studies of a family with a high prevalence of generalized prepubertal and juvenile periodontitis.

A study of a consanguineous family with a high prevalence of localized juvenile periodontitis (LJP) and generalized prepubertal periodontitis (GPP) was done over a 7-and-a-half year period. The parents had adult periodontitis, while 2 daughters, aged 13 and 15, had LJP. Furthermore, 2 other daughters, ages 14 and 10, and a son, aged 9, were affected by GPP. Two remaining siblings were not affected. Clinical and radiographic examinations on all family members were done, and chemotaxis for blood neutrophils was assessed. Laboratory tests, immunological examinations, and evaluation for neutrophil functions were done on the GPP patients. Microbiological cultures were performed on 2 of the GPP patients, as well as in the mother. The mother, the 2 LJP patients, and 1 of the unaffected siblings had depressed PMN chemotaxis. The other family members, including the 3 GPP patients, had normal PMN chemotaxis. GPP patients did not have any systemic disease, and evidence of major defects in the immunological functions was not detected. LJP patients were successfully treated with root planing, subgingival curettage, and tetracycline therapy. Intensive periodontal therapy, combined with systemic administration of antibiotics, was not effective in halting periodontal tissue destruction in the 3 GPP patients. Results indicate that the underlying cause of GPP is not always related to leukocyte dysfunction. Since Actinobacillus actinomycetemcomitans was the most frequent pathogen found in subgingival microflora of 2 of the GPP patients, it is assumed that it may play a key role in the etiology of GPP.

Prevalence of juvenile periodontitis in Chile.

The aim of this survey was to study the prevalence of juvenile periodontitis in schoolchildren aged 15-19 years in Santiago, Chile. A random sample of 2500 schoolchildren (1318 male, 1182 female) that represented the full range of different socio-economic strata and ethnic groups seen in the population of Santiago, was used. Initially, the children were screened clinically at school by assessment of probing depths around the incisors and first molars with a WHO 621 pattern probe. Children with 2 or more teeth with 5.5 mm or deeper pockets were invited for a radiographic examination comprising bitewing radiographs of molars, and periapical radiographs of incisors. Any subject with 2 mm or more alveolar bone loss was invited for a full clinical and radiographic examination. After screening, 27 subjects had a tentative diagnosis of juvenile periodontitis. 4 of these refused radiographic examination and only accepted a thorough clinical examination. 23 subjects presented themselves for the radiographic and complete clinical examination. Of the 27 subjects selected for detailed examination, 8 subjects (7 female, and 1 male) were diagnosed as having juvenile periodontitis. There was an overall prevalence of juvenile periodontitis of 0.32% with 95% confidence, which gives a range of +/- 0.10%. When prevalence was assessed by socio-economic status, juvenile periodontitis was found more commonly in low socio-economic group. The results of the current study suggest that in Chile, there might be a relationship between socio-economic status and prevalence of juvenile periodontitis, and that this disease is more frequent in women.

Histological differences between teeth with adult periodontitis and prepubertal periodontitis.

Thirty-nine permanent teeth from three siblings aged 11 to 14 years were extracted because of generalized prepubertal periodontitis (PP) and studied histologically with light microscopy. Twenty healthy teeth (HT) removed for orthodontic procedures from 10 children of similar ages and 22 teeth affected by adult periodontitis (AP) extracted from patients over 50 years old were used as controls. The cementum of the PP teeth was much thicker than that of the healthy teeth. A high percentage of resorption, unrelated to inflammation, was found in all the teeth studied. In 24 PP teeth the cementum was infiltrated by microorganisms and bacterial substances. All PP teeth showed a cuticle ranging from 10 to 80 microns in thickness on the diseased cementum. No similar structure was noted on the diseased cementum of the AP teeth. The PP teeth did not show any structural changes which could account for the severity of the periodontal lesions.

Morphologic and histochemical characteristics of the dental cuticle in teeth affected by prepubertal periodontitis.

A study was undertaken to determine the nature and composition of the cuticle found in teeth with generalized prepubertal periodontitis (PP). This was accomplished by using histological and histochemical methods on decalcified specimens. Forty-six permanent teeth which were extracted from three prepubertal periodontitis patients (siblings) were used. Nineteen of the 46 teeth were obtained with the facial or interdental gingiva. As a control, 20 healthy teeth extracted from 10 children for orthodontics reasons, and 22 teeth affected by terminal adult periodontitis (AP), were used. All the teeth with PP showed a thick coat covering the root surface from the cemento-enamel junction to the junctional epithelium. In some teeth the cuticle extended a few microns coronally to the cemento-enamel junction. The cuticle had a thickness which varied between 10 to 80 microns. It usually presented a very regular surface in the coronal portion of the root, and showed laminations suggesting appositional growth. In the middle and apical portions of the root exposed to the pocket, the cuticle was lobular with a very irregular surface and was covered with a thick microbial plaque. The staining reactions indicated that the cuticle was made of proteins probably derived from the inflammatory exudate. None of the healthy teeth examined nor those affected by AP showed a cuticle similar to those with PP. The cuticle formed on the teeth with PP appears to be an abnormal structure of proteinaceous nature, characteristic of these teeth, and may possibly play a role in the pathogenesis of the disease.