Virulence of Streptococcus mutans: An intrafamilial cohort study on transmission of genotypes.

BACKGROUND: The main aims of this cohort study were to measure the intrafamilial risk of transmission, sharing and stability of the most virulent S. mutans genotypes. MATERIAL AND METHODS: A total of 392 clinical isolates of S. mutans obtained from caries-active adults and genotyped to evaluate their transmissibility over time. After extraction of the chromosomal DNA, PCR were performed to detect the genes involved in the production of GbpA (gbpA) and mutacin types I, II, III and IV (mutAI, mutAII, mutAIII and mutAIV). RESULTS: The gbpA, mutAI, mutAII, mutAIII and mutAIV genes were detected in 77.3, 12.5, 51, 16.6 and 89.8% of S. mutans isolates, respectively. The virulence of S. mutans was associated with its transmission (P< 0.01) and stability (P = 0.01), with the most virulent genotypes having higher transmissibility (RR = 1.83, 95% CI 1.44 to 2.32) and higher stability in the oral cavity (RR = 1.52, 95% CI 1.06 to 2.19). CONCLUSIONS: Genotypes with the genetic information to synthesize GbpA and mutacins present an important ecological advantage in the process of colonization by S. mutans; they remain stable among the oral microbiota of the host and favor intrafamilial transmission. Key words:Streptococcus mutans, virulence factors, transmission, dental caries.

Pit and Fissure Sealants with Different Materials: Resin Based x Glass Ionomer Cement ­ Results after Six Months

Objective: To compare the retention and superficial characteristics between a new resin-modified glass ionomer sealant and resin sealant. In addition, the teeth sealed were compared to partially erupted first molars (control group) without sealing in relation to the incidence of dental caries. Material and Methods: Initially, 31 children aged 6-8 years participated in this study. The study children showed caries history, but had at least two healthy first molars. A total of 114 teeth were randomly divided into three groups: Clinpro (n=36), Fluroshield (n=38), and control (n=40). The two sealants were applied under relative isolation after previous prophylaxis and enamel etching with phosphoric acid 35% (15s). Clinical evaluation was performed by two calibrated examiners. They evaluated the retention and surface characteristics of the occlusal surface. Results: Fluroshield® showed significantly greater retention than ClinproTM Varnish® XT (p=0.002). However, the performance analysis of the success and failure of retention presented no significant difference between the materials (p=0.141). Concerning to the surface characteristics, Fluroshield performed better than Clinpro after analyzing the marginal deterioration, marginal discoloration, and superficial discoloration (p<0.05). The surface texture of the materials under study was similar (p=0.071). Sealed groups (Clinpro=Fluroshield) showed similar performance in the prevention of dental caries, which was significantly lower than that of control group (p=0.001). Conclusion: Both sealants, Fluroshield® and Clinpro TM Varnish® XT were effective in preventing caries lesion within 6 months, although Fluroshield sealant showed better clinical retention.

A Two-Year Clinical Evaluation of Fluoride and Non-Fluoride Resin-Based Pit-and-Fissure Sealants.

The aim of this study was to evaluate and compare for 24 months, the retention and surface characteristics of two pit-and-fissure sealants: Helioseal Clear and Helioseal F (Ivoclar Vivadent). The correlation between the different stages of eruption and sealant retention was also verified. Fifty children aged 6 to 8 years participated in the study, totalizing 153 teeth divided into two groups: HC (Helioseal Clear) and HF (Helioseal F). After 6, 12, 18 and 24 months, a clinical examination was performed by previously calibrated examiners. The surface characteristics and the retention of the sealants (modified RYGE & SNYDER criteria) were assessed. Analyzing the occlusal surface, HC exhibited a statistically significant higher retention at 12 (p=0.0345) and 24 months (p=0.0076). Concerning the surface characteristics, only the superficial discoloration of HC was smaller than HF, during the entire studied period. For all the other characteristics, the results of the Mann-Whitney test were highly significant at different periods (p=0.0000 to 0.0421). The frequency of air bubbles within the sealant surfaces, determined by Chi-square test, was significantly higher in HF (p=0.000:12 and 18 months to p=0.002: 6 and 24 months). HC sealant material exhibited the best performance regarding the retention and surface characteristics on the occlusal surface.

Management of a permanent tooth after trauma to deciduous predecessor: an evaluation by cone-beam computed tomography.

Impaction of permanent teeth represents a clinical challenge with regard to diagnosis, treatment plan, and prognosis. There is a close relationship between deciduous teeth and permanent teeth germ, and any injury in the deciduous dentition may influence the permanent teeth eruption. The extent of the damage caused to the permanent teeth germ depends on the patient age at the time of injury, type of trauma, severity, and direction of the impact. Conventional radiographic images are frequently used for diagnosis; however, recent developments in three-dimensional (3D) imaging systems have enabled dentistry to visualize structural changes effectively, with better contrast and more details, close to the reality. The cone-beam computed tomography (CBCT) has been used in the diagnosis and treatment plan of these impacted teeth. The purpose of the present case report is to describe a successful conservative management of a retained permanent maxillary lateral incisor with delayed root development after a trauma through the deciduous predecessor in a 9 year-old patient. After clinical and radiographic examination, a CBCT examination of the maxilla was requested to complement the diagnosis, providing an accurate 3D position of the retained tooth and its relationship to adjacent structures. The proposed treatment plan was the surgical exposure and orthodontic traction of the retained tooth. The lateral incisor spontaneously erupted after 6 months. Therefore, this case report suggests that permanent teeth with incomplete root formation have a great potential for spontaneous eruption because no tooth malposition or mechanical obstacles are observed.

Dental erosion in a group of 12- and 16-year-old Brazilian schoolchildren.

PURPOSE: This study's purpose was to assess the prevalence of dental erosion in adolescents and to investigate the association between erosion and sociodemographic characteristics. METHODS: This study consisted of a single center cluster random sample of 414 adolescents (12 and 16 years old) of both genders from private and public schools in Bauru, São Paulo, Brazil. Two previously calibrated examiners (kappa=0.85) used the O'Brien (1994) index for assessment of dental erosion on the buccal and palatal surfaces of the permanent maxillary incisors and on the occlusal surfaces of the permanent first molars. Data on gender, type of school, and mean family income were collected by a questionnaire completed by the adolescents. Descriptive statistics were applied to the data, and the associations between erosion and sociodemographic variables were investigated by chi-square test (P<0.05). RESULTS: The prevalence of dental erosion was 20% (N=83), with only enamel being involved (score 1). The labial surface was the most affected (16%). There were no significant differences between the presence of erosion and gender, type of school, and mean family income. CONCLUSIONS: The results indicate that dental erosion restricted to enamel was observed among adolescents in Bauru/Brazil, and there was no correlation between this condition and sociodemographic factors.

In vitro evaluation of enamel erosion after Nd:YAG laser irradiation and fluoride application.

OBJECTIVE: Previous investigations have demonstrated improved enamel demineralization resistance after laser irradiation. Due to the possibility of a synergistic effect between laser and fluoride, this study investigated the effect of fluoridated agents and Nd:YAG irradiation separately and in combination on enamel resistance to erosion. METHODS: One hundred bovine enamel blocks were randomly divided into 10 groups: G1, untreated (control); G2, acidic phosphate fluoride (APF) (1.23% F) for 4 min; G3, fluoride varnish for 6 h (NaF, 2.26%); G4, 0.5 W Nd:YAG laser (250 microm pulse width, 10 Hz, 35 J/cm(2), with uniform velocity for 30 sec in each application); G5, 0.75 W Nd:YAG laser (52.5 J/cm(2)); G6, 1.0 W Nd:YAG laser (70 J/cm(2)); G7, APF + 0.75 W Nd:YAG laser; G8, 0.75 W Nd:YAG laser + APF; G9, fluoride varnish + 0.75 W Nd:YAG laser; and G10, 0.75 W Nd:YAG laser + fluoride varnish. During 10 d the erosive cycle was conducted by immersion of the blocks in Sprite light((R)) for 1 min, followed by immersion in artificial saliva for 59 min. This procedure was consecutively repeated four times per day. In each day, during the remaining 20 h, the blocks were maintained in artificial saliva. The wear was evaluated by profilometry (days 5 and 10). Data were tested by two-way ANOVA and Bonferroni's tests (p < 0.05). RESULTS: The mean wear at days 5 and 10 was, respectively: G1, 1.83 and 2.67 microm; G2, 1.04 and 2.60 microm; G3, 1.03 and 2.48 microm; G4, 1.13 and 2.47 microm; G5, 1.07 and 2.44 microm; G6, 1.0 and 2.35 microm; G7, 0.75 and 2.27 microm; G8, 0.80 and 2.12 microm; G9, 0.76 and 2.47 microm; and G10, 1.09 and 2.46 microm. At day 5, all the experimental groups presented significant lesser wear when compared to control group. However, at 10 d, only G7 and G8 were still different from control. CONCLUSIONS: The association between APF application and laser irradiation seems to be an alternative preventive measure against dental erosion.

Effect of Nd:YAG irradiation and fluoride application on dentine resistance to erosion in vitro.

OBJECTIVE: In this paper we evaluated the effect of two fluoridated agents and Nd:YAG irradiation separately and in combination on dentine resistance to erosion. BACKGROUND DATA: The morphological changes in dentin induced by laser treatment may reduce the progression of erosive lesions. Due to the possibility of a synergistic effect of laser with fluoride, this study was conducted. MATERIALS AND METHODS: Eighty bovine dentine samples (4 x 4 mm) were randomly divided into eight groups, according to the following treatments: G1: untreated (control); G2: acidic phosphate fluoride gel (APF 1.23%) for 4 min; G3: fluoride varnish (NaF 2.26%) for 6 h; G4: 0.5 W Nd:YAG laser (250 microsec pulse, 10 Hz, 35 J/cm2, 30 sec); G5: 0.75 W Nd:YAG laser (52.5 J/cm2); G6: 1.0 W Nd:YAG laser (70 J/cm2); G7: APF + 0.75 W Nd:YAG laser; and G8: NaF + 0.75 W Nd:YAG laser. After the treatments, half of each dentine surface was protected with nail varnish. The samples were stored in artificial saliva (30 mL/sample) for 24 h and submitted to four erosive 1-min cycles. Between the erosive attacks, the blocks were maintained in artificial saliva for 59 min. The erosive wear was evaluated by profilometry. RESULTS: The mean wear (+/-SD, microm) was: G1: 1.20 +/- 0.20; G2: 0.47 +/- 0.06; G3: 0.81 +/- 0.11; G4: 1.47 +/- 0.32; G5: 1.52 +/- 0.24; G6: 1.49 +/- 0.30; G7: 0.49 +/- 0.11; and G8: 1.06 +/- 0.31 (Tukey's test, p< 0.05). CONCLUSIONS: Laser irradiation was not able to reduce dentine erosion. However, fluoride application was able to increase the dentine's resistance to erosion, and APF showed better results than fluoride varnish.

Resin-modified glass ionomer cement and a resin-based material as occlusal sealants: a longitudinal clinical performance.

PURPOSE: The aim of this study was to compare retention, effectiveness in caries prevention and superficial characteristics in 2 different materials used as an occlusal sealant. METHODS: The sample consisted of 108 school children with a mean age of 7.5+/-1.25 years, in which 364 first permanent molars were divided into 6 groups: (1) group 1=Delton + rubber dam (used only for this group); (2) group 2=Delton + cotton rolls; (3) group 3=Prime & Bond 2.1 + Delton; (4) group 4=Vitremer with a 0.25:1 powder/liquid proportion; (5) group 5=Primer + Vitremer with a 0.25:1 powder/liquid proportion; and (6) group 6=Vitremer with a 1:1 powder/liquid proportion. RESULTS: After 12 months, the total retention rate for groups 6, 1, 2, 3, 4, and 5 was, respectively: 92%, 79%, 67%, 52%, 41% and 12%. For the 3 occlusal areas, retention was: 97%, 92%, 86%, 77%, 69%, and 36%. For the modified criterion, the proportion test showed a statistically significant difference (P<.05) between: groups 1 and 4; groups 6 and 2; and group 3, 4, and 5 with all others groups. Considering the total of 3 areas, there was a statistically significant difference (P<.05) between: groups 1 and 6 with groups 3 and 4; group 2 with group 4; and groups 6 and 5 with the others. CONCLUSION: The resin-modified glass ionomer cement may be a promising alternative as an occlusal sealant.

[[Streptococcus mutans Acquisition and Dental Caries Development in First-Born Children].] / Aquisição de Estreptococos Mutans e Desenvolvimento de Cárie Dental em Primogênitos.

OBJECTIVE: To evaluate the moment of streptococcus mutans (SM) acquisition, caries development and their associate variables along 23 months, in first-born children of low socioeconomic status families, starting at 7 months of age. METHOD: The sample was chosen based on highly SM-colonized mothers, including all members of 14 families living in the same houses. The study included 14 mothers, 14 fathers and 14 first-borns and 8 relatives (mostly grandparents). Initial clinical examinations and radiographs determined the caries indices and periodontal conditions of the adults. SM count in all adults was made in the first 2 visits. The children were examined for SM count, number of teeth and number of carious lesions, in 4 visits. RESULTS: SM prevalence was high in the adults, being absent in only one of the parents. SM was found in 1, 2, 3 and 10 children in the first, second, third and fourth visits. Dental caries was detected in only 3 children in the last visit (at 30 months), who presented significantly higher SM scores than the children without caries in the same visit. CONCLUSION: A low income social condition and mothers highly colonized by SM do not mean necessarily early SM colonization and high caries activity in children with oral homecare. Caries development is significantly associated with high SM scores in the children.

Influence of toothbrushing on enamel softening and abrasive wear of eroded bovine enamel: an in situ study.

This study assessed the surface softening and abrasive wear of eroded bovine enamel with or without the influence of toothbrushing. Five volunteers took part in this in situ study of 5 days. They wore acrylic palatal appliances containing 6 bovine enamel blocks divided in two rows with 3 blocks, which corresponded to the studied groups: erosion without toothbrushing (GI) and erosion with toothbrushing (GII). The blocks were subjected to erosion by immersion of the appliances in a cola drink for 10 minutes, 4 times a day. After that, no treatment was performed in one row (GI), whereas the other row was brushed (GII). The appliance was then replaced into the mouth. Enamel alterations were determined using profilometry and microhardness tests. Data were tested using paired Students t test (p < 0.05). The mean wear values (microm) and percentage of superficial microhardness change (%SMHC) were respectively: GI--2.77 +/- 1.21/91.61 +/- 3.68 and GII--3.80 +/- 0.91/58.77 +/- 11.47. There was a significant difference in wear (p = 0.001) and %SMHC (p = 0.001) between the groups. It was concluded that the wear was more pronounced when associated to toothbrushing abrasion. However, toothbrushing promoted less %SMHC due to the removal of the altered superficial enamel layer.

Airpolishing effect on bovine enamel and the posterior remineralizing effect of saliva. An in vitro study.

PURPOSE: The aim of the present study was to evaluate the alterations of surface microhardness and wear caused by the sodium bicarbonate jet on bovine enamel and the further remineralizing effect of artificial saliva. METHODS: Fifteen enamel samples (4,0mm x 4,0mm) were used, which constituted the groups: no treatment (MI); treatment with sodium bicarbonate jet (MII and DI); treatment with sodium bicarbonate jet and immersion in saliva for one hour (MIII and DII), 24 hours (MIV and DIII) and 7 days (MV and DIV). Microhardness tests were carried out using a microdurometer in groups M and wear tests by a rugosimeter in groups D. The data were assessed by the one criterion variance analysis and Tukey test. RESULTS: The mean value of microhardness, in KHN, in groups MI, MII, MIII, MIV and MV were 359,80; 335,46; 369,20; 377,73 and 341,86, respectively, whereas the mean values in microm, of wear for group DI, DII, DIII and DIV were 0,564; 0,519; 0,441 and 0,428, respectively. CONCLUSIONS: The sodium bicarbonate jet caused a wear and a reduction in microhardness on the enamel surface; saliva promoted the recovery of initial condition surface microhardness and reduced the wear; the repairing effect of saliva on the surface microhardness alterations occurred within one hour of treatment, having no significant statistical difference from the effect obtained in 24 hours; the best saliva repairing effect on the wear occurred with treatment of 24 hours.

Evaluation of glass ionomer sealants placed according to the ART approach in a community with high caries experience: 1-year follow-up.

The aim of this study was to investigate the retention rates and effect on occlusal caries incidence of two glass ionomers used as sealants, placed according to the Atraumatic Restorative Treatment (ART) approach, in a high caries-risk community. A total of 150 newly erupted first molars of 42 schoolchildren, between 6-8 years of age were selected. The teeth were divided into two groups: experimental and control groups. In the experimental group, 76 teeth were sealed using Vidrion R-SS White (conventional GIC) and in the control group, 74 teeth were sealed using ChemFlex-Dentsply (high-viscosity conventional GIC). The sealants were applied by one operator following the "press finger technique", described in the ART-WHO manual. Two calibrated independent examiners carried out the evaluation according to the ART criteria. The intra and inter-examiner agreements were 0.84 and 0.81, respectively. Data were submitted to Mann-Whitney and Chi-square tests (p<0.05). At the 1-year follow-up, 136 (90.7%) sealants were evaluated. In the control group: 28 (41.8%) of the sealants were partially or completely retained, 38 (56.7%) completely lost, and 1 (1.5%) was replaced by another treatment. In the experimental group, 30 (43.5%) of the sealants were partially or completely retained, 38 (55.1%) were clinically scored as complete loss and 1 (1.4%) were replaced by another treatment. Seven sealants in both groups were not evaluated. Secondary caries was not observed in both groups. There was no statistically significant difference between the retention (p=0.49) and effect on caries incidence rates for both groups (p=0.84). The clinical performance of the glass ionomer sealants of both groups was considered satisfactory with a high success rate (98.5%). Although the sealants placed according to the ART approach showed retention rates lower than 50% after 1 year in newly erupted first molars, this approach seems to be appropriate for communities with high caries experience.

In vitro evaluation of the cariostatic action of esthetic restorative materials in bovine teeth under severe cariogenic challenge.

Considering that caries around restorations is a serious problem in dentistry, and some restorative materials with fluoride may be important in inhibiting these lesions, this research is aimed at performing an in vitro evaluation of the cariostatic action of some esthetic restorative materials. Standardized cavities were prepared in the center of either intact blocks of bovine enamel or with bovine teeth containing early artificial carious lesions. The specimens were restored with a high viscosity glass ionomer cement (Molar Ketac), a resin-modified glass ionomer cement (Vitremer), a polyacid-modified resin composite (Dyract AP) and a conventional resin composite (Z-250). In addition to the restored specimens, four corresponding control groups were evaluated. All groups, except for two control groups, were subjected to a demineralization/remineralization cycling model for 14 days, simulating a situation of severe cariogenic challenge. The blocks were then longitudinally sectioned through the restorations. Mineral loss was evaluated in these specimens using the Knoop microhardness profiles in longitudinal sections at three different distances of the cavities and at eight distinct depths in relation to the external enamel surface. Statistical analysis of the results showed significant differences (p < 0.05) among the groups, although none of the study materials completely inhibited creation of the lesions. Vitremer demonstrated the best cariostatic action in intact bovine enamel. Ketac Molar, in intact or demineralized enamel, and Vitremer, in demineralized enamel, presented intermediate cariostatic potential. Z-250 and Dyract AP did not demonstrate any cariostatic effect. The data suggests that glass ionomer cements demonstrated better cariostatic action compared to the other restorative materials.

Esthetic improvement following enamel microabrasion on fluorotic teeth: a case report.

Enamel microabrasion is a proven method of removing intrinsic and superficial defects from teeth, establishing esthetics with minimal loss of dental enamel. This article reports one case in which two different microabrasion techniques were used to remove fluorotic stains from teeth.

Periodontopathogens in the saliva and subgingival dental plaque of a group of mothers.

The aim of this study was to assess the periodontal condition and the presence of putative periodontal pathogens in 30 Brazilian mothers, aging 21-40 years (28.4 4.49 years), and in their children, aging 5-6 years, since mothers can be a source of pathogens and, thus, influence their children's bacteriological and clinical condition. Besides assessing the plaque index (PI), gingival index (GI) and pocket probing depth (PD), the survey analyzed four subgingival dental plaque samples from mothers and children, as well as a sample of stimulated saliva from mothers. Those samples were analyzed by means of the slot immunoblot (SIB) technique, in order to determine the presence of Actinobacillus actinomycetemcomitans (Aa), Prevotella nigrescens (Pn), Porphyromonas gingivalis (Pg) and Treponema denticola (Td). The mean values and standard deviations of the evaluated clinical variables for mothers and children were, respectively: 1.86 0.67 and 1.64 0.68 for PI, and 1.24 0.67 and 0.82 0.37, for GI. Only for mothers, the total PD was 1.81 0.69 mm, and the PD of four sites was 4.03 1.40 mm. The Wilcoxon test revealed significant difference (p < 0.05) between mothers and their children only as to GI. The most prevalent bacteria in mothers were, in decreasing order: Aa, Pn, Pg and Td. The children presented patterns of oral hygiene and bacterial profiles similar to those of their mothers, in spite of the fact that most of them did not present enough subgingival plaque for testing. The comparison between mothers' subgingival dental plaque and saliva samples revealed statistically significant differences (p < 0.05) for all bacteria, with greater positivity and scores in the saliva, which demonstrates that it is an indicator of oral colonization and can work as a vehicle for the transmission of periodontopathogens from mothers to their children.