Elimination of E. faecalis with NaOCl versus chlorhexidine gluconate from primary molar root canal systems: an ex vivo model study

OBJECTIVES

This ex vivo human study aimed to evaluate the efficacy of NaOCl and chlorhexidine gluconate (CHG) irrigations in eliminating Enterococcus faecalis from the RCS of primary molars.

MATERIALS AND METHODS

Disinfected extracted primary molars were inoculated with E. faecalis for 24 h. Then, the RCS samples were then irrigated with either 2.5% NaOCl, 0.2% and 2% CHG, or sham saline. The samples were collected immediately after irrigation; and 24 h later, the bacterial viability and counts were measured using blood agar and qRT-PCR, respectively. Histological sections were used to measure E. faecalis penetration and viability in dentin tubules using fluorescence microscopy.

RESULTS

The recovery of viable E. faecalis after the irrigation of the primary molars showed more significant bactericidal effects of NaOCl and 0.2% and 2% CHG than of saline. Immediately after the irrigation, the NaOCl group showed the greatest reduction in E. faecalis; and 24 h later, all the groups had lower viable E. faecalis than the saline control. The bacterial penetration was also lowest in the NaOCl group, although there was no difference in bacterial viability in the tubules between the groups.

CONCLUSION

In primary teeth, NaOCl and CHG showed similar degrees of bacterial elimination efficacy in terms of E.faecalis.

CLINICAL RELEVANCE

Within the limitations of this study, NaOCl and CHG have the similar ability to perform endodontic irrigation of primary ex vivo teeth regarding the elimination of E.faecalis, but NaOCl penetrates dentin tubules better.

Evaluation of antibacterial effects of different intracanal medicaments on Enterococcus faecalis in primary teeth: An in vitro study

OBJECTIVES

Successful endodontic therapy is based on the reduction of infecting bacteria by cleaning, shaping, and disinfecting of the root canal system, thus the use of intracanal dressing is necessary for optimal success of root canal treatment. This study was designed to evaluate the effect of chitosan and propolis as intracanal medicaments against Enterococcus faecalis compared to calcium hydroxide in primary root canals.

MATERIAL AND METHODS

Ninety-six extracted primary second molars were collected. Teeth preparation was completed to size 30 K-file. They were randomly divided into four groups; (A): chitosan, (B): propolis, (C): calcium hydroxide, and (D): control group (saline). The tooth specimens were inoculated with E. faecalis. Then, tested materials were applied for all groups in accordance to the groups each tooth belonged to. Following this, the bacterial colonies were counted after 24 h, 72 h, and 1 week of applying dressing materials and incubation. Finally, one-way analysis of variance and Fisher's least significant difference tests were used for statistical comparisons between the groups at a significance level of .05.

RESULTS

No statistically significant difference was found between groups A, B, and C for both 24 h and a week (p ≥ .05). Yet, a statistical difference between groups A, B, C, and D after 72 h and 1 week were seen (p ≤ .05).

CONCLUSIONS

Chitosan and propolis medicaments were as effective as calcium hydroxide against E. faecalis in primary root canal treatment and might be considered as an alternative dressing material between treatment sessions.

Evaluation of root canal cleaning efficacy of selfadjusting files, protaper rotary, and manual K-Files in primary teeth - An In vitro Comparative study

Background

The success of pulpectomy depends on complete eradication of microbial load by cleaning and shaping the primary root canals that is difficult to achieve because of anatomical intricacy of primary pulp dentin complex. Numerous instruments were tried, however, they proved to be inadequate. Selfadjusting file (SAF) is a newer file system that facilitates less dentin removal with maximal cleansing of root canals.

Aim

To evaluate and compare the in vitro root canal cleaning efficacy with SAF, Protaper Universal, and Hand K-files in primary teeth.

Materials and Methods

Sixty extracted primary anterior teeth were randomly divided into three groups by lottery method. Access cavity was prepared, the canals were enlarged up to 20 K file, and an Indian ink was injected into each canal. Then the Group I (n = 20) was treated with SAF, Group II (n = 20) with Rotary Protaper Universal and Group III (n = 20) with Hand K-files and the root canal cleaning efficacy was evaluated based on the amount of Indian ink remaining in the canal walls under stereomicroscopy. Data were analyzed using Kruskal-Wallis one way ANOVA test and post hoc Tuckey test for intragroup and intergroup comparison, respectively.

Results

A statistically highly significant difference was observed with SAF (mean = 1.5), Protaper (mean = 2.5), and Hand K-files (mean = 2.9). However, there was no significant difference in root canal cleaning efficacy with Protaper Universal and Hand K-files.

Conclusion

The SAFs had shown superior cleaning efficacy compared with rotary Protaper Universal and manual K files.

Comparative Molecular Analysis of Gram-Negative Bacteria in Primary Teeth with Irreversible Pulpitis or Periapical Pathology

Purpose: The purpose of this study was to compare the Gram-negative pathogens identified in the root canals of primary teeth with irreversible inflammatory pulpitis and in teeth showing apical periodontitis. Methods: Samples were collected from 123 root canals of primary teeth from three- to seven-year-old patients. Root canals were assigned to either group one (irreversible inflammatory pulpitis; <small>n</small> equals 63) or group two (pulp necrosis and apical periodontitis; n equals 60). Total number of cells of selected Gram-negative microorganisms was determined by the checkerboard DNA-DNA hybridization technique. Demographic data were compared using either chi-squared or t tests. Total numbers of microorganisms were compared using the Mann-Whitney test (α equals 0.05). Results: There were no significant intergroup differences in gender, age, and tooth group distribution (P>0.05). Among the 123 samples, 17 were discarded due to salivary contamination. The total numbers of Prevotella nigrescens, Treponema denticola, Fusobacterium nucleatum polymorphum, Fusobacterium nucleatum spp nucleatum, Aggregatibacter actinomycetemcomitans serotype a, Aggregatibacter actinomycetemcomitans serotype b, Porphyromonas gingivalis, Prevotella intermedia, and Prevotella melaninogenica were higher in teeth with apical periodontitis compared to those with irreversible inflammatory pulpitis (P<0.05). Conclusion: Higher numbers of Gram-negative bacteria were found in teeth with apical periodontitis compared to teeth with irreversible in- flammatory pulpitis.

Distinctions and associations between the microbiota of saliva and supragingival plaque of permanent and deciduous teeth

BACKGROUND

Using salivary microbiota as an accurate proxy for monitoring supragingival microbiota remains controversial because their relationship remains unclear. The eruption of permanent teeth and the exfoliation of primary teeth in mixed dentition greatly alter microbial habitats, which may cause compositional shifts of oral microbiota from childhood to adults.

OBJECTIVE

This study's purpose was to assess whether saliva represents a suitable sample for monitoring supragingival microbiota in healthy people, and to explore how the replacement process of deciduous teeth with permanent teeth in mixed dentition influences microbiota within the oral cavity.

DESIGN

Samples of saliva and of supragingival plaque from permanent and deciduous teeth were collected separately from 20 healthy children with mixed dentition. To characterize their microbial communities, we used the V3-V4 hypervariable region of the bacterial 16S rRNA gene sequence.

RESULTS

Saliva harbored a less even and less diverse community than did the plaque. Discriminating genera, namely Rothia and Streptococcus, contributed to the saliva and plaque differentiation. About half of predicted KEGG pathways varied between the plaque and saliva communities. Oral bacteria showed significantly associations between their supragingival and salivary states. We identified 20 supragingival plaque-related genera in saliva, such as Corynebacterium, Capnocytophaga, Fusobacterium, and Neisseria. Additionally, the relative abundance of Actinobacteria peaked in the permanent teeth plaque but subsided in deciduous teeth plaque and saliva. The exfoliation of deciduous teeth and eruption of permanent teeth might be related to the reported fluctuation in the relative abundance of Actinobacteria from primary dentition to permanent dentition within the oral cavity. The variation between PT and DT was due mainly to permanent teeth being enriched in Actinomyces and deciduous teeth in Treponema.

CONCLUSION

These results suggested that the supragingival plaque-related bacteria could be suitable candidates when sampling saliva for monitoring supragingival microbiota. The replacement process of deciduous teeth with permanent teeth in mixed dentition might be related to the reported age-maturation of phylum Actinobacteria in the oral cavity.

Structure of the Bacterial Community in Different Stages of Early Childhood Caries

PURPOSE

To characterise in vivo the structure of bacterial communities in decayed and sound primary teeth.

MATERIALS AND METHODS

Samples of biofilms were collected from three groups of patients with complete and exclusively primary dentition (n = 45): G1: sound teeth (n = 15); G2: enamel lesion (n = 15); G3: dentin lesion (n = 15). DNA was extracted (CTAB 2%) from the biofilm, the partial 16S rRNA gene was amplified with Bacteria Universal Primers (BA338fGC - UN518r) and subjected to DGGE (denaturing gradient gel electrophoresis). Multidimensional scaling and ANOSIM (analysis of similarity) were employed to determine the structure of the bacterial communities. The amplicon richness was determined by averaging amplicons, with the differences between treatments determined with ANOVA, while means were compared using Tukey's test (p < 0.05).

RESULTS

Compared to sound teeth, a greater variety of bacterial communities was found in decayed teeth. Despite the differences between the bacterial communities of sound teeth and decayed teeth, the Venn diagram showed that the samples had 38 amplicons in common. Greater amplicon richness was observed in samples of decayed teeth (enamel: 20.5 ± 2.7; dentin: 20.1 ± 2.8) compared with the sound samples (12.0 ± 4.3) (p <0.05), indicating enhanced growth for specific groups of bacteria on decayed teeth.

CONCLUSION

Although there is less bacterial diversity on sound than ECC-decayed teeth, the bacterial communities are very similar.

Antibiofilm Activity of Five Different Endodontic Filling Materials Used in Primary Teeth Using Confocal Laser Scanning Microscopy

PURPOSE

The purpose of this study was to evaluate the effect of five endodontic materials for primary teeth on in vitro mixed-species biofilms.

METHODS

Zinc oxide eugenol (ZOE) cement, Vitapex, Calen paste thickened with zinc oxide (ZO), pure calcium hydroxide (Ca(OH)2) paste, and iodoform were evaluated. Sterile water was used as a control. Mixed-species biofilm was incubated in anaerobic conditions for 21 days. The biofilm specimens were placed in contact with the endodontic materials for periods of seven and 30 days. The biofilm was studied by using confocal laser scanning microscopy. The cell viability ratio was calculated. The results were analyzed using analysis of variance and Tukey tests.

RESULTS

There was a statistically significant difference between groups at both seven and 30 days (F equals 73,073, P=0.00). After 30 days, 69 percent, 51 percent, and 35 percent of the biofilm volume fluoresced red, indicating the proportion of bacteria killed by iodoform, Vitapex, and ZOE cement, respectively. Calen plus ZO and pure Ca(OH)2 paste were the least effective materials against the biofilms.

CONCLUSIONS

Pure iodoform paste and iodoform containing Vitapex were the most effective materials against the biofilms. Vitapex appears to be a suitable endodontic material for primary teeth.

Supragingival Microbial Profiles of Permanent and Deciduous Teeth in Children with Mixed Dentition

Objectives

The present study was designed to investigate the microbial profiles of teeth in different locations in mixed-dentition-stage children, and to compare the microbiomes of permanent and deciduous teeth in the same healthy oral cavity.

Methods

Supragingival plaque samples of teeth in various locations—the first permanent molars, deciduous molars, deciduous canines and incisors and permanent incisors—were collected from 20 healthy mixed-dentition-stage children with 10–12 permanent teeth erupted. Plaque DNA was extracted, and the V3–V4 hypervariable region of the bacterial 16S rRNA gene was amplified and subjected to sequencing.

Results

On average, 18,051 high-quality sequences per sample were generated. Permanent tooth sites tended to host more diverse bacterial communities than those of deciduous tooth sites. A total of 12 phyla, 21 classes, 38 orders, 66 families, 74 genera were detected ultimately. Five predominant phyla (Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria and Actinobacteria) were highly variable among sites. Of 26 genera with a mean relative abundance of >0.1%, 16 showed significant differences in relative abundance among the groups. More than 20% of the total operational taxonomical units were detected only in permanent or deciduous teeth. The variation in the microbial community composition was due mainly to permanent teeth being enriched in Actinomyces and deciduous teeth in Treponema. The core microbiome of supragingival plaque in mixed dentition comprised 19 genera with complex correlationships.

Conclusion

Our results suggest differences in microbial diversity and composition between permanent and deciduous teeth sites in mixed dentition. Moreover, the core microbiome of these sites was determined. These findings enhance our understanding of the development of the native oral microbiota with age.

Correlation Between Bacterial Endotoxin Levels in Root Canals of Primary Teeth and the Periapical Lesion Area

PURPOSE

The purposes of this study were (1) to assess the endotoxin levels in root canals of primary teeth with necrotic pulps and periapical lesions; and (2) to evaluate the correlation of endotoxin levels with the periapical lesion size.

METHODS

Twenty primary molars with necrotic pulps and periapical lesions were selected. Standardized radiographs were obtained and the lesions were measured. Material from each root canal was collected to quantify the bacterial endotoxin. The results were analyzed using Pearson's correlation, student's t test, and Fisher's exact test (α equals five percent).

RESULTS

The initial amount of bacterial endotoxin in the root canals ranged from 0.089 to greater than 50.00 endotoxin units (EU)/mL and was detected in 100 percent of the samples. A positive but not significant correlation was observed between the amount of endotoxin and periapical lesion size in primary molars.

CONCLUSION

Endotoxin was observed in 100 percent of root canals of primary teeth with a periapical lesion. However, there was no statistical significance between bacterial endotoxin levels and the periapical lesion area.

Randomized in vivo evaluation of photodynamic antimicrobial chemotherapy on deciduous carious dentin

The aim of this randomized in vivo study was to compare antimicrobial chemotherapies in primary carious dentin. Thirty-two participants ages 5 to 7 years underwent partial caries removal from deep carious dentin lesions in primary molars and were subsequently divided into three groups: control [chlorhexidine and resin-modified glass ionomer cement (RMGIC)], LEDTB [photodynamic antimicrobial chemotherapy (PACT) with light-emitting diode associated with toluidine blue solution and RMGIC], and LMB [PACT with laser associated with methylene blue solution and RMGIC]. The participants were submitted to initial clinical and radiographic examinations. Demographic features and biofilm, gingival, and DMFT/DMFS indexes were evaluated, in addition to clinical and radiographic followups at 6 and 12 months after treatments. Carious dentin was collected before and after each treatment, and the number of Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, Fusobacterium nucleatum, Atopobium rimae, and total bacteria was established by quantitative polymerase chain reaction. No signs of pain or restoration failure were observed. All therapies were effective in reducing the number of microorganisms, except for S. sobrinus. No statistical differences were observed among the protocols used. All therapies may be considered as effective modern approaches to minimal intervention for the management of deep primary caries treatment.

Analysis of the Microbiota of Black Stain in the Primary Dentition

Black tooth stain is a characteristic extrinsic discoloration commonly seen on the cervical enamel following the contour of the gingiva. To investigate the relationship between black tooth stain and the oral microbiota, we used 16S rRNA gene sequencing to compare the microbial composition of dental plaque and saliva among caries-free children with and without black stain. Dental plaque and saliva, as well as black stain, were sampled from 10 children with and 15 children without black stain. Data were analyzed using the pipeline tool MOTHUR. Student’s t-test was used to compare alpha diversities and the Mann-Whitney U test to compare the relative abundances of the microbial taxa. A total of 10 phyla, 19 classes, 32 orders, 61 families and 102 genera were detected in these samples. Shannon and Simpson diversity were found to be significantly lower in saliva samples of children with black stain. Microbial diversity was reduced in the black stain compared to the plaque samples. Actinomyces, Cardiobacterium, Haemophilus, Corynebacterium, Tannerella and Treponema were more abundant and Campylobacter less abundant in plaque samples of children with black stain. Principal component analysis demonstrated clustering among the dental plaque samples from the control group, while the plaque samples from the black stain group were not and appeared to cluster into two subgroups. Alterations in oral microbiota may be associated with the formation of black stain.

Does the method of caries induction influence the bond strength to dentin of primary teeth?

PURPOSE

To evaluate the effect of chemical and microbiological methods of caries induction on microtensile bond strength (μTBS) of current adhesive systems to primary dentin.

MATERIALS AND METHODS

Flat dentin surfaces from 36 primary molars were assigned to 3 groups according to the method of inducing caries-affected dentin: (1) control (sound dentin); (2) pH cycling; and (3) microbiological. In both methods, teeth were submitted to caries induction for 14 days, and the sound dentin was stored in distilled water for the same period. Specimens were then randomly reassigned according to adhesive system: a two-step etch-and-rinse adhesive (Adper Single Bond 2) or a two-step self-etching system (Clearfil SE Bond). Composite buildups were constructed and the teeth were sectioned to obtain bonded sticks (0.8 mm2) to be tested for microtensile bond strength. The μTBS means were analyzed by two-way ANOVA and Tukey's tests (α = 0.05). Failure mode was evaluated using a stereomicroscope (400X).

RESULTS

Both methods of caries induction resulted in lower μTBS values (with no significant difference between them) than those obtained for sound dentin. Adhesive systems showed similar bond strength values. The percentage of premature failure was higher in the microbiological group, regardless of adhesive system.

CONCLUSION

Microbiological and pH-cycling methods are both suitable for simulating caries-affected dentin for bonding evaluations in primary teeth.

Salivary Candida species carriage patterns and their relation to caries experience among yemeni children

PURPOSE

This study was carried out to assess the carriage rates, counts and species distribution of Candida in saliva of 6- to 12-year-old Yemeni children and relate that to their caries experience.

MATERIALS AND METHODS

One hundred eighty children were recruited. Oral hygiene and caries were assessed using the simplified oral hygiene index and dft/DMFT index, respectively. Detection and quantification of 4 Candida species in unstimulated saliva were performed using CHROMagar Candida medium. Data were analysed using regression analysis.

RESULTS

Candida was detected in 60% of the children with a mean count of 923 ± 1875 CFU/ml. C. albicans accounted for 60% of the isolates and was the only species to be detected with more than 1000 CFU/ml. Non-albicans candida and unidentified species represented 16.3% and 23.1% of the isolates, respectively. One novel finding was that a significant proportion (38%) of the carriers harboured two or more species, which for the first time allowed the identification of four age-dependent carriage patterns (clusters). Another somewhat new observation was that carriage at ≥ 1000 CFU/ml in particular significantly correlated with caries in primary and permanent dentitions (r = 0.23 and 0.18, respectively) as well as a caries-active status (OR = 6.9). Interestingly, the C. glabrata cluster had significantly lower primary caries scores than other clusters.

CONCLUSIONS

The findings substantiate claims of geographical variations in candida carriage and the relation between candida carriage and caries. The validity of carrier clusters and the use of 1000 CFU/ml as a risk marker should be further investigated.

Chair-side quantitative oral-microflora screening for assessing familial correlation of periodontal status and caries prevalence

Aim: Our goal was to investigate the relationship between clinical status and the presence of carious or periodontal pathogens among parent-child familial pairs. Clinical practices of risk assessment with consideration of familial pathogen interaction might reduce the need for therapy, improve patient outcomes, and ultimately reduce oral disease burden. Materials and Methods: In this study, we enrolled 30 parent-child pairs, with the children exhibiting complete deciduous dentition or mixed dentition with only permanent first molars. Clinical statuses were evaluated using caries and periodontal disease indicators, including the sum of decay and the number of missing or filled teeth (DMFT) for adults, decay, extraction caused by dental disease, and filled teeth (deft), for children, probing depth, and plaque control record (PCR). Supra- and sub-gingival bacteria were determined based on semi-quantitative measurements of microbial infection by using data from the Dentocult^® SM test (caries-related organisms) and the PerioCheck^® test (periodontal disease-related organisms). Results: No statistically significant relationship was detected between the prevalence of periodontal pathogens and that of cariogenic pathogens in the oral cavity. However, the clinical status of caries (DMFT) was negatively correlated with the clinical status of periodontal disease (pocket depth) in parents who were infected with dominant periodontal pathogens (r = −0.59, p<0.01). Parents’ DMFT scores were positively correlated with children’s deft and PCR scores. PCR and deft scores of children appeared to decrease significantly with the parent’s pocket depth. Conclusion: The study showed that the quantity of caries pathogens were not significant related to periodontal pathogens, but the caries clinical outcome is negative related with periodontal clinical outcome between familial pairs.

Efficacy of Papacarie(®) in reduction of residual bacteria in deciduous teeth: a randomized, controlled clinical trial

OBJECTIVES

The aim of the present study was to analyze the efficacy of Papacarie(®) gel compared with the traditional method (low-speed bur) in reducing the counts of total bacteria, Lactobacillus, total Streptococcus and Streptococcus mutans group.

METHODS

A randomized, controlled clinical trial with a split-mouth design was performed. The sample comprised 40 deciduous teeth in 20 children (10 males and 10 females) aged four to seven years. The teeth were randomly allocated to two groups: G1, or chemomechanical caries removal with Papacarie Duo(®), and G2, or the removal of carious dentin tissue with a low-speed bur. Infected dentin was collected prior to the procedure, and the remaining dentin was collected immediately following the removal of the carious tissue. Initial and final counts of bacterial colonies were performed to determine whether there was a reduction in the number of colony-forming units (CFUs) of each microorganism studied. ClinicalTrials.gov: NCT01811420.

RESULTS

Reductions were found in the numbers of total bacteria, total Streptococcus and Streptococcus mutans group following either of the caries removal methods (p<0.05). A reduction was also noted in the number of Lactobacillus CFUs; however, this difference did not achieve statistical significance (p>0.05).

CONCLUSION

Papacarie(®) is an excellent option for the minimally invasive removal of carious tissue, achieving significant reductions in total bacteria, total Streptococcus and S. mutans with the same effectiveness as the traditional caries removal method.

Preliminary molecular analysis of bacterial composition in periapical lesions with primary endodontic infections of deciduous teeth

BACKGROUND

The bacterial composition of periapical lesions in deciduous teeth has not been well documented. This study was designed to explore the bacterial compositions, especially the dominant bacteria in periapical lesions using 16S rRNA sequencing.

METHODS

Tissue samples were collected from 11 periapical lesions in deciduous teeth with primary endodontic infections. DNA was extracted from each sample and analyzed using 16S rRNA cloning and sequencing for the identification of bacteria.

RESULTS

All DNA samples were positive for 16S rRNA gene PCR. One hundred and fifty-one phylotypes from 810 clones were identified to eight phyla, and each sample contained an average of 25.9 phylotypes. In addition, 59 phylotypes were detected in more than two samples, and Fusobacterium (F.) nucleatum (8/11), Dialister (D.) invisus (8/11), Campylobacter (C.) gracilis (7/11), Escherichia (E.) coli DH1 (6/11), Aggregatibacter (A.) segnis (6/11), and Streptococcus (S.) mitis (6/11) were the most prevalent species. Furthermore, 45 as-yet-uncultivated phylotypes were also identified.

CONCLUSIONS

Chronic periapical lesions in deciduous teeth contained polymicrobial infections. F. nucleatum, D. invisus, C. gracilis, E. coli DH1, A. segnis, and S. mitis were the most prevalent species detected by 16S rRNA sequencing.

Incomplete caries removal and indirect pulp capping in primary molars: a randomized controlled trial

PURPOSE

To compare the effect of incomplete caries removal (ICR) and indirect pulp capping (IPC) with calcium hydroxide (CH) or an inert material (wax) on color, consistency and contamination of the remaining dentin of primary molars.

METHODS

This double-blind, parallel-design, randomized controlled trial included 30 children presenting one primary molar with deep caries lesion. Children were randomly assigned after ICR to receive IPC with CH or wax. All teeth were then restored with resin composite. Baseline dentin color and consistency were evaluated after ICR, and dentin samples were collected for contamination analyses using scanning electron microscopy. After 3 months, restorations were removed and the three parameters were re-evaluated. In both groups, dentin became significantly darker after 3 months.

RESULTS

No cases of yellow dentin were observed after 3 months with CH compared to 33.3% of the wax cases (P < 0.05). A statistically significant difference over time was observed only for CH regarding consistency. CH stimulated a dentin hardening process in a statistically higher number of cases than wax (86.7% vs. 33.3%; P = 0.008). Contamination changed significantly over time in CH and wax without significant difference between groups. It was concluded that CH and wax arrested the carious process of the remaining carious dentin after indirect pulp capping, but CH showed superior dentin color and consistency after 3 months.

Streptococcus sobrinus in children and its influence on caries activity

AIM

This was to study the longitudinal assessment of caries activity of Streptococcus sobrinus (SS) positive children during their mixed dentition.

METHODS

The occurrence of mutans streptococci (MS) in plaque and saliva was determined in a representative sample of 55 children aged 8 to 12 years over a period of 4 years. A total of 708 bacterial strains was isolated which were identified as MS or SS. Caries activity (DeltaD(1-4)MFS) as well as plaque and gingival inflammation were recorded.

RESULTS

During the period of observation 52 of the 55 children harboured MS; 12 of these children were SS positive. SS was not permanently detectable and 3 of the children were MS and SS negative. SS was not found without the presence of MS. Children that were infected with both SS and MS showed a slightly higher increase in caries compared with children that were infected exclusively by MS (DeltaD(1,2)MFS 6.2 vs. 3.0 and DeltaD(3,4)MFS 5.3 vs. 3.8) over the period of 4 years. An SS infection accelerated the increase of DeltaD(3,4)MFS significantly by a factor of 4 one year after its detection, whereas the DeltaD(1,2)MFS was 3 times as high during the period of infection.

CONCLUSION

The findings suggest that an SS infection represents an important additional risk factor for dental caries due to its obvious aggravating of caries activity.

Live Helicobacter pylori in the root canal of endodontic-infected deciduous teeth

BACKGROUND

Many polymerase chain reaction (PCR)-based studies have shown that Helicobacter pylori DNA is prevalent in the oral cavity, but reports on the isolation of live bacteria are extremely rare. Thus, it is still unclear whether H. pylori can indeed survive in the oral environment.

METHODS

Here we used electron microscopy, selective growth techniques, urease assays, 16S rRNA PCR, and western blotting to investigate the possible presence of live H. pylori in 10 root canal and corresponding plaque samples of endodontic-infected deciduous teeth in three children.

RESULTS

Although H. pylori DNA was verifiable by PCR in several plaque and root canal samples, bacterial colonies could only be grown from two root canals, but not from plaque. These colonies were unequivocally identified as H. pylori by microscopic, genetic, and biochemical approaches.

CONCLUSIONS

Our findings show that root canals of endodontic-infected teeth may be a reservoir for live H. pylori that could serve as a potential source for transmission.

Infection from an exfoliating primary tooth in a child with severe neutropenia: a case report

In patients with deficient immune defenses, a localized oral infection can progress to a systemic infection. The purpose of this paper was to describe the case of a child with acute lymphoblastic leukemia who presented with fever, trismus, and submandibular swelling in the absence of the typical dental causes of infection such as deep dental caries or clinically significant periodontal disease. Treatment included an aggressive intravenous antibiotic regimen and extraction of the offending tooth after the recovery from bone marrow suppression.

Prevention-centered caries management strategies during critical periods in early childhood

The current caries management model in the United States is based on restoring teeth rather than preventing disease. Scarce resources make this approach unsustainable, especially in clinical settings that serve vulnerable child populations. This paper presents specific prevention-centered caries management strategies that should form the basis of clinical interventions targeted at children during four critical periods in childhood: pre-age 1, ages 1-3, ages 4-5, and ages 6-7.

A microbiological assessment of polymer and conventional carbide burs in caries removal

PURPOSE

The purpose of this study was to compare the caries removal efficiency of polymer burs (Smartburs) and conventional carbide burs microbiologically.

METHODS

Twenty-four patients participated, each presenting 2 active carious lesions on the occlusal surfaces of primary molars. Sample-taking and caries-removal were done in the following order: (1) first sample (from the carious dentin); (2) caries removal (with a Smartbur or carbide bur); and (3) second sample (from the caries-free dentin), respectively. The samples were processed in a laboratory and spread on various media. The colonies on the agar plates were counted, and then numbers of CFU/ml were calculated.

RESULTS

There were no statistically significant differences between the numbers of CFU/ml in the carious dentin before preparation, comparing the Smartbur group and carbide bur group for all the media used (P>.05). There were statistically significant differences in the numbers of CFU/ml before and after preparation comparing both types of burs for all the media used (P<.05). There were no statistically significant differences in the reductions of the numbers of CFU/ml, comparing the 2 preparation instruments (P>.05).

CONCLUSION

The polymer burs were found as effective as the conventional carbide burs microbiologically in caries removal.

Fluorescence-aided caries excavation (FACE), caries detector, and conventional caries excavation in primary teeth

PURPOSE

The purpose of this paper was to compare the ability of fluorescence-aided caries excavation (FACE) to remove infected dentin in primary teeth with that of conventional methods.

METHODS

Sixty-six extracted carious primary teeth were divided according to lesion size into 3 groups of 22 teeth. Caries excavation was carried out with a slow-speed handpiece and round burs for all groups. In the first group, caries was excavated conventionally using visual tactile criteria. In the second group, a caries detector dye was used to detect carious dentin. In the FACE group, cavities were excited with violet light (370-420 nm) and observed through a 530 nm highpass filter. Orange-red fluorescing areas were removed. Undecalcified thin slices were prepared, stained with Giemsa, and examined for presence of infected dentin using light microscopy. Four samples were lost during processing.

RESULTS

Histology showed infected dentin in significantly less FACE samples (3 of 22) compared to conventional excavation (9 of 20; P=.03), but not significantly less compared to caries detector (5 of 20; P=.35).

CONCLUSIONS

Within the limitations of this in vitro study, it can be concluded that fluorescence-aided caries excavation is more effective than conventional excavation in removal of infected primary dentin.

Early colonization of mutans streptococci in 2- to 36-month-old Thai children

PURPOSE

The purpose of this study was to determine the timing of colonization of streptococci mutans (SM) in 2- to 36-month-old Thai children.

METHODS

Two hundred and two 2- to 36-month-old children were divided into 3 groups: group 1 = 84 predentate children; group 2 = 68 children with 1 to 8 erupted teeth; and group 3 = 50 children with 9 to 20 erupted teeth. Microbiological samples were obtained from children by cotton swab. Samples were diluted and plated on mitis salivarius agar supplemented with Baocitracin (MSB) for selection and enumeration of SM.

RESULTS

SM colonization was found in 26% of children, who had a mean age in months of 20.5 +/- 103 (SD). MS colonization was detected in 5% of predentate children and was detected in children as young as 2 months old. The percentage of children who were colonized with SM rose significantly with increasing age and numbers of erupted teeth (P < .001).

CONCLUSIONS

Streptococci mutans colonization in 2- to 36-month-old Thai children was found in predentate children and detected in children as young as 2 months old. The results suggest that prevention of early SM colonization in some populations may need to be initiated prior to tooth eruption.

Photodynamic therapy in endodontic treatment of deciduous teeth

The purpose of this study was to evaluate photodynamic therapy in deciduous teeth with necrotic pulp by means of fully quantifying viable bacteria, before and after instrumentation and after the use of photodynamic therapy. Radicular canal cultures were conducted (n = 10): the first one was performed right after access and location of the radicular canal; the second was performed after the conclusion of chemical-mechanical instrumentation, and the last one after photodynamic therapy. The photodynamic therapy was performed with 4 J/cm energy low-intensity diode together with toluidine blue. The results (log(10)) were submitted to a descriptive analysis and Wilcoxon test. The percentage of reduction was submitted to the Mann-Whitney test. The instrumentation resulted in a reduction of 82.59% of viable bacteria, and, after photodynamic therapy, the microbial reduction observed was 98.37% (P = 0.0126). Photodynamic therapy is recommended as adjunct therapy for microbial reduction in deciduous teeth with necrotic pulp.

Bacteria of dental caries in primary and permanent teeth in children and young adults

Although Streptococcus mutans has been implicated as a major etiological agent of dental caries, our cross-sectional preliminary study indicated that 10% of subjects with rampant caries in permanent teeth do not have detectable levels of S. mutans. Our aims were to use molecular methods to detect all bacterial species associated with caries in primary and permanent teeth and to determine the bacterial profiles associated with different disease states. Plaque was collected from 39 healthy controls and from intact enamel and white-spot lesions, dentin lesions, and deep-dentin lesions in each of 51 subjects with severe caries. 16S rRNA genes were PCR amplified, cloned, and sequenced to determine species identities. In a reverse-capture checkerboard assay, 243 samples were analyzed for 110 prevalent bacterial species. A sequencing analysis of 1,285 16S rRNA clones detected 197 bacterial species/phylotypes, of which 50% were not cultivable. Twenty-two new phylotypes were identified. PROC MIXED tests revealed health- and disease-associated species. In subjects with S. mutans, additional species, e.g., species of the genera Atopobium, Propionibacterium, and Lactobacillus, were present at significantly higher levels than those of S. mutans. Lactobacillus spp., Bifidobacterium dentium, and low-pH non-S. mutans streptococci were predominant in subjects with no detectable S. mutans. Actinomyces spp. and non-S. mutans streptococci were predominant in white-spot lesions, while known acid producers were found at their highest levels later in disease. Bacterial profiles change with disease states and differ between primary and secondary dentitions. Bacterial species other than S. mutans, e.g., species of the genera Veillonella, Lactobacillus, Bifidobacterium, and Propionibacterium, low-pH non-S. mutans streptococci, Actinomyces spp., and Atopobium spp., likely play important roles in caries progression.

Histopathologic study of physiological and pathological resorptions in human primary teeth

This study presents a histological analysis through optical microscopy of primary teeth with physiological and pathological resorptions to outline the histological profile of resorptions. Sixty teeth were examined: 19 primary teeth with physiological resorption and 41 primary teeth with pathological resorption. To analyze the histological conditions of the pulp, periradicular tissue, and the resorption areas, and to investigate the presence, intensity, and location of bacteria, slides were prepared using the hematoxylin-eosin and the Brown-Brenn techniques. For the teeth with physiological resorption, normal pulps and no evidence of bacteria were found. For the teeth with pathological resorption, pulpal alterations, atypical resorption, and bacteria were observed.

Prevention of maternal bacterial transmission on children's dental-caries-development: 4-year results of a pilot study in a rural-child population

AIM

Dental caries with its bacterial agent is an infectious disease, and shows a vertical transmission. The control of bacterial transmission of Mutans streptococci (MS) from mother to child has been studied, and its results on their children's caries development, and on their siblings' bacterial levels, have been analysed in a field-trial (for 4 years) in rural area.

MATERIAL AND METHODS

In the same tribe, 8 mothers and their 11 children (test children [TC]), and then (following years) their 9 siblings (test sibling [TSb]), were followed for 4 years. The study started when the TC group had just started to erupt. Test mothers were subjected to a preventive regime. Examination of caries development as well as determination of plaque levels of MS in TC and TSb were carried out annually and at 6-month intervals. At the end of 4 years, two control groups (control children [CC] and control siblings [CSb]) resembling TC and TSb were selected from the other tribe living in the same village, and bacterial data and caries status were compared to both test groups.

RESULTS

Microbial data demonstrated that the test children (p<0.01) and test siblings (p<0.05) had significantly low bacterial level in plaque samples. Accordingly, TC had significantly low dmf-t and -s number compared to corresponding control group (p<0.001 for dmf-t, p<0.0001 for dmf-s).

CONCLUSION

The preventive regimen was applicable in rural southeastern Anatolia, where an introverted life style with a great tribal system is prevailing, any other preventive measures may have been practical or available, and babies are basically cared by mothers.

Assessment of the microbiota in root canals of human primary teeth by checkerboard DNA-DNA hybridization

PURPOSE

The purpose of this study was to evaluate in vivo the prevalence of microorganisms in root canals of human primary teeth, by checkerboard DNA-DNA hybridization.

METHODS

Fifty-five root canals of primary teeth with irreversible pulpitis (group 1) and 51 root canals of teeth with pulp necrosis and apical periodontitis (group 2) were selected. Microbiological samples were collected and submitted to checkerboard DNA-DNA hybridization using 34 genomic DNA probes. The results were analyzed statistically by Mann-Whitney U-test at a 5% significance level.

RESULTS

The most prevalent species in group 1 were: (1) Campylobacter rectus (87%); (2) Gemella morbilorum (78%); (3) Streptococcus gordonii (71%); (4) Capnocytophaga ochracea (69%); (5) Treponema denticola (58%); and (6) Streptococcus intermedius (49%). The most prevalent species in group 2 were: (1) C. rectus (90%); (2) T. denticola (88%); (3) S. intermedius (77%); (4) G. morbilorum (73%); (5) Streptococcus oralis (67%); (6) C. ochracea (63%); (7) S. gordonii (55%); (8) Streptococcus mitis (51%); and (9) Leptotrichia buccalis (51%). Except for Peptostreptococcus micros and Actinomyces israelii, the most prevalent bacterial strains in the root canals with apical periodontitis were also those found in larger numbers (P<.05). Groups 1 and 2 differed significantly (P<.05) regarding the total number of bacterial cells detected in the root canal samples, with group 2 showing remarkably larger bacterial cell numbers.

CONCLUSIONS

Root canals of primary teeth have a great bacterial diversity, characterizing a polymicrobial endodontic infection with presence of: (1) anaerobic and facultative micro organisms; (2) black-pigmented rods; and (3) streptococci. A large number of anaerobic species were detected in teeth with necrotic pulp and apical periodontitis, and a significantly smaller number of bacterial cells were found in teeth with irreversible pulpitis.

Ultrastructural and microbiological analysis of the dentin layers affected by caries lesions in primary molars treated by minimal intervention

PURPOSE

The purpose of this in vivo study of primary teeth was to analyze the ultrastructure and microbiology of dentin layers affected by caries lesions before and after restorations with resin-modified glass ionomer.

METHODS

Samples of carious dentin from primary teeth removed prior to restoration placement (baseline-0 day) were compared with samples taken after 30 and 60 days. Dentin from 8 primary molars was analyzed by scanning electron microscopy (SEM) and dentin from 22 primary molars was examined microbiologically to compare bacteria (total of viable counts, Streptococcus spp, Streptococcus mutans, Lactobacillus spp, and Actinomyces spp) before and after treatment (30 and 60 days).

RESULTS

Baseline caries samples had enlarged dentinal tubules with bacteriol invasion. SEM samples after treatment suggest better tissue organization, with more compact collagen fibers arrangement and narrower dentinal tubules. The number of bacteria decreased in all samples at both 30 (98%) and 60 (96%) days, with all bacteria species showing similar trends.

CONCLUSIONS

The minimal intervention approach is very effective to promote beneficial changes in the lesion environment and favorable conditions for the healing process in primary teeth.

Salivary mutans streptococci counts as indicators in caries risk assessment in 6–7-year-old Chinese children

OBJECTIVES

This study aimed to determine whether salivary mutans streptococci (MS) counts in Chinese children had any value in the prediction of new caries in the permanent dentition in the age interval of 6.5-8.5 years.

METHODS

Four hundred and thirty-three 6-7-year-old children participated in this 2-year longitudinal study. Salivary MS counts were obtained at baseline with the spatula method. Dentin and enamel caries was recorded at baseline and at the follow-up, 2 years later. Spearman's correlation coefficients were computed. Past caries experience variables at baseline were entered into a multiple regression model with caries increment of the permanent dentition as dependent variable. MS counts were subsequently entered into the model to assess the additional caries predictive value.

RESULTS

Spearman's correlation coefficient for MS counts and caries experience of the primary dentition at baseline was 0.48 and for MS counts and caries increment in the permanent dentition 0.12. In the multiple regression model caries increment of the permanent dentition had an adjusted R2 of 0.17 when the past caries experience variables were entered. Adding MS counts in the regression model did not change the R2 value.

CONCLUSIONS

Salivary MS counts did not add any caries predictive value when past caries experience variables were used as caries predictors in this Chinese child population.

Efficacy of various intracanal medicaments against Enterococcus faecalis in primary teeth: an in vivo study

The aim of this study was to evaluate the in vivo efficacy of three intracanal medicaments (Ca(OH)2, 1% chlorhexidine gel and 1% chlorhexidine gel with Ca(OH)2 against Enterococcus faecalis in necrotic primary teeth. As a conclusion, chlorhexidine gel with or without Ca(OH)2 was more effective than Ca(OH)2 alone against Enterococcus faecalis.

Mutans streptococci: acquisition and transmission

Dental caries is an infectious and transmissible disease. The mutans streptococci (MS) are infectious agents most strongly associated with dental caries. Earlier studies demonstrated that infants acquire MS from their mothers and only after the eruption of primary teeth. More recent studies indicate that MS can colonize the mouths of predentate infants and that horizontal as well as vertical transmission does occur. The purpose of this paper was to demonstrate that these findings will likely facilitate the development of strategies to prevent or delay infant infection by these microbes, thereby reducing the prevalence of dental caries.

Effect of mixed mutans streptococci colonization on caries development

OBJECTIVE

To evaluate the clinical importance of mixed mutans streptococci colonization in predicting caries in preschool children.

METHODS

Caries prevalence was examined twice, with a 6-month interval, in 410 preschool children aged 3-4 years at baseline. A commercial strip method was used to evaluate the mutans streptococci score in plaque collected from eight selected interdental spaces and in saliva. Mutans streptococci typing polymerase chain reaction (PCR) assays (Streptococcus sobrinus and Streptococcus mutans, including serotypes c, e, and f) were performed using colonies on the strips as template.

RESULTS

Twenty variables were examined in a univariate analysis to predict caries development: questionnaire variables, results of clinical examination, mutans streptococci scores, and PCR detection of S. sobrinus and S. mutans (including serotypes c, e, and f). Sixteen variables showed statistically significant associations (P < 0.04) in the univariate analysis. However, when entered into a logistic regression, only five variables remained significant (P < 0.05): caries experience at baseline; mixed colonization of S. sobrinus and S. mutans including S. mutans serotypes; high plaque mutans streptococci score; habitual use of sweet drinks; and nonuse of fluoride toothpaste.

CONCLUSION

'Mixed mutans streptococci colonization' is a novel measure correlated with caries development in their primary dentition.

Bacterial profile in primary teeth with necrotic pulp and periapical lesions

The objective of this study was to evaluate the bacterial profile in root canals of human primary teeth with necrotic pulp and periapical lesions using bacterial culture. A total of 20 primary teeth with necrotic pulp and radiographically visible radiolucent areas in the region of the bone furcation and/or the periapical region were selected. After crown access, 4 sterile absorbent paper points were introduced sequentially into the root canal for collection of material. After 30 s, the paper points were removed and placed in a test tube containing reduced transport fluid (RTF) and were sent for microbiological evaluation. Anaerobic microorganisms were found in 100% of the samples, black-pigmented bacilli in 30%, aerobic microorganisms in 60%, streptococci in 85%, Gram-negative aerobic rods in 15% and staphylococci were not quantified. Mutans streptococci were found in 6 root canals (30%), 5 canals with Streptococcus mutans and 1 canal with Streptococcus mutans and Streptococcus sobrinus. It was concluded that in root canals of human primary teeth with necrotic pulp and periapical lesions, the infection is polymicrobial with predominance of anaerobic microorganisms.

Dental caries: an infectious and transmissible disease where have we been and where are we going?

Dental caries is often referred to as an infectious disease, which means different things to different people. Pediatric dentists may be tempted to liken caries to other childhood diseases they encounter yet treat caries from mostly a mechanical or surgical approach. On the other end of the spectrum are clinicians who view the oral cavity as a site teaming with bacteria and think that reducing the overall microbial mass using antimicrobial agents will somehow affect this infectious disease. Here, we argue for another view, that is, to combine the most effective portion of each therapy to yield an effective outcome: the treatment and prevention of dental caries. Because primary teeth are eventually shed, pediatric dentists may be in an advantageous position to implement this approach since restorations to primary teeth need not be as durable as those made to permanent teeth. Moreover, pediatric dentists use sealants extensively and are used to working, for example, with rubber dams, especially in young patients. It may turn out that after more research is completed on the ontogeny of the oral microbial flora, changes or ecological shifts made in childhood become lifelong. More specifically, drastic reductions or eliminations of cariogenic bacteria, along with their sites for colonization in the primary dentition, may prevent or delay their transfer to the permanent dentition. Similarly, reductions in a mother's levels of cariogenic bacteria may delay or interrupt the transfer of cariogenic bacteria to her infant. Here, the goal is to discuss several concepts before their final inception into practices and to stimulate discussion of ideas, reframing the design to meet the demands of everyday practice. Ultimately, the proof will come from a large clinical trial conducted in many practices and patient populations.

Development of clinical and radiographic signs associated with dark discolored primary incisors following traumatic injuries: a prospective controlled study

The purpose was to evaluate late complications of asymptomatic traumatized primary incisors with dark coronal discoloration. The clinical and radiographic signs of 97 teeth of the study group were recorded along a follow-up period that ranged between 12 and 75 months (mean >36 months). Children's age at time of injury ranged between 18 and 72 months (mean 40). The control group consisted of 102 non-discolored maxillary primary central incisors in 51 children older than 54 months with no history of dental trauma. In 50 teeth (52%) the color faded or became yellowish and in 47 (48%) it remained dark. Clinical signs of infection, that were diagnosed 5-58 months after the injury, were associated significantly more with dark than yellowish hues (83 and 17%, respectively). Teeth that had changed their color to become yellow presented more PCO than teeth with black/gray/brown coronal discoloration (78 and 6%, respectively). Arrest of dentine apposition was found in 15 teeth, one had yellow coronal discoloration and the remaining 14 had a dark shade. Eleven teeth showed inflammatory root resorption all with dark discoloration. Two atypical types of root resorption were observed: a surface resorption restricted to the lateral aspects of the apical half of the root while the root length remained unchanged and in the other expansion of the follicle of the permanent successor was observed. Expansion of the dental follicle was observed in 72% of all teeth with no significant difference between the various types of coronal discoloration but only half of the cases were associated with resorption of the root of the primary incisor. The various pathologic findings observed in the study group were either absent or rarely seen in the control group. It can be concluded that more than 50% of the primary incisors that retain their dark coronal discoloration acquired after dental injuries remain clinically asymptomatic till the eruption of the permanent successor even if they present accelerated root resorption. Asymptomatic traumatized primary incisors that retain their dark coronal discoloration may develop a sinus tract and inflammatory root resorption years after the injury. There is still a dilemma: which treatment is better for dark discolored primary incisors: early endodontic treatment or follow-up with the risk of development of infection and root resorption that may require extraction?

Colonization of Streptococcus mutans and Streptococcus sobrinus Genotypes and Caries Development in Children to Mothers Harboring Both Species

The major route of early acquisition of mutans streptococci in humans is a vertical transmission from mother to child. The purpose of this longitudinal study was to examine the acquisition, distribution and persistence of Streptococcus mutans and Streptococcus sobrinus in children whose mothers harbored both species and to study the caries incidence in relation to colonization of these bacteria. Fifteen mother-child pairs were followed during the child's first 7 years. Stimulated salivary samples were taken from the mothers and the children. Plaque samples were also collected from the teeth and the tongue of the children. The samples were analyzed by cultivating techniques together with genomic fingerprinting and hybridizing. The caries experience was evaluated on the sampling occasions and retrospectively using the records of caries registrations from the community clinics. During the 7-year period 10 of the 15 children acquired mutans streptococci. Only 4 of them were colonized by both S. mutans and S. sobrinus despite the fact that their mothers harbored both species. In 2 of the children S. sobrinus was found later than S. mutans. A total of 26 genotypes were found in the children and 9 of them were identical to their mothers. New genotypes and a gain-loss pattern were noted especially in the children but also in their mothers. The groups of teeth first positive for the two species were the deciduous molars. The caries experience was low during the study period with 8 children showing no caries.

Prevalence of microorganisms in root canals of human deciduous teeth with necrotic pulp and chronic periapical lesions

The objective of this study was to evaluate bacterial prevalence in 31 root canals of human deciduous teeth with necrotic pulp and periapical lesions using bacterial culture. After crown access, the material was collected using absorbent paper points for microbiological evaluation and determination of colony forming units (CFU). Anaerobic microorganisms were found in 96.7% of the samples, black-pigmented bacilli in 35.5%, aerobic microorganisms in 93.5%, streptococci in 96.7%, and S. mutans in 48.4%. We concluded that in human deciduous teeth root canals with necrotic pulp and periapical lesions the infection is polymicrobial, with a large number of microorganisms and a predominance of streptococci and anaerobic microorganisms.

Actinomyces spp. in supragingival plaque of ethnic Chinese preschool children with and without active dental caries

Very limited molecular epidemiological data are available on the role of Actinomyces spp. in the pathogenesis of caries in the primary dentition. Therefore, we investigated their distribution in supragingival plaque of ethnic Chinese preschool children from Singapore and Hong Kong, either with or without active caries. Plaque samples were taken from intact interproximal enamel areas using dental floss. Bacterial genomic DNA of each sample was extracted and variable regions of 16S ribosomal DNA amplified and labelled with digoxigenin. Oligonucleotide probes specific for Actinomyces bovis, Actinomyces gerencseriae, Actinomyces israelii, Actinomyces meyeri, Actinomyces odontolyticus, catalase-negative Actinomyces naeslundii (genospecies 1 and 2) and catalase-positive Actinomyces naeslundii genospecies 2 (previously Actinomyces viscosus serotype II) were used to detect these species using Southern hybridization with a Minislot and Miniblotter system. A. odontolyticus, A. gerencseriae and A. meyeri were detected with similar frequency in both Singapore and Hong Kong samples or in those with and without active caries. However, the prevalence of A. naeslundii was significantly different in the two locales (p<0.05). A. odontolyticus (88.7%), A. gerencseriae (56.6%) and A. naeslundii (50.9%) were detected in a majority of the samples and the positive hybridization signals of A. gerencseriae in the caries-active group were stronger than from the caries-free group. A. bovis and A. israelii were undetectable in any of the samples. These data imply that A. odontolyticus, A. naeslundii and A. gerencseriae may play an important role in supragingival plaque formation on primary teeth in ethnic Chinese, with others such as A. meyeri contributing.

Evaluation of mutans streptococci in plaque and saliva: correlation with caries development in preschool children

OBJECTIVES

To test the ability of a site-specific method of evaluating mutans streptococci (MS) present in plaque in order to predict caries risk in children and to compare the results with those obtained from estimating the levels of MS present in saliva.

METHODS

Caries prevalence was examined twice, 6 months apart, in 129 preschool children ranging in age from 1.5 to 5. A commercial strip method was used to evaluate the MS score (0-3) in plaque collected from four selected tooth surfaces at two interdental spaces and in saliva.

RESULTS

The screening criteria of the MS score for caries incidence between scores 1 and 2, and scores 0 and 1 were the most valid for evaluating plaque (accuracy of prediction, 80%) and saliva (accuracy of prediction, 71%), respectively. Based on these screening criteria, the evaluation of saliva MS was invalid when the plaque MS score was considered. Screening plaque MS was effective, regardless of caries experience at baseline, according to the chi-square test (p<0.01), but screening saliva MS was ineffective when caries experience was present at baseline. A multivariate logistic regression analysis including six variables showed that the plaque MS score and caries experience at baseline were significantly correlated with caries incidence: caries experience at baseline (OR=5.02, 95%CI: 1.81-14.59) and high plaque MS score (2 or 3) (OR=12.59, 95%CI: 3.18-67.08).

CONCLUSIONS

These results suggest that the semi-quantitative evaluation of plaque MS sampled from only two proximal sites on the molars is more effective for screening preschool children at a high risk of developing caries in their primary dentition than other important caries risk indicators.

Accidentally induced periodontitis in primary dentition: longitudinal examinations of periodontal bacteria and clinical conditions

Periodontitis is very rare in the primary dentition although it can be accidentally induced in young children. The purpose of this study was to describe a case of periodontitis in a 4-year-old child, which was accidentally induced by insertion of small plastic tubes into the dental cervix of the primary incisors during play, and to discuss the clinical, radiographic, and microbiological findings. Removal of the plastic tubes resulted in resolution of the periodontal condition. Prevotella nigrescens and Campylobacter rectus were detected in subgingival plaque samples from the affected teeth at every examination, whereas Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, and Bacteroides forsythus were never found during the two-year observation period. The clinical and microbiological results suggest that the type of periodontitis caused by such an incidence is not progressive, unlike other periodontal diseases such as prepubertal and juvenile periodontitis.

[Clinical studies of calcium hydroxide disinfecting infectious root canal of deciduous tooth]

OBJECTIVE

To search for a more ideal way to disinfect infectious root canal of deciduous tooth.

METHODS

According to bacterial occurrence and clinical effect, 40 cases of infectious root canal of deciduous teeth disinfected with Ca(OH)2 were investigated, the other 40 cases with traditional way of using FC and CP respectively, were used as the control.

RESULTS

Fist of all, the bacteria of deciduous tooth infectious root canal were same as the bacteria of permanent tooth infectious root canal. Secondly, Ca(OH)2 was stronger in disinfecting deciduous tooth infectious root canal. Thirdly, so far as sterilization was concerned, Ca(OH)2 had the same disinfectant as FC, and was better than CP, but FC had some irritation and poisonous side-effects to periodical tissue. So Ca(OH)2 was safe and effective for deciduous tooth infectious root canal.

CONCLUSION

It was a more ideal way to disinfect deciduous tooth infectious root canal by Ca(OH)2.

The effect of choosing different units of analysis when estimating risk of presence of dental caries in the primary dentition

BACKGROUND

Data on caries are usually collected with the tooth surface or the tooth as the unit, but subsequently analysed by aggregating the data at the level of the individual.

AIMS

To evaluate how different units of analysis may affect the result of the statistical analyses in a study of the association between deciduous dental caries and a set of risk factors.

METHOD

293 children (mean age: 7.5 yrs) from two primary schools in Dar es Salaam, Tanzania were examined. Thus the study design was cross-sectional. Logistic regression analysis was used to determine the association between caries experience and nutritional status, socioeconomic background, and microbiological and salivary characteristics using the subject, the tooth, and the tooth surface as unit of analysis, allowing for the fact that teeth and surfaces within the same individual must be considered non-independent.

RESULTS

When aggregated data were used, point estimates were larger in some instances. The precision of the estimates increased considerably when the tooth as compared to the individual was used as the unit of analysis. No or limited gain in precision was obtained when the tooth surface as compared to the tooth was used as unit of analysis.

CONCLUSIONS

The choice of unit of analysis may strongly influence the result of the statistical analyses and thus the conclusion of an investigation.

Influence of dental restorative materials on salivary Streptococcus mutans and lactobacilli in the primary dentition

PURPOSE

When restoring deciduous teeth with extensive lesions, preformed stainless steel crowns are increasingly used in addition to resin-based materials. The aim of the present clinical study was to examine the influence of composites and stainless steel crowns on the cariogenic bacteria S. mutans and Lactobacilli by means of a commercially available salivary test (CRT bacteria) in 100 children.

MATERIALS AND METHODS

For 50 children (30 boys, 20 girls, mean age 5.7 +/- 2.4 years) only composites have been used as a restorative material (an average of 9 fillings per child, total number: n=450), which had been in situ for an average of 15.9 months at the time of the examination. In another group of 50 children (33 boys, 17 girls, mean age 5.9 +/- 2.5 years), stainless steel crowns and composites have been used for restorations (an average of 3.5 stainless steel crowns per child, total number: n=174, an average of 7 composite fillings per child, total number n=348), which had been in place for a mean period of 17.2 months.

RESULTS

The salivary examination of the children with composite restorations showed a high proportion of patients (64%, n=32) with high numbers (> or = 10(5)) of S. mutans and Lactobacilli (54%, n=27). Only 22% (n=11) of the children with additional stainless steel crown restorations were found to have high numbers (> or = 10(5)) of S. mutans and Lactobacilli (34%, n=17).

CONCLUSION

This study shows a potential positive inhibitory effect of stainless steel crown restorations as compared to composite fillings with respect to the oral bacterial colonization.

Evaluation of clinical and microbiological features of deep carious lesions in primary molars

PURPOSE

Concern about the survival of microorganisms in deep carious lesions may often lead to unnecessary exposure of the pulp during excavation. This study evaluated the relationship between microbiological and clinical results of deep carious lesions in primary molars.

METHODS

Clinical evaluation was performed on 72 deep carious lesions considered to have pulp perforation after traditional excavation. The dentin color and consistency were assessed by means of standardized scales using the technique of Bjorndal et al before restoration. For microbiological examination, dentin samples were taken by a sterile bur and transferred to transport fluid, then plated on tryptic soy agar for growth of total colony forming units. Samples werethen transferred on Rogosa SL agar for growth of oral lactobacilli and on mitis salivarius agar for growth of mutans streptococci.

RESULTS

The proportion of mutans streptococci, lactobacilli, and total colony forming units increased when the dentin color and consistency increased. However, the proportion of lactobacilli was smaller than that of mutans streptococci in carious dentin samples.

CONCLUSIONS

Contrary to expectations, the findings showed that the number of bacteria in carious dentin of primary molars was not significantly excessive.

Initial acquisition and transmission of mutans streptococci in children at day nursery

The purposes of this study were to determine the age at the initial acquisition of mutans streptococci (MS) and to determine the transmission of MS among children at day nursery by describing the occurrence of genotypes prepared by chromosomal DNA fingerprinting of the bacteria using restriction endonuclease EcoRI and HaeIII. The samples were 39 children (23 boys and 16 girls) aged 0-5 years old, 14 pairs of parents and 6 nursery caretakers of a day nursery in Hiroshima city, Japan. The children had no dental caries throughout the experiment. Plaque samples of the children were taken using toothbrushes at 1 month intervals for 30 months. The initial acquisition of MS occurred between the ages of 8 months and 52 months with a mean age of 24.2 months. The cumulative probability of initial acquisition of MS increased rapidly at the age of 12 to 25 months after 10 to 20 primary teeth had erupted. Transmission of MS was found between child and mother (33.3%), child and father (8.3%) and child and others including amongst the children (58.4%), but no evidence of MS transmission from nursery caretakers was found. Two children acquired MS from intra- and extra-familial transmission. This study suggests that the child's environment also plays a role in the initial acquisition and transmission of MS, in addition to the oral condition of the children.

Preventing the transfer of Streptococcus mutans from primary molars to permanent first molars using chlorhexidine

PURPOSE

The purpose of this study was to determine if the application of 1% chlorhexidine-containing wax on primary molars during the period of eruption of the first permanent molars could prevent the transfer of certain oral flora, namely Streptococcus mutans, to the permanent molars.

METHODS

Fourteen children with a mean age of 6.5 years (7 males and 7 females) were assigned into two groups: a chlorhexidine group (n=9) in which 1% chlorhexidine-containing wax was painted on primary molars on one side of the mouth; and a placebo wax group (n=5) in which a similar wax, but without chlorhexidine, was painted on primary molars on the other side of the mouth. Baseline saliva samples and pooled plaque samples from the primary molars on both sides of the dentition were obtained from the two treatment groups. Following treatment, plaque samples from the occlusal fissures of the first permanent molars on both sides of the dentition were obtained. The levels of S.mutans and other members of the oral flora on the treated sides (chlorhexidine or placebo) were compared with those on the untreated sides.

RESULTS

The results showed that the proportions of S.mutans to S.sanguinis were significantly lower in the chlorhexidine-treated sides compared to the untreated (P=0.04) and in the chlorhexidine-treated patients compared to placebo (P=0.029).

CONCLUSIONS

Since lower mutans to sanguinis ratios have been associated with lower caries experience, treating primary molars with 1% chlorhexidine wax during eruption of permanent first molars may be a simple means for shifting the fissure flora of the permanent molars towards a more favorable balance.

Periodontopathic bacterial infection in childhood

BACKGROUND

Little information is available on periodontopathic bacterial infection in childhood. We assessed the prevalence by age of 10 putative periodontopathic microorganisms in periodontally healthy children using a polymerase chain reaction (PCR) assay.

METHODS

Plaque samples were collected from the buccal-mesial sulcus of the first molar or second primary molar in the right upper quadrant of 144 children (2 to 13 years old, 12 subjects from each year of age) who showed negligible periodontal inflammation. Using species-specific primers of Porphyromonas gingivalis, Bacteroides forsythus, Prevotella intermedia, Prevotella nigrescens, Campylobacter rectus, Eikenella corrodens, Actinobacillus actinomycetemcomitans, Capnocytophaga ochracea, Capnocytophaga sputigena, and Treponema denticola, PCR amplification was performed with bacterial genomic DNA from plaque samples.

RESULTS

The results indicated that C. rectus, E. corrodens, A. actinomycetemcomitans, C. ochracea, and C. sputigena were found in about 50% of the plaque samples from all age groups, while B. forsythus and P. intermedia were detected less frequently, and P. gingivalis and T. denticola were not found. In contrast, the percentage of P. nigrescens-positive subjects increased with age in primary dentition, and reached about 50% at 7 years of age and older. Subject-based analyses suggested that the number of bacterial species in the plaque samples increased gradually with age until 5 years old, and then reached a plateau after the mixed dentition period.

CONCLUSIONS

The colonization of many putative periodontopathic microorganisms can occur quite early in childhood without clinical signs of periodontal disease. However, colonization by P. gingivalis and T. denticola was not detected in periodontally healthy children.