Hypophosphatasia: Evaluation of Size and Mineral Density of Exfoliated Teeth.

OBJECTIVE: Most cases of hypophosphatasia (HPP) exhibit early loss of primary teeth. Results of micro-computed tomography (micro-CT) analysis of teeth with HPP have not yet been reported. The purpose of the present study was to describe the size and mineral density distribution and mapping of exfoliated teeth with HPP using micro CT. STUDY DESIGN: Seven exfoliated teeth were obtained from a patient with HPP. Exfoliated teeth sizes were measured on micro CT images and mineral densities of the mandibular primary central incisors were determined. RESULTS: Partial dentures were fabricated for the patient to replace the eight primary teeth which had exfoliated. Most primary teeth sizes were within the normal range. The mean values of enamel and dentin mineral densities in teeth with HPP were 1.35 and 0.88 g/cm3, respectively, in the mandibular primary central incisors. CONCLUSION: Mineral density distribution and mapping revealed that the values in teeth with HPP were lower than the homonymous teeth controls in all regions from the crown to apex. Furthermore, it was demonstrated that the differences between HPP and controls were larger on the crown side and the differences tended to converge on the apex side. These results suggested that the present patient showed mild hypomineralization in the primary dentition.

Self-Esteem and Oral Condition of Institutionalized Abused Children in Japan.

OBJECTIVE: Abused children have been reported to have low self-esteem. The aim of this study was to investigate the effects of dental intervention on self-esteem, oral condition, and concern for oral health in abused children admitted to a child protection service facility. STUDY DESIGN: We examined the oral condition of 65 children (34 boys, 31 girls; aged 2-15 years), instructed them in tooth-brushing. Self-esteem was examined using Pope's five-scale test for children. Before discharge, the children completed questionnaires on concern about their oral health. RESULTS: The findings revealed the reasons for admission were child abuse and neglect (n=45), domestic violence against the mother (n= 20), special needs (n=11), delinquency (n=7), school refusal (n=2), and other reasons (n=3). Thirty-five of the 65 residents (54%) needed treatment for caries. Of these, 24 (69%) were abused children and 11 (31%) were admitted due to other reasons. Mean self-esteem score differed significantly between the resident children (n=43) and an outpatient control group (n=102) (59.16±14.54 vs 73.92±16.81, respectively; p<0.01). CONCLUSION: Although the abused children had low self-esteem, after dental intervention, positive answers regarding oral health were obtained. The findings suggest that dental interventions might be effective for helping to improve the self-esteem of abused children.

Host beta-globin gene fragments in crevicular fluid as a biomarker in periodontal health and disease.

BACKGROUND AND OBJECTIVE: Leukocytes and epithelium are the first line of defense in preventing bacterial invasion into periodontium. Some of these cells die in gingival crevicular fluid, whereupon their DNA is spilled out. The present study was designed to investigate the profile of host beta-globin gene fragments in the gingival crevicular fluid of various periodontal conditions. MATERIAL AND METHODS: Gingival crevicular fluid from 40 teeth with chronic periodontitis, 30 with gingivitis and 22 that were clinically healthy were centrifuged (3,000 g, 10 min). The supernatant (cell-free gingival crevicular fluid) was centrifuged again (13,000 g, 10 min), resulting in the pellet and the supernatant as debris and debris-free fractions, respectively. Specific primers for amplifying 110 bp, 536 bp and 2 kb amplicons of human beta-globin gene were used to investigate host DNA by quantitative and qualitative polymerase chain reaction. RESULTS: The periodontitis group showed the largest amount of host beta-globin gene fragments, while the healthy group had the lowest. In the debris and debris-free fractions, the 536 bp and 2 kb amplicons were more often detected in the periodontitis group than in the other groups. Interestingly, the presence of 2 kb amplicon in the debris fraction could be used to discriminate periodontitis from gingivitis and healthy groups because we found it in 85% of periodontitis samples but only in 13% of gingivitis samples, and it was absent in the healthy group. CONCLUSION: This study shows the different DNA profiles of cell-free gingival crevicular fluid in periodontal health and disease. It suggests that the quantity and quality of host DNA are dependent on the disease conditions. Therefore, the beta-globin gene fragments in cell-free gingival crevicular fluid may be a potential biomarker of periodontal disease progression.

Differentiation of oral Actinomyces species by 16S ribosomal DNA polymerase chain reaction-restriction fragment length polymorphism.

16S rDNA polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to generate restriction profiles of the reference strains, including the American Type Culture Collection type strains, of oral Actinomyces spp., i.e., A. israelii, A. gerencseriae, A. naeslundii genospecies 1 and 2, A. odontolyticus, A. meyeri and A. georgiae, and 23 Actinomyces strains isolated from human dental plaque. The 16S rRNA gene sequences from isolated genomic DNA samples were amplified by PCR. The PCR products were purified and characterized by single digestion with four restriction endonucleases, i.e., MnlI, HaeIII, CfoI, or HpaII. Among them, MnlI was found to discriminate the respective reference strains. The clinical isolates were assigned to one of the species, i.e., A. gerencseriae, A. naeslundii genospecies 1 and 2 and A. odontolyticus, on the basis of their restriction profiles by single digestion with MnlI. Thus, 16S rDNA PCR-RFLP, using MnlI, is a rapid and reliable method for the differentiation of oral Actinomyces spp.

[Clinico-statistical observation of the dental surgery in the pedodontics clinic of Niigata University Dental Hospital during the period from 1979 to 1989].

Clinico-statistical observation was performed on the dental surgery in the Pedodontic Clinic of Niigata University Dental Hospital during the period from August 1979 to September 1989. 1. The number of surgical operations amounted to 656 cases (males 384 and female 272) and the highest age incidence was in the 6-8 year old range. 2. The incidence of the impacted teeth (62.8%) and the abnormality of the frenum (22.8%) occupied over 85% of all the cases. 3. Based on sex, the impacted supernumerary teeth and the abnormality of the buccal frenum, odotoma were more frequent in males, while the abnormality of the upper frenum and the mucous cysts were more frequent in females. 4. About 40% of the operative patients accepted were introduced from other medical institutions. 5. Regarding the methods of surgery, the impacted permanent teeth were frequent revealed by surgical exposure, while the diseases of salivary glands were revealed by extirpation. The benign tumors were removed by extirpation, the diseases of soft tissues by excision, cysts in the jaws were all surgically removed by marsupialization. 6. In regard to the age at the time of the operation, the abnormal frenum were often seen under 4 years of age but large increases were found in the impacted teeth from 4 to 8 years of age. The diseases of salivary glands and of soft tissues were seen more frequently under 10 years of age, and cysts in the jaws were noted after 7 years of age. 7. Children undergoing surgery who suffered from general diseases amounted to 31 cases and were found most commonly in cases of nervous mental diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Nested PCR for detection of mutans streptococci in dental plaque.

AIMS: Mutans streptococci such as Streptococcus mutans and Streptococcus sobrinus have been implicated in human dental caries. In an attempt to develop a rapid and sensitive method for detecting Strep. mutans and Strep. sobrinus in dental plaque, a nested PCR amplification based on the 16S rRNA gene was employed. METHODS AND RESULTS: A universal set of PCR primers for bacterial 16S rRNA gene was introduced for the first PCR, and then two sets of primers specific for the 16S rRNA gene sequences of either Strep. mutans or Strep. sobrinus were used for the second PCR. Eighteen plaque samples were analyzed, and a nested PCR was shown to be more sensitive for detecting Strep. mutans and Strep. sobrinus than direct PCR. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The 16S rRNA gene-based nested PCR method is a rapid and sensitive method for the detection of mutans streptococci, and may also be suitable for carrying out large-scale studies on the cariogenicity of mutans streptococci.

Fermentation of five sucrose isomers by human dental plaque bacteria.

Sucrose has five structural isomers: palatinose, trehalulose, turanose, maltulose and leucrose. Although these isomers have been reported to be noncariogenic disaccharides, which cannot be utilized by mutans streptococci, there is no information about their fermentability by other bacteria in dental plaque. The purpose of the present study was to examine whether these isomers were fermented by predominant bacteria in human dental plaque. Clinical bacterial isolates obtained from dental plaque from 3 children aged 22 months to 50 months (146 strains) were inoculated into 3 ml of peptone-yeast extract (PY medium) containing glucose for 1 day, then an aliquot of 20 microl of culture medium was inoculated into 1 ml of PY medium containing 1% (w/v) of the respective test carbohydrates. After incubation for 1 day, the pH values and the optical density at 660 nm of the cultures were measured. Fermentation ability was measured by pH or=0.5. Of the clinical isolates, 33% fermented palatinose, and 69% of these were Actinomyces species. All of the palatinose-fermenting bacterial strains fermented trehalulose, 25% fermented turanose, 70% fermented maltulose and 23% fermented leucrose. We therefore conclude that, in human dental plaque, there are significant numbers of bacteria that are able to ferment sucrose isomers.

Identification of mutans streptococci by restriction fragment length polymorphism analysis of polymerase chain reaction-amplified 16S ribosomal RNA genes.

Mutans streptococci are frequently isolated from dental plaque and carious lesions. These bacteria have been identified by conventional methods such as biochemical and serologic tests followed by the isolation of colonies on the mitis-salivarius agar, which are sometimes inconsistent. Recently, species-specific polymerase chain reaction (PCR) has been reported to rapidly identify Streptococcus mutans and Streptococcus sobrinus. However, in the case of identification and classification into several species, e.g. within the group of mutans streptococci consisting of seven species, the identification using species-specific PCR seems somewhat inefficient because of need for the development and preparation of specific primers for each species. Therefore, in this study we developed a simple method using restriction fragment length polymorphism analysis of PCR-amplified 16S ribosomal RNA genes (16S rRNA genes PCR-RFLP) for the identification of seven different species included in the group of mutans streptococci. We amplified 16S rRNA gene sequences from genomic DNA samples by PCR using universal primers and digested the PCR products with the restriction endonucleases, HpaII and HaeIII. HpaII produced six RFLP patterns for eight reference strains, since the patterns for S. sobrinus, Streptococcus downei and Streptococcus ferus were similar. RFLP patterns produced with HaeIII could separate these three species. Furthermore, the RFLP patterns predicted from the 16S rRNA gene sequences in the GenBank database agreed with the actual RFLP patterns produced in the present study. The 16S rRNA sequence comparisons can be used to identify oral mutans streptococci; however, the identification by sequencing is sometimes difficult in large-scale studies and for small laboratories. Therefore, 16S rRNA genes PCR-RFLP, using HpaII and HaeIII, could be an alternative method for the identification of mutans streptococci, and may be applicable for large-scale studies on the cariogenicity of mutans streptococci.