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Biomedical subjects

Larz Spångberg

Publications and source records attributed to Larz Spångberg.

3 recordsLinked to original sources
PubMed2005

Enterococcus spp. in endodontically treated teeth with and without periradicular lesions.

The purpose of this study was to determine if Enterococcus spp. are more prevalent in endodontically treated teeth with periradicular lesions compared with teeth that require retreatment but have no periradicular rarefaction. Fifty-eight teeth that had received root canal therapy more than 1 yr previously and required retreatment were included. Designation of lesion versus no lesion was determined by two experienced endodontists. DNA extraction and PCR amplification were performed using ubiquitous 16S rDNA bacterial primers, as well as Enterococcus spp.-specific primers. The results showed that the overall prevalence of bacteria was 90% and Enterococcus spp. was 12%. chi analysis revealed a statistically significant relationship between the presence of a lesion and the presence of bacteria, as detected by the universal primers (p = 0.032). Using logistic regression, a statistically significant relationship was found between teeth with normal periapex and the presence of Enterococcus spp. (p = 0.023). This study revealed that bacteria are significantly associated with endodontic treatment failure but enterococci are not associated with disease.

Adult↗
PubMed2004

Chlorhexidine substantivity in root canal dentin.

OBJECTIVE: The purpose of this investigation was to evaluate the substantivity of chlorhexidine (CHX) within a root canal system and to assess how long the CHX remains antimicrobially effective. STUDY DESIGN: Bovine roots were sectioned and standardized to 8 mm. Sections, which served as controls, were treated with 1% sodium hypochlorite and 1 mol/L EDTA, then obturated with gutta percha and AH26 sealer. Experimental sections were treated similarly except they were placed in 2% CHX for 10 minutes prior to obturation. Control specimens were divided into 4 control groups and stored in saline for 1 day, 3 weeks, 6 weeks, and 12 weeks. Experimental specimens were divided into 4 groups and stored in saline for 1 day, 3 weeks, 6 weeks, and 12 weeks. After their respective storage periods, all specimens were halved and canal wall dentin was ground out with Peeso reamers. Dentin specimens were agitated in 700 microl of saline for 5 hours to release CHX. After centrifugation the supernatants were analyzed with UV spectrophotometry at 253 nm. To determine whether the CHX from dentin samples remained antimicrobial, the extracts from experimental and control groups were mixed with cultures of Enterococcus faecalis. RESULTS: After 1 day of storage, the dentin extract contained approximately 0.0048% CHX. After 3, 6 and 12 weeks, dentin extracts contained approximately 0.0023%, 0.0016%, and 0.0010% CHX respectively. Extracts from the storage groups were found to be highly antimicrobial corresponding to the CHX concentration. CONCLUSION: The results of this study indicate that CHX is retained in root canal dentin in antimicrobially effective amounts for up to 12 weeks.

Animals↗