Dpto. Odontología

Background: Orthodontic treatment with fixed appliances is associated with changes in oral microbiota, including increased Candida colonization. The Candida fungus can cause oral lesions and infections such as candidiasis and angular cheilitis, and is harmful to both the patient and the orthodontist. Poor hygiene facilitates the colonization of these microorganisms. The key aim was to quantify the colonization of C. albicans in patients prior to beginning orthodontic treatment, and during the treatment process. Material and Methods: A total of 124 patients (43 males and 80 females) with a mean age of 19.5 years, who required treatment with metal or aesthetic (ceramic) braces, were studied. Microbiological samples were taken from the oral cavity using the swab technique throughout the treatment and cultured on a Sabouraud Dextrose Agar plate and, if positive, cultured on a CHROMagar® Candida plate. Results: In contrast to other published studies, no statistically significant increase in C. albicans colonization was observed during the orthodontic treatment. The fixed appliances had no influence on the presence, absence or level of colonization by C. albicans and there were no significant differences between the different appliances studied. Conclusions: Our study showed that frequency of oral hygiene measures by study participants did not affect the rate of oral carriage of Candida in a statistically significant manner. This observation contrasted with published literature, which suggests that thorough brushing is important to prevent the build-up of Candida species.

Extrinsic black dental staining is an external dental discoloration of bacterial origin, considered a special form of dental plaque. Currently, there is no definitive therapeutic option for eliminating black stain. This study employed 16S rRNA metagenomics to analyze black stain and white-plaque samples from 27 adult volunteers. Study objectives were to: describe the microbial diversity of adult black stain samples; characterize their taxonomic profile; compare the microbiomes of black stain versus white-plaque from adult volunteers and propose a functional map of the black stain microbiome using PICRUSt2. The black stain microbiome was poorer in species diversity as compared to white-plaque. The five most abundant genera in black stain were Capnocytophaga, Leptotrichia, Fusobacterium, Corynebacterium and Streptococcus. Functional analysis of microbial species revealed conserved and consistent clustering of functional pathways within and between black stain and white-plaque microbiomes. We describe enrichment of heme biosynthetic pathways in black stain. Our results suggest that the dysbiosis in black stain resembles “orally healthy” communities. The increased abundance of heme biosynthetic pathways suggests that heme-dependent iron sequestration and subsequent metabolism are key for black stain formation. Further research should decipher the regulation of heme biosynthetic genes and characterize the temporal sequence leading to colonization and dysbiosis.

INTRODUCTION AND AIMS: This study investigates the effects of the application of antimicrobial phototherapy on black-stained tooth surfaces. Key variables were area, color and time taken to reappearance of black stain following dental prophylaxis with and without antimicrobial phototherapy. Differences in bacterial composition of black stain (specifically Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivalis) were analyzed. MATERIAL AND METHODS: The phototherapy device used was GLO™ Science LLC, New York, America, emitting light at 475 nm and a power of 3W. Light was applied in 2 cycles of 8 min on 31 volunteers. Microbial identification was carried out on DNA extracted from black plaque. This study is registered with ClinicalTrials.gov, number NCT03309748. RESULTS: Following antimicrobial phototherapy, 64.5% of patients displayed reduced pigmentation area. Plaque color was lighter in 48.4% of subjects. Pigmentation area and depth of color returned to normal levels during the course of the study. Colonization by the three bacterial species decreased, although the changes were not statistically significant. We report a key novel finding showing elevated levels of colonization by Tannerella forsythia (83.9%) in adult black stain. CONCLUSIONS: Application of phototherapy results in a reduction in area, color and bacterial colonization of black plaque in adults. The changes were not found to be statistically significant, perhaps owing to the low illumination power of the homewhitening device. For the first time, we document the elevated presence of Tannerella forsythia in adult black stain. We also demonstrate the potential application of a commercially available home-whitening device for black plaque treatment.

Objective: Dens evaginatus (DE) is an odontogenic developmental anomaly that can be defined as a supernumerary tubercle structure that extends from the occlusal surface of the affected tooth. Tubercular fracture or attrition of the tubercle, invaded by pulp tissue, may cause various pulpal diseases, such as pulpitis, pulp necrosis, and periapical periodontitis. This study aimed to determine the prevalence of premolars with DE in Taiwanese and Spanish study populations and to report associated dental complications. Methods: This study was based on the clinical examination of volunteers of Spanish and Taiwanese origin, recruited among the undergraduate dentistry students at CEU-Cardenal Herrera University, Valencia, Spain. Informed consents were obtained from students identified with DE. Additional examinations were performed, including vitality test, percussion, palpation, and radiographs, to diagnosis the status of the pulp and periapical tissue. Results: The prevalence of DE among Taiwanese students was 4.08%, compared to 0% in the Spanish Caucasian group. In the Taiwanese group, the occurrence of DE in premolars was more common in the mandibular (78.9%) compared to the maxillar region (21.1%). In 84% of the cases, DE-affected teeth were found bilaterally. The mandibular second premolar was the most commonly involved tooth (57.8%). When investigating the complications related to DE among six affected Taiwanese students, it was found that two teeth (10.5%) had received pulp treatment, one of them prior to complete root formation. Conclusion: DE appears to be more prevalent in people of Mongoloid origin and rare in those of Caucasian origin. The wear or fracture of DE may affect pulpal tissue, leading to incomplete root growth.