Dental black plaque: metagenomic characterization and comparative analysis with white-plaque.

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.

Raising awareness about microbial antibiotic resistance in undergraduate dental students: a research-based strategy for teaching non-laboratory elements of a microbiology curriculum.

BACKGROUND: Resistance to antimicrobial agents has become a problem in modern society. Antibiotic resistant bacteria undermine the prevention and treatment of infections. Undergraduate dental students in Europe are required to receive information in aspects of microbiology relevant for dental practice, including oral microbial pathogens and resistance mechanisms against antimicrobial compounds. The objective of this study was to implement a research-based strategy to aid the understanding of the increase in antimicrobial resistance in undergraduate dental student training. The primary outcome of this project is the efficacious delivery of the learning objectives. METHODS: Ten volunteer undergraduate student "ambassadors" were recruited to manage the project with assistance from lead academics. Student ambassadors were a source of peer learning for their colleagues. The project consisted of three phases: Pre-project preparation (in which the ambassadors received special instruction and training); Practical experience (in which the ambassadors worked with volunteer student colleagues to carry out the project); Public presentation of results (in which ambassadors presented study results at a scientific conference of their choosing). RESULTS: A total of 1164 students volunteered for the project, corresponding to an average participation rate of 76.4% students per year of the course. Following final debriefing, student participants and ambassadors were strongly positive in their evaluation of the achievement of 8 key student learning objectives. The results demonstrate that most volunteers improved their knowledge related to antimicrobial resistance mechanisms in microbiology. Additional benefits of participation in this project included an improvement in dental knowledge and ethics in biomedical research for the student volunteers, whilst the student ambassadors reported improved knowledge about critical thinking and study design, as well as a deeper understanding about microbiological analysis methods. CONCLUSIONS: To the best of our knowledge, this the first instance of the application of project-based methodologies to the teaching of a traditionally non-laboratory component of a subject taught in the dentistry curriculum. Results from both students and ambassadors highlighted the increase in dental knowledge and an increased awareness of antimicrobial resistance as the key outcomes of this project.

Does Psychological Profile Influence Third Molar Extraction and Postoperative Pain?

PURPOSE: Our purposes were to determine the influence of psychological profile on hemodynamic changes in patients who undergo surgical removal of the third molars under intravenous sedation and to evaluate the effect on patients' anxiety and postoperative recovery. PATIENTS AND METHODS: We performed a prospective study of 100 patients (American Society of Anesthesiologists classes I and II; aged ≥18 years) seen in the CIMIVClinic (Department of Oral Surgery, Casa de Salud University Hospital, Valencia, Spain) who underwent extractions of all third molars under intravenous sedation. All patients were administered the Symptom Checklist 90 Revised (SCL-90-R). The following parameters were monitored at different times during the surgical interventions: systolic blood pressure, diastolic blood pressure, oxygen saturation, and heart rate. Position and depth of impaction of the tooth (Pell and Gregory classification and Winter classification), surgery duration, and surgical technique also were recorded. Finally, the degree of pain experienced the week after the surgical intervention was measured using a visual analog scale. RESULTS: Patients' anxiety levels preoperatively were significantly higher in patients with psychological distress (P = .023). Postoperative pain significantly decreased from the first day to the seventh day in healthy patients but not in patients with altered psychological conditions (P < .05). Nevertheless, the hemodynamic changes were not correlated with the psychological impairment. CONCLUSIONS: Intravenous sedation enables the control of hemodynamic changes in all patients independently of their psychological profile. Patients with psychological distress present with higher levels of dental anxiety and postoperative pain. Future studies are needed to further clarify this interaction.

Effects of Collagen Resorbable Membrane Placement After the Surgical Extraction of Impacted Lower Third Molars.

PURPOSE: The use of resorbable collagen membranes (RMs) in the treatment of intraosseous defects and deep periodontal pockets on the distal side of a lower second molar (L2M) after surgical extraction of an impacted lower third molar (L3M) has shown contradictory results. This study evaluated the effects of RM placement on the healing of a bone defect distal to an L2M after surgical extraction of a horizontal or mesioangular impacted L3M. PATIENTS AND METHODS: A parallel-group randomized controlled trial with 2 independent groups of 30 patients requiring surgical extraction of an L3M was carried out. After extraction, patients received an RM (Bio-Gide, Geistlich Pharma AG, Wolhusen, Switzerland) or only suture. At the initial checkup and during postoperative monitoring at 1, 3, and 6 months, the distal vestibular, distal, and distolingual probing depths and distal vestibular attachment level of the L2M were measured. RESULTS: Age (control group, 33.8 ± 6.9 yr; guided tissue regeneration group, 35.6 ± 6.3 yr; P = .322) and the number of women (control group, 15 of 29; guided tissue regeneration group, 14 of 27; P = .992) were similar in the 2 groups. The distal vestibular, distal, and distolingual probing depths of the L2M, distal vestibular attachment level, distance from the cementoenamel junction, and distance from the alveolar crest to the base of the defect showed greater improvement 6 months after surgical extraction in the RM group (P < .05). CONCLUSIONS: The use of RMs after surgical extraction of mesioangular or horizontally impacted L3Ms stimulates bone regeneration, improving the attachment level and bone fill distal to the L2M. Likewise, it decreases the distal probing depth and results in faster recovery. RM placement after surgical extraction of an impacted L3M is recommended because it prevents periodontal defects after L3M surgery.

Lowering of the mouth floor and vestibuloplasty to support a mandibular overdenture retained by two implants. A case report.

In Oral Implantology most of the procedures are predictable and have high success rates. The use of osseointegrated implants as a therapeutic option for the rehabilitation of patients with severe mandibular atrophy has decreased the need for pre-prosthetic surgery Nevertheless, complications may occur during implant surgery and also once the prosthesis has been placed. This paper describes the case of a totally edentulous patient with an upper complete removable denture and an implant-retained overdenture with two implants in the intermentonian region. During clinical examination, the implant abutments were totally covered by soft tissue since the floor of the mouth was elevated. The panoramic radiography showed severe mandibular atrophy. Vestibuloplasty was performed together with the lowering of the floor of the mouth under general anesthesia and nasotracheal intubation to expose the implants. A new prosthesis was fabricated for the patient to prevent recurrence and improve the patient's chewing ability as it formed a physical barrier against soft tissue migration on prosthetic attachments. Key words:Vestibuloplasty, lowering of the mouth floor, complications in oral implantology.

Antibiotic prescription in the treatment of odontogenic infection by health professionals: a factor to consensus.

OBJECTIVE: To observe the attitude of dentists and family doctors in prescribing antibiotics for the treatment of dental infections. STUDY DESIGN: A poll was performed to determine the differences in the prescription of antibiotics for the treatment of odontogenic infection by dentists and family doctors of the primary care department of the Catalan Health Care Service. RESULTS: A hundred polls were distributed among family doctors, and another 100 ones among primary care dentists assigned to the Catalan Health Care Service of the Generalitat de Catalunya. Of the total of questionnaires distributed, 63 were retuned and answered from dentists and 71 from family doctors. Eighty-one percent of dentists included in the opinion poll considered amoxicillin as the first antibiotic choice for the treatment of odontogenic infections, while 73.2% of family doctors preferred the combination of amoxicillin and clavulanic acid. With regard to antibiotics of choice in patients allergic to penicillin, 67.7% of family doctors preferred macrolides (25.4% opted for clarithromycin, 25.4% for erythromycin and 16.9% for spiramycin). However, clindamycin was the antibiotic most frequently prescribed by dentists (66.7%), followed by erythromycin (28.6%). CONCLUSIONS: The results of this study show a large discrepancy in the criteria for the treatment of odontogenic infections on the part of leading professionals involved in the management of this condition. Although the most common prescription involved beta-lactam antibiotics in both groups, several significant differences have been detected with regard to the second antibiotic choice.

Validation of a computer-assisted system on classifying lower third molars

Objectives: The present study evaluates the reliability of the Radio Memory® software (Radio Memory; Belo Horizonte,Brasil.) on classifying lower third molars, analyzing intra- and interexaminer agreement of the results. Study Design: An observational, descriptive study of 280 lower third molars was made. The corresponding orthopantomographs were analyzed by two examiners using the Radio Memory® software. The exam was repeated 30 days after the first observation by each examiner. Both intra- and interexaminer agreement were determined usingthe SPSS v 12.0 software package for Windows (SPSS; Chicago, USA). Results: Intra- and interexaminer agreement was shown for both the Pell & Gregory and the Winter classifications,p<0.01, with 99% significant correlation between variables in all the cases. Conclusions: The use of Radio Memory® software for the classification of lower third molars is shown to be avalid alternative to the conventional method (direct evaluation on the orthopantomograph), for both clinical andinvestigational applications (AU)

Validation of a computer-assisted system on classifying lower third molars.

OBJECTIVES: The present study evaluates the reliability of the Radio Memory® software (Radio Memory; Belo Horizonte, Brasil.) on classifying lower third molars, analyzing intra- and interexaminer agreement of the results. STUDY DESIGN: An observational, descriptive study of 280 lower third molars was made. The corresponding orthopantomographs were analyzed by two examiners using the Radio Memory® software. The exam was repeated 30 days after the first observation by each examiner. Both intra- and interexaminer agreement were determined using the SPSS v 12.0 software package for Windows (SPSS; Chicago, USA). RESULTS: Intra- and interexaminer agreement was shown for both the Pell & Gregory and the Winter classifications, p<0.01, with 99% significant correlation between variables in all the cases. CONCLUSIONS: The use of Radio Memory® software for the classification of lower third molars is shown to be a valid alternative to the conventional method (direct evaluation on the orthopantomograph), for both clinical and investigational applications.

Traumatic bone cyst: A retrospective study of 21 cases

Objective: To describe the clinical and radiological characteristics, and surgical findings of traumatic bone cysts. Study Design: A retrospective observational study was made of 21 traumatic bone cysts. The diagnosis was based on the anamnesis, clinical examination, and complementary tests. Panoramic and periapical X-rays were obtained in all cases, together with computed tomography as decided by the surgeon. A descriptive statistical analysis was made of the study variables using the SPSS v12.0 for Windows. Results: There was a clear female predominance (14:7). The mean age was 26.5 years (range 8-45 years). The cysts in all cases constituted casual findings during routine radiological exploration. In those cases where computed tomographic images were available, preservation of the vestibular and lingual cortical layers was observed. Five of the 21 patients (23.8%) reported a clear antecedent of traumatism in the affected zone. All the lesions were subjected to surgery, and the cavities were found to be vacant in 90.5% of the cases. In only two patients were vascular contents seen within the cavity. Two of the patients presented postoperative paresthesia of the inferior dental nerve that subsided within two weeks. The 19 patients in whom adequate postoperative follow-up proved possible all showed complete bone healing. Conclusions: Traumatic bone cysts were a casual finding. During the surgery, most cases showed to be vacant cavity without an ephitelial lining. Careful curettage of the lesion favors progressive bone regeneration, offering a good prognosis and an almost negligible relapse rate. Other treatment options only would be justified in cases of relapse (AU)

Traumatic bone cyst: a retrospective study of 21 cases.

OBJECTIVE: To describe the clinical and radiological characteristics, and surgical findings of traumatic bone cysts. STUDY DESIGN: A retrospective observational study was made of 21 traumatic bone cysts. The diagnosis was based on the anamnesis, clinical exploration, and complementary tests. Panoramic and periapical X-rays were obtained in all cases, together with computed tomography as decided by the surgeon. A descriptive statistical analysis was made of the study variables using the SPSS v12.0 for Windows. RESULTS: There was a clear female predominance (14:7). The mean age was 26.5 years (range 8-45 years). The cysts in all cases constituted casual findings during routine radiological exploration. In those cases where computed tomographic images were available, preservation of the vestibular and lingual cortical layers was observed. Five of the 21 patients (23.8%) reported a clear antecedent of traumatism in the affected zone. All the lesions were subjected to surgery, and the cavities were found to be vacant in 90.5% of the cases. In only two patients were vascular contents seen within the cavity. Two of the patients presented postoperative paresthesia of the inferior dental nerve that subsided within two weeks. The 19 patients in whom adequate postoperative follow-up proved possible all showed complete bone healing. CONCLUSIONS: Traumatic bone cysts were a casual finding. During the surgery, most cases showed to be vacant cavity without an ephitelial lining. Careful curettage of the lesion favors progressive bone regeneration, offering a good prognosis and an almost negligible relapse rate. Other treatment options only would be justified in cases of relapse.