Biomechanical behavior of weakened roots restored with custom-made post-and-cores of glass fiber and polyetheretherketone.

PURPOSE: To evaluate the influence of post type and mechanical aging on compression force resistance, fracture pattern, and stress distribution in weakened roots. MATERIALS AND METHODS: Bovine roots were endodontically treated and widened-and randomly divided into 8 groups (n = 10) according to post type (prefabricated glass fiber post and customized anatomic glass fiber post, milled glass fiber post-and-core, and milled polyetheretherketone post-and-core) and mechanical aging (without and with mechanical aging). Three hundred thousand cycles of mechanical fatigue were performed and compression force resistance (N) was analyzed by two-way ANOVA and Tukey test (α = 0.05). Fracture patterns were reported and stress distribution was analyzed by finite elements analysis. RESULTS: There was a significant effect of post type (p = 0.032) and mechanical aging (p = 0.009), but no double interaction (p = 0.879). Higher values were recorded in the milled glass fiber and polyetheretherketone post-and-core groups compared to the prefabricated glass fiber post groups, and no significant difference was found among anatomic glass fiber post groups and other groups. Reparable fractures were predominant in the milled glass fiber and polyetheretherketone post-and-core groups. Prefabricated glass fiber posts and milled polyetheretherketone post-and-cores showed similar stress distribution. CONCLUSIONS: Post type and mechanical aging influence the compression force resistance and fracture pattern of weakened roots. Milled glass fiber and polyetheretherketone post-and-cores exhibited higher compression force resistance and more reparable fractures compared to prefabricated glass fiber posts. Prefabricated glass fiber posts and milled polyetheretherketone post-and-cores showed similar stress distribution.

Chemomechanical preparation influences the microbial community and the levels of LPS, LTA and cytokines in combined endodontic-periodontal lesions: A clinical study.

BACKGROUND: This study was conducted to compare the microbiomes, the levels of lipopolysaccharides (LPS), lipoteichoic acid (LTA), and cytokines (interleukin [IL]-1ß and tumor necrosis factor-alpha [TNF-α]), before and after chemomechanical preparation (CMP) of the root canals (RC) and their associated periodontal pockets (PP) in teeth with combined EPL. MATERIALS: Samples were taken from 10 RC and PP, before and after CMP. The microbiomes (next-generation sequencing, V3-V4 hypervariable region of the 16S rRNA gene), microbiome diversity (bioinformatics analyses), LPS (limulus amebocyte lysate), LTA, IL-1ß, and TNF-α (ELISA) were evaluated. A statistical analysis was performed with significance level set at 5%. RESULTS: The most abundant phyla in both sites were Firmicutes and Proteobacteria. Comparative studies of bacterial genera species revealed that some increased and others decreased after CMP at both sites. A 3% reduction in Gram-negative bacteria (RC) and a 4% increase in Gram-positive bacteria (PP) were detected. LPS levels were 4.4 times higher in PP than in the RC. LTA was detected in all samples investigated. Higher levels of IL-1ß and TNF-α were detected in both sites at baseline. After CMP, LPS, LTA, IL-1ß and TNF-α were reduced in both sites. CONCLUSION: The microbial community in the RC and PP in teeth with combined EPL indicated a similarity between both sites. CMP effectively reduced the microbial load and the LPS levels from teeth with EPL, and consequently diminished the cytokine levels. The reduction in LTA levels in the RC and PP proved challenging.

Epidemiology and severity of traumatic dental injuries in permanent teeth: A 20-year retrospective study.

This study aimed to assess the traumatic dental injuries (TDIs) in permanent dentition among patients who attended at the outpatient clinic of a Brazilian dental school, during the last 20 years, and to investigate factors associated with the severity of these injuries. Clinical records of patients who attended a specialized center for dental trauma care in Brazil presenting at least one TDI in a permanent tooth, between the years 2000 and 2019, were reviewed. The data recorded were sex, age, affected arch, etiology, number, and type of the teeth affected, and classification and severity of the TDIs. The diagnosis and classification of the TDIs were based on the guidelines of the International Association of Dental Traumatology (IADT). The severity of each patient's injuries was defined as mild, moderate, or severe. Descriptive statistics, chi-square and multinomial regression analyses were used to evaluate the results. The significance level was set at 5%. A total of 837 clinical records were included, totaling 2357 teeth. Males were more prevalent than females. The patients' age ranged from 5 to 71 years. The most common traumas were avulsion (n=512) and uncomplicated enamel-dentin fracture (n=488). Univariate analyses showed that there was a statistically significant association between age group (p=0.004), etiology (p=0.000) and number of teeth affected (p=0.000) with severity of dental trauma. In conclusion, TDIs that occurred in Piracicaba and region are epidemiologically similar to those found worldwide, and that more severe injuries are related to age range, etiology and number of teeth affected.

Identification of Culturable and Nonculturable Microorganisms, Lipopolysaccharides, and Lipoteichoic Acids From Root Canals of Teeth With Endodontic Failure.

AIM: To elucidate the presence of apical periodontitis in the root canal of teeth with secondary/persistent infection, including composition of microbiota, levels of endotoxins and lipoteichoic acid (LTA), and clinical implications of these findings. METHOD: Samples were collected from root canals of 50 patients who needed endodontic retreatment and had radiographic evidence of apical periodontitis. Microorganisms were identified by using the culture technique and biochemical tests. Nested-polymerase chain reaction (nested-PCR) was used to identify 17 species of specific bacteria. Lipopolysaccharides (LPS) and LTAs were quantified by using, respectively, limulus amebocyte lysate and enzyme-linked immunosorbent assay tests. RESULTS: Bacteria were detected in all samples by culture and molecular methods. A total of 154 gram-positive strains, of 188 strains isolated, were found in the root canals by culture. Enterococcus faecalis and Gemella morbillorum were the most prevalent species identified by the biochemical tests, whereas molecular analyses (nested-PCR) showed a high frequency of P. gingivalis, E. faecalis, and Fusobacterium nucleatum. LPS and LTA were detected in all samples, with mean values being 3.52 EU/mL and 597.83 pg/mL, respectively. Significant statistical correlations were found between levels of LTA and clinical features. CONCLUSION: Despite the prevalence of gram-positives, the microbiota present in secondary/persistent infections showed a large variety of species. Within this diversity, associations were found between specific bacteria and clinical features. In addition, higher levels of LTA were statistically associated with larger periapical radiolucent areas, but no correlation between this feature and LPS was found.

Occurrence of peri-implant diseases and risk indicators at the patient and implant levels: A multilevel cross-sectional study.

BACKGROUND: High prevalence rates of peri-implant diseases have been reported; however, the lack of standardization of definition criteria has lead to variations in the observed estimates. In addition, scarce data are available concerning patient and implant related factors associated to peri-implantitis. The aim of this study was to determine the prevalence of peri-implant diseases and their risk indicators at the patient and implant levels. METHODS: One hundred forty-seven patients with 490 dental implants were included. Dental implants were clinically and radiographically evaluated to determine their peri-implant conditions. Patient-related conditions and implant and prosthetic-related factors were recorded. Multivariable Poisson regression was fitted and prevalence ratios (PR) were reported. RESULTS: 85.3% of implants (95%CI 80.2 to 90.4) had mucositis and 9.2% (95%CI 4.7 to 13.7) had peri-implantitis. 80.9% (95%CI 73.8 to 86.8), and 19.1% (95%CI 12.6 to 25.5) of patients had mucositis and peri-implantitis. At the patient level, it was observed an increased probability of peri-implantitis in individuals with pocket depths ≥6 mm (PR = 2.47) and with ≥4 implants (PR = 1.96). Smoking increased the probability of peri-implantitis by three times (PR = 3.49). The final multilevel Poisson regression model at the implant level indicated that platform switching reduced the probability of peri-implantitis (PR = 0.18) and implants in function for ≥5 years increased this probability (PR = 2.11). The final model including patient and implant level indicators demonstrated that higher time of function (PR = 2.76) and smoking (PR = 6.59) were associated with peri-implantitis. CONCLUSION: Peri-implant diseases are highly prevalent in the studied sample, and factors associated with the occurrence of peri-implantitis were presence of pockets ≥6 mm, smoking, time of function, and type of platform.

Epidemiology and severity of traumatic dental injuries in permanent teeth: A 20-year retrospective study

Abstract This study aimed to assess the traumatic dental injuries (TDIs) in permanent dentition among patients who attended at the outpatient clinic of a Brazilian dental school, during the last 20 years, and to investigate factors associated with the severity of these injuries. Clinical records of patients who attended a specialized center for dental trauma care in Brazil presenting at least one TDI in a permanent tooth, between the years 2000 and 2019, were reviewed. The data recorded were sex, age, affected arch, etiology, number, and type of the teeth affected, and classification and severity of the TDIs. The diagnosis and classification of the TDIs were based on the guidelines of the International Association of Dental Traumatology (IADT). The severity of each patient's injuries was defined as mild, moderate, or severe. Descriptive statistics, chi-square and multinomial regression analyses were used to evaluate the results. The significance level was set at 5%. A total of 837 clinical records were included, totaling 2357 teeth. Males were more prevalent than females. The patients' age ranged from 5 to 71 years. The most common traumas were avulsion (n=512) and uncomplicated enamel-dentin fracture (n=488). Univariate analyses showed that there was a statistically significant association between age group (p=0.004), etiology (p=0.000) and number of teeth affected (p=0.000) with severity of dental trauma. In conclusion, TDIs that occurred in Piracicaba and region are epidemiologically similar to those found worldwide, and that more severe injuries are related to age range, etiology and number of teeth affected.

Resumo Esse estudo objetivou avaliar as injúrias dentárias traumáticas (IDTs) na dentição permanente entre os pacientes que compareceram ao ambulatório de uma faculdade de odontologia brasileira, durante os últimos 20 anos, e investigar fatores associados à severidade dessas lesões. Os registros clínicos dos pacientes que compareceram a um centro especializado de atendimento em traumatismo dentário no Brasil apresentando pelo menos uma IDT em dente permanente, entre os anos de 2000 e 2019, foram revisados. Os dados registrados foram sexo, idade, arco dental afetado, etiologia, número e tipo dos dentes afetados, e classificação e severidade das IDTs. O diagnóstico e a classificação das IDTs foram baseados nas diretrizes da Associação Internacional de Traumatologia Dentária (AITD). A gravidade das lesões de cada paciente foi definida como leve, moderada ou severa. Estatísticas descritivas, teste qui-quadrado e análises de regressão multinomial foram usadas para avaliar os resultados. O nível de significância foi fixado em 5%. Um total de 837 registros clínicos foi incluído, totalizando 2357 dentes. O sexo masculino foi mais prevalente que o feminino. A idade dos pacientes variou de 5 a 71 anos. Os traumas mais comuns foram avulsão (n=512) e fratura não-complicada do esmalte-dentina (n=488). As análises univariadas mostraram que houve associação estatisticamente significativa entre a faixa etária (p=0,004), etiologia (p=0,000) e número de dentes afetados (p=0,000) com a gravidade do traumatismo dentário. Em conclusão, as IDTs que ocorreram em Piracicaba e região são epidemiologicamente semelhantes aos encontrados em todo o mundo, e que lesões mais graves estão relacionadas à faixa etária, etiologia e número de dentes afetados.