Is there bacterial infection in the intact crowns of teeth with pulp necrosis of sickle cell anaemia patients? A case series study nested in a cohort.

AIM: To evaluate the presence of bacteria in permanent teeth with intact crowns (without caries, periodontal disease or dental trauma) in patients with sickle cell anaemia (HbSS genotype) by analysing their clinical, imaging and microbiological parameters. METHODOLOGY: This is a case series study nested in a cohort. In the first follow-up of this cohort study (Journal of Endodontics, 2013, 39, 177), 10 HbSS patients with at least one tooth with an intact crown and clinically diagnosed with pulp necrosis by pulse oximetry adapted for dentistry and a cold pulp sensitivity test (n = 27 teeth) were selected. Changes in the pulp chamber, root and periodontal ligament were identified in the tomographic analysis. Bacterial culture, staining for live and dead bacteria, and real-time polymerase chain reaction with 16S rRNA primers were used to identify the presence of bacteria. Culture sample collection was performed immediately after access to the pulp chamber. The microbiome was analysed with a MiSeq sequencer (Illumina, San Diego, CA). RESULTS: The diagnosis of pulp necrosis was confirmed clinically in 82% (22/27) of the teeth. The amount of bacterial load identified was less than 100 copies µL-1 in 23% (5/22) of the teeth with intact crowns and pulp necrosis. Thirteen bacterial species were identified that are commonly found in urinary tract infections, septicaemia and infective endocarditis. Only one of these species, Granulicatella adjacens, has also be found in primary endodontic infections. CONCLUSION: Prospective clinical, imaging and microbiological analyses suggest that pulp necrosis of teeth with intact crowns in HbSS patients is not associated with the presence of bacteria.

Are sickle cell anaemia and sickle cell trait predictive factors for periodontal disease? A cohort study.

BACKGROUND AND OBJECTIVE: Periodontal diseases are associated with bacterial challenge and the host immune response, and are also modulated by genetic factors. There is evidence that sickle cell anaemia (SCA) does not represent a risk factor for periodontal diseases. However, it is still unclear whether the heterozygous condition [sickle cell trait (SCT)] is associated with periodontal diseases. SCT is a genetic condition that can cause vaso-occlusive events, which may be associated with a propensity to bacterial infections. The aim of this study was to investigate the association of SCA and SCT with periodontal diseases by evaluating clinical and radiographic characteristics. MATERIAL AND METHODS: The sample (n = 369) was selected and divided into two groups: exposed groups [HbSS (SCA genotype) and HbAS (SCT genotype) = 246] and a nonexposed group (HbAA = 123). HbAA consisted of individuals without SCA and SCT. The clinical parameters evaluated were plaque index, gingival index, calculus index, clinical probing depth, clinical attachment level, gingival recession, tooth mobility and furcation involvement. The percentage of alveolar bone loss was measured using a Schei ruler. Binomial and Poisson regressions were used to estimate correlations of interest (α = 0.05). RESULTS: None of the periodontal parameters was associated with SCA. SCT was associated with gingivitis (p = 0.041) and periodontitis (p = 0.002). Individuals with SCT had a lower plaque index (p = 0.044) but a higher calculus index (p = 0.003) and greater alveolar bone loss (p = 0.010) compared with subjects in the HbAA group. CONCLUSIONS: SCT can act as a predictor for establishment of periodontal diseases. There was no correlation between SCA and periodontal diseases.

Polymerization stress, flow and dentine bond strength of two resin-based root canal sealers.

AIM: To compare two resin-based root canal sealers (AH Plus and dual cure Epiphany) in terms of flow, polymerization stress and bond strength to dentine. METHODOLOGY: Flow was evaluated by measuring the diameter of uncured discs of sealer (0.5 mL) after 7 min compression (20N) between two glass plates (n = 5). Polymerization stress was monitored for 60 min in 1-mm thick discs bonded to two glass rods (Ø = 5 mm) attached to a universal testing machine (n = 3). Bond strength was analyzed through micropush-out test (n = 10) and failure mode was examined with scanning electron microscope (100x and 2500x). Data were statistically analyzed using the Student's t-test (alpha = 0.05). RESULTS: Polymerization stress was 0.32 +/- 0.07 MPa for Epiphany self-cure, 0.65 +/- 0.08 MPa for Epiphany light-cure and zero for AH Plus (P < 0.05). Flow data and bond strength values were 30.9 +/- 1.1, 28.6 +/- 0.7 mm and 6.3 +/- 5.3, 17.8 +/- 7.5 MPa for Epiphany and AH Plus, respectively (P < 0.001). Failure mode was predominantly cohesive in the sealer for both materials. CONCLUSIONS: Epiphany had higher flow and polymerization stress and lower bond strength values to dentine than AH Plus. In view of these findings it can be implied that AH Plus would provide a better seal.

Resultados da aplicação tópica do extrato de própolis na redução da progressão da doença periodontal / Results of topical application of propolis extracts in reducing progression of periodontal disease

RESUMO Agentes químicos têm sido usados para auxiliar na inibição da formação do biofilme e impedir desenvolvimento da doença periodontal (DP). O objetivo deste estudo foi avaliar radiograficamente a ação do extrato de própolis na progressão da DP induzida em ratos. Foram utilizados 48 ratos Wistar, divididos em 4 grupos (n=12): Controle, Pincel, Própolis e Clorexidina. Os grupos foram subdivididos para análise aos 7 e 21 dias. A progressão da DP foi avaliada radiograficamente pela distância entre a junção cemento-esmalte e a crista óssea alveolar na face mesial do 1º molar inferior. A perda óssea foi significativamente menor nos animais do grupo própolis em ambos os períodos (p ≤ 0,01). Concluiu-se por análise radiográfica que a aplicação tópica do extrato de própolis interfere reduzindo a progressão da doença periodontal induzida por ligadura em ratos, demonstrando a importância desse composto como substância auxiliar no tratamento periodontal.

ABSTRACT Chemical agents have been used to assist on inhibiting biofilm formation and on preventing the development of periodontal disease (PD). The aim of this study was to radiographically evaluate the action of propolis extract on the progression of PD induced in rats. 48 Wistar rats were divided into 4 groups (n = 12): Control, Brush, Propolis and Chlorhexidine. The groups were subdivided for analysis at 7 and 21 days. The progression of the periodontal disease was radiographically assessed by the distance between the cement-enamel junction and the alveolar bone crest mesial of the 1st molar. Bone loss was significantly lower in the Propolis group in both periods (p ≤ 0.01). By radiographic analysis, it is concluded that the topical application of propolis extract interferes by reducing the progression of ligature-induced periodontal disease in rats, demonstrating the importance of this compound as an auxiliary substance in periodontal treatment.

Effectiveness of 2% chlorhexidine gel and calcium hydroxide against Enterococcus faecalis in bovine root dentine in vitro.

AIM: To evaluate the effectiveness of 2% chlorhexidine gluconate gel and calcium hydroxide (Ca(OH)2) as intracanal medicaments against Enterococcus faecalis. METHODOLOGY: One hundred and eighty dentine tubes prepared from intact freshly extracted bovine maxillary central incisors were infected in vitro for 7 days with E. faecalis. The specimens were divided into four groups, according to the intracanal medicament used, as follows: Group 1: 2% chlorhexidine gluconate gel; Group 2: calcium hydroxide in a viscous vehicle (polyethyleneglycol 400); Group 3: 2% chlorhexidine gluconate gel + calcium hydroxide and Group 4: Brain Heart Infusion (BHI) broth (control group). The medicaments were placed into the canal lumen and left there for experimental times of 1, 2, 7, 15 and 30 days. After each period, irrigation with sterile saline to remove the medicament was performed and the canals were dried with sterile paper points. Dentine chips were removed from the canals with sequential sterile round burs at low speed. The samples obtained with each bur were immediately collected in separate test tubes containing BHI broth. The tubes were incubated at 37 degrees C and daily observed for microbial growth, visualized by the medium turbidity. RESULTS: Chlorhexidine gel alone completely inhibited the growth of E. faecalis after 1, 2, 7 and 15 days. Calcium hydroxide allowed microbial growth at all experimental times. The combination of chlorhexidine and Ca(OH)2 was effective after 1 and 2 days demonstrating 100% antibacterial action; however, its antibacterial activity reduced between 7 and 15 days. CONCLUSION: Under the conditions of this study, it can be concluded that 2% chlorhexidine gel alone was more effective against E. faecalis than calcium hydroxide (P < 0.05). However, its antibacterial activity depended on how long it remained inside the root canal.