MTT versus other cell viability assays to evaluate the biocompatibility of root canal filling materials: a systematic review.

OBJECTIVES: This systematic review aimed to compare the cytotoxicity of root canal filling materials (RCFMs) assessed using tetrazolium salt-based tests (TSBT), including the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, with those obtained using other cell viability assays. METHODS: A search was performed on PubMed, Scopus, Web of Science and OpenGrey up to March 2019, followed by a manual search. According to the Participants, Exposure, Comparator and Outcomes (PECO) criteria, in vitro studies that evaluated the cytotoxic effect of RCFMss on animal and/or human cells through TSBT and at least one other viability assay were compared. The methodological quality of selected papers was assessed using ToxRTool® and SciRAP® . Data were analysed using Wilcoxon's signed-rank test for paired samples and linear weighting kappa. RESULTS: A total of 230 non-duplicated records were identified. After applying the eligibility criteria, 55 studies were selected for methodological evaluation, seven were selected by manual searching, 22 were excluded for methodological reasons, and 40 were included. A total of 410 comparisons were performed between TSBT and distinct cell viability tests (DCVT). MTT had moderate concordance with DCVT using human cells (n = 138 samples) (P = 0.507; k = 0.4225) and animal cells (n = 122 samples) (P = 0.124; k = 0.5775). XTT had good concordance using human (n = 110 samples) (P = 0.507; k = 0.6336) and animal cells (n = 12 samples) (P = 0.564; k = 0.6604). MTT, XTT, WST and MTS assays showed moderate concordance with DCVT (n = 410 samples) (P = 0.375; k = 0.5138) and complete agreement in 226 samples. DISCUSSION: The included studies had methodological heterogeneity that was minimized by the systematic review methodology. CONCLUSIONS: MTT and XTT do not cause over- or underestimation of cell viability during cytotoxicity screening of root canal filling materials, implying that these assays can be considered reliable for this purpose. Nonetheless, the development of protocols for the cytotoxic screening of these materials on 3D tissue-like cultures aiming to improve their predictability in the clinical scenario is suggested.

Analysis of root canal treated primary incisor after trauma: two year outcomes.

BACKGROUND: The low number of clinical studies of traumatized teeth submitted to root canal treatment is completely out of proportion to the seriousness that dental trauma imposes on children in early years. AIM: This study evaluates the outcomes of root canal treatment (RCT) in traumatized primary incisors and identifies the predisposing factors associated with therapy success. METHODS: This is a retrospective study conducted with all dental records of 704 patients who had one or more teeth with traumatic injuries. Patients with irreversible pulp changes in primary teeth leading to RCT with a 24 month follow-up met the inclusion criteria. RESULTS: Twenty-five maxillary incisors of 17 children were evaluated. The children's age at the time of therapy ranged from 24 to 72 months (mean 47.3). Pulp necrosis was the most common disorder (84.0%) and pre-operative periapical lesions were observed in 52.0%. Coronal discoloration was found in 48.0%. The roots were filled with ZOE paste (68.0%) or Guedes-Pinto paste (32.0%). Overall RCT success rate was 68.0%. The absence of pre-operative periapical lesions (p = 0.02) and pathological root resorption (p = 0.02) presented positive association with therapy success. Success was not associated to filling paste (p = 0.49), filling extent (p = 0.44), of discoloration (p = 0.39) nor the patients' age (p = 0.59). CONCLUSIONS: RCT was considered successful in 68.0% of the cases at the 24 month follow-up. Failure of RCT in traumatized primary incisors was associated with pre-operatory periapical lesions and pathological root resorption. The filling paste, the filling extent and the patient's age were unrelated with therapy success.

Short communication: polymicrobial community in teeth associated with severe early-childhood caries.

AIM: This was to characterise the microbial diversity in the complex dental plaque of children with severe early-childhood caries (S-ECC), using the denaturing gel gradient electrophoresis (DGGE) technique. METHODS: The DGGE technique was used as a diagnostic tool to analyse samples from the oral cavity of a patient with S-ECC. Dental plaque samples from a 3-year-old child with S-ECC were taken from the primary central maxillary incisor (biofilm on vestibular surface), primary maxillary molar (biofilm on vestibular surface), primary central maxillary incisor (dentine), primary maxillary molar (dentine) and saliva and then analysed by PCR-DGGE. RESULTS: Three bands occurred in all samples, moreover, 86% of similarity was observed in the pattern of bands between incisor and molar teeth biofilm samples, including four similar bands. CONCLUSION: DGGE is a valuable tool for differentiating the microbial composition of the oral plaque in S-ECC children.

ZOE paste pulpectomies outcome in primary teeth: a systematic review.

OBJECTIVE: To perform a systematic review in which the clinical research question for primary teeth with irreversible pulpal pathosis was "how pulpectomies with zinc oxide eugenol (ZOE) paste performed compared to other materials in their clinical and radiographic outcomes after twelve months or more follow-up period. STUDY DESIGN: A literature survey of the electronic database (1950-2010) used the Medical Subject Headings and free text terms. Forty three references were retrieved and inclusion criteria were applied; 15 articles remained for full-text evaluation. From these, two were selected for data extraction regarding quality characteristics and results. RESULTS: Selected studies showed moderate or high risk of bias. The overall success of pulpectomy was 80.0% (Calcicur), 60.0% (Sealapex) and varied from 85.0% to 100.0% (ZOE) and 89.0% to 100.0% (Vitapex). Solely Calcicur presented success rate significantly lower when compared to ZOE and Vitapex. These pastes lead to overfilled canals and particles of extruded ZOE were still evident even after the evaluation period. Resorption of Vitapex, Calcicur and Sealapex within the root canal was also reported. CONCLUSIONS: In primary teeth with irreversible pulpal changes ZOE pulpectomies yielded similar outcome than Vitapex and Sealapex, although there was no agreement with regard to filling materials' resorption.

Zinc oxide-eugenol paste retained in gingival mucosa after primary teeth pulpectomy.

AIM: Long-term follow-up evaluations of pulpectomy in primary teeth have revealed retention of ZOE filling particles in the periapical area even after root resorption. CASE REPORT: This paper reports a case of a child submitted to pulpectomy with ZOE paste in primary teeth. After 28 months, the filling particles remained, having migrated to the alveolar bone from the gingival vestibular mucosa during permanent dentition eruption. Aesthetics required periodontal surgical removal of the paste particles. Primary teeth submitted to pulpectomy should be evaluated carefully both clinically and radiographically to verify radicular and ZOE filling paste resorption. The consequences of retained particles during permanent dentition eruption are unknown.

Microhardness of dentine underlying ART restorations in primary molars: an in vivo pilot study.

OBJECTIVE: To evaluate the microhardness of dentine underlying glass ionomer restorations made with Atraumatic Restorative Treatment. DESIGN: An experimental single-centre study. SETTING: University Department, Brazil, 2001. MATERIALS AND METHODS: Sixteen children were selected showing primary molars containing carious cavities (n = 29), which were restored using Fugi IX. Subsequently, some teeth were extracted respecting Nolla stage 7 or 8 of the permanent successor, and categorised according to the post-restoration time in the mouth: G1 (baseline, immediate extraction), G2 (30 days), G3 (90 days) and G4 (180 days). Four teeth were excluded because they were not in time of normal exfoliation. The 25 extracted teeth were resin embedded, sectioned mesiodistally and prepared metallographically. Knoop microhardness analysis (Micromet 2003; 10g for 1.5 sec.) produced identations in three areas of dentine: Zone 1 (just below the restoration), Zone 3 (as close as possible to the pulp) and Zone 2 (intermediate region between 1 and 3). Non-parametric statistical tests were done--at a significance level of 5%. RESULTS: Four teeth were excluded. No significant difference was noted among the zones, inside the groups. Zones 1 and 2 showed a considerable increase of microhardness according to the time, except for Group 3 (p > 0.05). CONCLUSION: Although microhardness had increased, it was not sufficiently equal to the microhardness of the healthy dentine, regardless of the depth evaluated.

Case report: ultrasonic cavity preparation -- an alternative approach for caries removal in paediatric dentistry.

BACKGROUND: Since the invention and application of rotating instruments, the operative treatment of carious lesions has often resulted in considerable removal of tooth structure. Moreover, conventional caries removal and cavity preparation by a combination of the use of a turbine and a handpiece with a bur presents disadvantages to very young patients, whose perception of drilling is unpleasant. This report concerns an alternative approach for caries removal in a child using ultrasound and discusses the advantages and disadvantages of this technique. CASE REPORT: A 2-year-old male child was brought by his mother to a private paediatric dental clinic in Rio de Janeiro, Brazil. The mother's main complaint was the presence of dental caries in her son's anterior teeth. Intraoral clinical examination revealed that the patient had two carious lesions in the maxillary central incisors on mesial surfaces. Cavity preparation was performed using ultrasound and restoration with a light-curing resin. FOLLOW-UP: One year and a half after the restorative procedure the patient presented with the restored teeth in perfect condition.

Microscopic investigation of artificially demineralized surface enamel exposed to controlled intra-oral periods.

BACKGROUND: Arrest and regression of enamel caries is generally followed by clinical surface changes in enamel. The aim of this study was to evaluate microscopic surface changes in demineralized enamel submitted to toothbrushing with a fluoridated dentifrice or to a fluoridated gel in situ. METHODS: Enamel blocks demineralized by an acidic gel, were built in plates of five volunteers during three periods of 14 days each: exposure to the oral cavity (C+); brushing with a fluoridated dentifrice three times a days (B); application of a 2 per cent sodium fluoride gel and exposure to the oral cavity (F). Eight blocks were kept in 100 per cent humidity under refrigeration as negative controls (C-). RESULTS: Stereomicroscopic examination revealed that 15, 47.4 and 30 per cent of samples from C+, B and F presented enamel cavitation after the experimental period. The demineralized enamel area in these groups decreased considerably compared to C-, both in cavitated and non-cavitated samples, although it was statistically significant only in cavitated samples from B (p=0.003; t test). Scanning electron microscopy revealed that C+ and F retained irregularities caused by the acid challenge, while B presented a more leveled profile of the enamel surface. CONCLUSIONS: Exposure of demineralized enamel to intra-oral periods reduced the demineralized enamel area. Tooth brushing enhanced this reduction, because of surface abrasion.

Evaluation of the palate dimensions of patients with perennial allergic rhinitis.

OBJECTIVE: The purpose of this study was to compare the transverse and vertical palate dimensions of two groups of children, one diagnosed as having perennial allergic rhinitis (PAR) and the other without any respiratory pathology. DESIGN: Case-control study. SETTING: Institute of Paediatrics and Child Care of the Federal University of Rio de Janeiro. SAMPLE AND METHODS: The sample consisted of 101 children with the diagnoses of PAR (mean age 6.5) and 91 without any respiratory pathology (mean age 7.3). From 192 patients, 65% was in mixed dentition phase and 35% in primary dentition. Each subject underwent an intra-oral clinical examination using three-dimensional Korkhaus compass to measure the intermolar distance, intercanine distance and palate depth. RESULTS: The allergic group showed greater averages of palate depth (P = 0.00), both in the primary dentition phase (11.53 mm x 10 mm) and in the mixed dentition (11.96 mm x 10.21 mm). There was no statistically significant difference for intermolar and intercanine distances, either in primary or mixed dentition (P > 0.05). CONCLUSION: The transverse dimension of the palate did not vary significantly between the groups, which seems to confirm that the main influence of alteration of the breathing pattern from nasal to mouth occurs on the vertical plane.

Fluoride uptake in situ after the use of dental floss with fluoride.

The possibility of having a commercial product such as waxed floss with an additional agent for controlling and preventing caries is promising. The aim of this research was to determine the uptake of fluoride on tooth enamel in situ after the utilization of a dental floss with fluoride incorporated into the wax. One hundred blocks of bovine enamel were artificially demineralized and randomly separated into a Control Group (C) and a Test Group (T). The dental blocks in group T were mounted two-by-two simulating proximal contacts and were fixed into intra-oral lower arch devices. Eight volunteers with a similar salivary flow and buffer capacity wore devices with the enamel blocks for eight days. During this period of time the subjects applied a 25 cm long portion of a mint waxed floss with fluoride (0.15 mgF/m, Oral-B) between the blocks, 3 times a day for 2 minutes after each meal. At the same time, brushing was carried out with a fluoride-free toothpaste. The alkali-soluble fluoride (CaF2) formed on the enamel was extracted using the Caslavska et al. method and measured with the Orion 96-09 electrode-specific and the EA 720 ion analyzer. The results showed that the group that had the most CaF2 on the enamel (median, minimum and maximum in microF/cm2) was Group T (3.00, 2.11 and 4.00), which differed significantly (p < 0.01) from group C (0.26, 0.10 and 0.69). It was concluded that fluoride uptake on enamel was 11.54 times higher after use of dental floss with fluoride in this study.

Interruption of breast feeding caused by the presence of neonatal teeth.

The authors report the case of a 6-month old girl treated at the Pediatric Dentistry Clinic at the School of Dentistry of the Federal University of Rio de Janeiro. The patient's breast feeding was interrupted prematurely due to the presence of neonatal teeth. The authors have included a brief review of previous reports of this pathology.

Freqüência de trichomoníase vaginal em gestantes atendidas na Maternidade-Escola Ana Nery, Manaus - Amazonas

Summary The occurrency of vaginal trichomoniasis was investigated in pregnant women in the city of Manaus. Amazonas during de second semester of 1977. 313 women were randomly chosen to participate in the study. From the clientela of the prenatal, clinic of the main State Maternity Home. Freshly collected specimens of vaginal cavity were examined directly. 63.9% of the women were shown to be infected with trichomonas. It was also shown that the majority of pregnant mothers sought medical advice in the seventh month of pregnancy, infections were most frequent in mothers in the second pregnancy. The results are discussed and compared with other studies, both national and international.

Resumo É estudada a incidência da trichomoníase vaginal em gestantes na cidade de Manaus. Das pacientes que deram entrada no serviço de pré-natal da Maternidade-Escola "Ana Nery" durante o segundo semestre de 1977, 313 foram escolhidas ao acaso para participarem do estudo. Realizou-se o exame a fresco direto do material coletado da cavidade vaginal, por um swab esterilizado. Em 63.9% das pacientes o protozoário estava presente no material examinado. Verificou-se que o maior número de gestantes procurou os serviços médicos no sétimo mês de gestação e o maior número de infectadas estava na segunda gravidez. Os resultados obtidos são comparados com aqueles citados por outros autores nacionais e estrangeiros.

Freqüência de trichomoníase vaginal em gestantes atendidas na Maternidade-Escola Ana Nery, Manaus - Amazonas

Summary The occurrency of vaginal trichomoniasis was investigated in pregnant women in the city of Manaus. Amazonas during de second semester of 1977. 313 women were randomly chosen to participate in the study. From the clientela of the prenatal, clinic of the main State Maternity Home. Freshly collected specimens of vaginal cavity were examined directly. 63.9% of the women were shown to be infected with trichomonas. It was also shown that the majority of pregnant mothers sought medical advice in the seventh month of pregnancy, infections were most frequent in mothers in the second pregnancy. The results are discussed and compared with other studies, both national and international.

Resumo É estudada a incidência da trichomoníase vaginal em gestantes na cidade de Manaus. Das pacientes que deram entrada no serviço de pré-natal da Maternidade-Escola "Ana Nery" durante o segundo semestre de 1977, 313 foram escolhidas ao acaso para participarem do estudo. Realizou-se o exame a fresco direto do material coletado da cavidade vaginal, por um swab esterilizado. Em 63.9% das pacientes o protozoário estava presente no material examinado. Verificou-se que o maior número de gestantes procurou os serviços médicos no sétimo mês de gestação e o maior número de infectadas estava na segunda gravidez. Os resultados obtidos são comparados com aqueles citados por outros autores nacionais e estrangeiros.