Influence of caries activity and number of saliva donors: mineral and microbiological responses in a microcosm biofilm model.

OBJECTIVE: this study evaluated the mineral and microbiological response of biofilms originating from different types of saliva inoculum with distinct levels of caries activity. METHODOLOGY: the biofilms grown over enamel specimens originated from saliva collected from a single donor or five donors with two distinct levels of caries activity (caries-active and caries-free) or from pooling saliva from ten donors (five caries-active and five caries-free). The percentage surface hardness change (%SHC) and microbiological counts served as outcome variables. RESULTS: the caries activity of donors did not affect the %SHC values. Inoculum from five donors compared to a single donor showed higher %SHC values (p=0.019). Higher lactobacilli counts were observed when saliva from caries-active donors was used as the inoculum (p=0.017). Pooled saliva from both caries activity levels showed higher mutans streptococci counts (p<0.017). CONCLUSION: Overall, pooled saliva increased the mineral response of the derived biofilms, but all the inoculum conditions formed cariogenic biofilms and caries lesions independently of caries activity.

Influence of caries activity and number of saliva donors: mineral and microbiological responses in a microcosm biofilm model

Abstract Objective this study evaluated the mineral and microbiological response of biofilms originating from different types of saliva inoculum with distinct levels of caries activity. Methodology the biofilms grown over enamel specimens originated from saliva collected from a single donor or five donors with two distinct levels of caries activity (caries-active and caries-free) or from pooling saliva from ten donors (five caries-active and five caries-free). The percentage surface hardness change (%SHC) and microbiological counts served as outcome variables. Results the caries activity of donors did not affect the %SHC values. Inoculum from five donors compared to a single donor showed higher %SHC values (p=0.019). Higher lactobacilli counts were observed when saliva from caries-active donors was used as the inoculum (p=0.017). Pooled saliva from both caries activity levels showed higher mutans streptococci counts (p<0.017). Conclusion Overall, pooled saliva increased the mineral response of the derived biofilms, but all the inoculum conditions formed cariogenic biofilms and caries lesions independently of caries activity.

Study protocol for a diagnostic randomized clinical trial to evaluate the effect of the use of two clinical criteria in the assessment of caries lesions around restorations in adults: the Caries Cognition and Identification in Adults (CaCIA) trial.

BACKGROUND: The assessment of restored teeth in dentistry remains a challenge, mainly related to the detection of caries around restorations. There is a diversity of clinical criteria available to assess the caries lesions, resulting in differences in the dentists' diagnosis and treatment decisions. In addition, there is a lack of evidence regarding the best criteria to detect caries lesions around the restorations. Thus, the present protocol aims to evaluate the effect of using 2 visual criteria to assess restored teeth on the outcomes related to oral health in adults. METHODS: The design protocol of the Caries Cognition and Identification in Adults trial correspond to a triple-blind randomized, controlled clinical trial with parallel-groups. Two groups will be compared: patients who will receive the diagnosis and treatment decision according to FDI (World Dental Federation) criteria-FDI group; and patients who will receive diagnosis and treatment decision according to the "Caries Associated with Restorations or Sealants" criteria defined by the International Caries Classification and Management System (ICCMS group). The participants will be followed up after 6, 12, 18, 24, and 60 months, and the restoration failure will be the primary outcome. The analysis will be conducted through Cox regression with shared frailty. The impact of oral health on quality of life and the cost-effectiveness of the methods used will be the secondary outcomes. Two-tailed analyzes will be used, considering a level of significance of 5%. DISCUSSION: This is the first clinical trial to assess the effect of using two visual methods to detect caries lesions around restorations on the outcomes related to oral health in adults. The findings of this study will define what is the best diagnostic strategy for the assessment of caries around restorations in permanent teeth. Trial registration NCT03108586 (registered 11 April 2017).

Desenvolvimento de lesões de cárie em dentina em um modelo de biofilme simplificado in vitro: um estudo piloto / Development of dentin caries lesions in an in vitro simplified biofilm model: a pilot study

Introdução: Modelos laboratoriais de biofilmes vêm sendo desenvolvidos com a finalidade de simular o ambiente bucal e o processo de formação da cárie dental. Objetivo: Estabelecer e padronizar um modelo de biofilme in vitro para o desenvolvimento de lesões de cárie em dentina. Material e método: Doze discos padronizados de dentina bovina foram divididos em três tempos experimentais: 4, 7 e 10 dias. As amostras de cada tempo experimental foram inoculadas com Streptococcus mutans UA 159 em meio de cultura BHI com 1% de sacarose e cultivadas em anaerobiose. As variáveis de resposta foram a perda de dureza integrada (ΔS) dos discos de dentina e dureza do substrato em diferentes profundidades. Os dados de ΔS foram analisados através de ANOVA seguido do teste Tukey, ambos com significância de 5%, e os dados de dureza de profundidade de lesão analisados descritivamente. Resultado: Houve maior perda mineral aos 10 dias de crescimento microbiológico quando comparados aos 4 dias (p = 0,034), no entanto não houve diferença entre 7 e 10 dias (p = 0,853). O grupo de 4 dias mostrou perda de dureza em regiões mais superficiais (10-40µm); e o grupo de 10 dias mostrou desmineralização em áreas mais profundas, até 150 µm. Conclusão: O modelo proposto mostrou-se capaz de desenvolver lesões de cárie artificiais em dentina. Em 7 dias, as lesões subsuperficiais de dentina foram adequadas para estudos de des-remineralização.

Introduction: Oral laboratory biofilm models have been developed to reproduce the oral environment and the process of caries lesion formation in vitro. Objective: To establish and standardize an in vitro biofilm model for the development of caries lesions in dentin. Material and method: Twelve standardized bovine dentin discs were assigned into three experimental times: 4, 7, and 10 days. Samples of each experimental period were inoculated with Streptococcus mutans UA 159 in a BHI culture medium with 1% sucrose, and cultured under anaerobic conditions. The integrated hardness loss (ΔS) of dentin discs and the hardness of the substrate at different depths were considered as response variables. The ΔS data were analysed by ANOVA followed by Tukey's test, both with significance level of 5%, and the data of hardness at different depths were analysed descriptively. Result: There was a higher hardness loss after 10 days of microbial growth when compared to 4 days (p = 0.034), however, there was no difference between 7 and 10 days (p = 0.853). The 4-day group showed loss of hardness of the surface layers (10-40μm) and the 10-day group showed demineralization in the deeper area around 150µm. Conclusion: The proposed model was able to develop artificial caries lesions in dentin. In 7 days, the dentin sub superficial lesions were suitable to des-remineralisation studies.

Impact of a Tutored Theoretical-Practical Training to Develop Undergraduate Students' Skills for the Detection of Caries Lesions: Study Protocol for a Multicenter Controlled Randomized Study.

BACKGROUND: Tutored laboratorial activities could be a manner of improving the competency development of students. However, its impact over conventional theoretical classes has not yet been tested. Additionally, different university contexts could influence this issue and should be explored. OBJECTIVE: To assess the impact of a tutored theoretical-practical training for teaching undergraduate students to detect caries lesions as compared with theoretical teaching activities. The impact of these teaching/learning activities will be assessed in terms of efficacy, cost/benefit, retention of knowledge/acquired competences, and student acceptability. METHODS: Sixteen centers (7 centers from Brazil and 9 centers from other countries throughout the world) are involved in the inclusion of subjects for this protocol. A randomized controlled study with parallel groups will be conducted. One group (control) will be exposed to a 60- to 90-minute conventional theoretical class and the other group (test) will be exposed to the same theoretical class and also a 90-minute laboratory class, including exercises and discussions based on the evaluation of a pool of images and extracted teeth. The mentioned outcomes will be evaluated immediately after the teaching activities and also in medium- and long-term analyses. To compare the long-term outcomes, students who enrolled in the university before the participating students will be interviewed for data collection and these data will be used as a control and compared with the trained group. This stage will be a nonrandomized phase of this study, nested in the main study. Appropriate statistical analysis will be performed according to the aims of this study. Variables related to the centers will also be analyzed and used to model adjustment as possible sources of variability among results. RESULTS: This ongoing study is funded by a Brazilian national funding agency (CNPq- 400736/2014-4). We expect that the tutored theoretical-practical training will improve the undergraduate students' performance in the detection of caries lesions and subsequent treatment decisions, mainly in terms of long-term retention of knowledge. Our hypothesis is that tutored theoretical-practical training is a more cost-effective option for teaching undergraduate students to detect caries lesions. CONCLUSIONS: If our hypothesis is confirmed, the use of laboratory training in conjunction with theoretical classes could be used as an educational strategy in Cariology to improve the development of undergraduate students' skills in the detection of caries lesions and clinical decision-making.

Incomplete caries removal in deep lesions: a 10-year prospective study.

PURPOSE: To follow-up teeth with deep caries lesions submitted to incomplete caries removal over a 10-year period. METHODS: 27 subjects (32 permanent posterior teeth) with deep caries lesions composed the sample. In this single-arm long-term prospective study, the inclusion criteria were risk of pulp exposure during caries excavation, positive response to the cold test, absence of spontaneous pain or sensitivity during percussion, and radiographic absence of a periapical lesion. Subjects were submitted to the following procedures: complete caries removal from the surrounding cavity walls, incomplete caries removal from the pulpal wall, capping with a calcium hydroxide cement, and sealing with a modified zinc oxide-eugenol cement. After 6-7 months, the temporary sealing was removed for methodological purposes (no further excavation was performed), and teeth were capped with a calcium hydroxide cement and filled with resin composite. Clinical and radiographic assessments were conducted after 6-7 months, 1.5, 3, 5 and 10 years. Success was defined as clinical and radiographic signs and symptoms of pulp sensitivity while failure was defined as endodontic treatment need. RESULTS: Over 10 years, one tooth was excluded from the sample (pulp exposure during treatment), five were lost to recall, 10 had therapy failure (five fractures and four necroses leading to endodontic treatment need, and one extraction) and 16 had therapy success (pulp sensitivity). Overall survival rates were 97%, 90%, 82% and 63% at 1.5-, 3-, 5- and 10-year follow-ups, respectively. Teeth with two or more restored surfaces failed significantly more than teeth with one restored surface (P= 0.01).