Mineral density in carious dentine after treatment with calcium silicates and polyacrylic acid-based cements.

AIM: To test the hypothesis that polyacrylic acid-based and calcium silicate materials are able to increase mineral density of artificially demineralized dentine produced by a microcosm model for caries formation. METHODOLOGY: Forty-five dentine cavities were prepared in nine sound human third molars (five in each tooth). Specimens received a bacterial inoculum and were incubated in BHI plus 5% of sucrose for 96 h to allow biofilm formation. After that, the specimens were scanned in a high energy micro-CT (baseline stack) and then, each cavity was filled with different cements: zinc polycarboxylate (Poly Zinc™, Prevest DenPro, Jammu, India), conventional glass-ionomer (Ketac Molar, 3M ESPE, Seefeld, Germany) and two calcium silicate-based materials (MTA, Angelus, Londrina, Brazil and Biodentine™, Septodont, Saint Maur des Fosses, France) whilst the central cavity was filled with utility wax (negative control). Specimens were kept for 45 days under simulated intrapulpal pressure using simulated body fluid and after, they were again scanned (treated stacks). Reconstruction of the acquired projections was accomplished using standardized parameters, and the percentage mineral density change was calculated around each cavity. Data were tested for normality using the Shapiro-Wilk test, followed by nonparametric methods. RESULTS: A microcosm artificial caries model was able to cause dentine demineralization (±90% related to sound dentine). Significant increases in dentine mineral density were achieved using MTA or Poly Zinc™ (43.56% and 41.64% remineralization), followed by Biodentine™ (36.40%) and Ketac Molar (32.54%), P < 0.05. CONCLUSION: All cements increased mineral density in demineralized dentine, but zinc polycarboxylate cement and MTA had greater bioactive potential. Micro-CT proved to be an effective method to evaluate changes in mineral density within dentine in contact with bioactive materials.

Effect of organic solvents and ultrasound on the removal of orthodontic brackets.

OBJECTIVE: To evaluate the effect of organic gel solvents (70% acetone and 90% ethanol) and ultrasound in the removal of metallic brackets. MATERIALS AND METHODS: Metallic brackets were bonded with light-cured orthodontic composite (Transbond XT) in 120 human bicuspids and divided into 6 groups for the enamel etch-and-rinse adhesive system (XT) and 6 groups to self-etching system (SEPT) according to pretreatment to removal test: control, 70% acetone, 90% ethanol, ultrasound, 70% acetone+ultrasound, and 90% ethanol+ultrasound. The brackets were subjected to removal by shear testing and Adhesive Remnant Index (ARI) evaluation. Some specimens were prepared and its adhesive interface and etching ability observed by scanning electron microscopy (SEM). RESULTS: Only the factor 'ultrasound' and its interaction with 'adhesive' were detected as a source of variance, with the SEPT/ultrasound showing the lowest shear strength than the other groups. Regardless the factor 'ultrasound', XT showed a higher ARI than SEPT; however, when the solvents were used, no differences were detected between XT and SEPT. CONCLUSION: The organic solvents were not effective in reducing shear bond strength. The etch-and-rinse adhesive system showed a higher and more favorable ARI score than the self-etching primer. The behavior of the organic solvents on ARI showed to be better when associated with the self-etching primer. The ultrasound was effective in reducing the shear bond strength of the self-etching adhesive system but not in affecting the ARI of the adhesive systems.

Brazilian dentist's knowledge of minimum intervention dentistry for caries management: application of a developed knowledge scale (MIDDeC-KS) and evaluation of its psychometric properties.

AIM: To assess the knowledge of Brazilian dentists about Minimum Intervention (MI) using a Minimum Intervention Dentistry to Dental Caries-Knowledge Scale (MIDDeC-KS) and evaluate its psychometric properties. MATERIALS AND METHODS: An online scale was developed to evaluate dentists' knowledge about MI. The higher the score, the greater the knowledge and vice versa. A preliminary study was carried out with 143 dentists to validate the MIDDeC-KS. For psychometric properties analysis, convergent and discriminant validity, test-retest reliability, and internal consistency of the instrument were assessed. After validation, MIDDeC-KS was applied to a representative sample of Brazilian dentists. T test for independent samples, Chi-square, and/or ANOVA one-way tests were applied. RESULTS: The MIDDeC-KS convergent (Spearman's = 0.48) and discriminant (P = 0.001) validity and reliability (ICC = 0.85, α = 0.72 and ω = 0.74) were proved. The participants (n = 637) obtained an overall mean score of 7.4 ± 2.5. The sample was mainly composed of females (P < 0.01), who graduated over 10 years prior (P = 0.02), from public colleges (P < 0.01), and most were pediatric dentists (38.2%). The highest and lowest scores were reached by pediatric dentists (9.2 ± 1.6) and bucomaxillofacial professionals (3.1 ± 2.1), respectively. Brazilian dentists demonstrated more knowledge about diet, biofilm, and topical fluoride control (84.3%), while the Hall technique (31.9%), resin infiltrant (47.6%), and chemical mechanical caries removal (48.4%) were the least known MI techniques. CONCLUSION: Brazilian dentists demonstrated more knowledge about preventive measures and less about more recent protocols, such as the Hall technique, resin infiltrant, and chemical mechanical caries tissue removal. Sufficient psychometric evidence of the MIDDeC-KS was found. CLINICAL RELEVANCE: Identify dentist's knowledge about MI.

Assessment of the reliability of YouTube™ videos about zirconia crowns in pediatric dentistry.

PURPOSE: To evaluate the reliability of YouTube™ videos on zirconia crowns in pediatric dentistry. METHODS: On January 4, 2022, a search was performed using the term "pediatric zirconia crown". The first 100 videos on the subject were included. Non-English videos, duplicates, and off-topic videos were excluded. For each video, an examiner recorded the number of views, likes, comments, channel followers, upload date, duration, and category rating. Two examiners assessed the reliability of the information presented in the videos using DISCERN, a brief questionnaire and scale score used to assess in a valid and reliable way the quality of information on treatment choices for health problems. Descriptive and inferential analyses were performed (p < 0.05). RESULTS: Of the initial 100 videos, 72 were excluded because of language, duplication, and subject matter. The 28 remaining videos had an average of 3.5 comments, 8,896.18 channel followers, 5,614.00 views, 19.14 likes, and a duration of 840.32 s. The average view rate was 7.54 per day ± 10,206.81. There was a statistically significant difference between the number of views and comments (p < 0.001), likes and comments (p < 0.001), and likes and views (p = 0.006). According to the DISCERN, none of the videos received the maximum grade to be considered very good. Two were considered good, nine fair, fourteen poor, and three very poor. CONCLUSION: Given that the majority of YouTube™ videos currently available on zirconia crowns in pediatric dentistry were deemed unreliable according to the DISCERN questionnaire, caution should be exercised when using the information presented.

Modified thermoplastic plate: a new proposal for correction of exaggerated overbite in mixed dentition.

Exaggerated overbite can be corrected by several treatment modalities. As the primary objective is to correct the problem by addressing its root cause, treatment options are closely related to etiology. Therefore, the main treatment strategies are: the extrusion of posterior teeth, intrusion of teeth (maxillary/mandibular) or the combination of these. The purpose of this paper is to describe the fabrication of a modified thermoplastic plate (MTP) for correction of exaggerated overbite in mixed dentition and describe a clinical case treated with this device. MTP favored the extrusion of posterior teeth, in addition to being shown to be a device that was easy to manufacture and effective in the treatment of excessive overbite, enabling patients to return to normal condition during the development of occlusion.

Evaluation of the cytotoxicity of latex and non-latex orthodontic separating elastics.

OBJECTIVE: To test the hypothesis that a difference in cytotoxicity exists between latex and non-latex orthodontic separating elastics. MATERIAL AND METHODS: Five intra-oral separating elastics from different manufactures (four latex and one non-latex) were divided into five groups of 15 elastics each: Group MA (non-latex elastics, Masel), Group MO (natural latex, Morelli), Group DE (natural latex, Dentaurum), Group TP (natural latex, TP Orthodontics) and Group UN (natural latex, Unitek). The cytotoxicity assay was performed using cell cultures (epithelial HEp-2 cells originating from human laryngeal carcinoma) that were submitted to the cell viability test with neutral red (dye-uptake) at 24, 48, 72 and 168 h. Analysis of variance (anova) with multiple comparisons and Tukey's test were employed (p < 0.05). RESULTS: The results showed no statistically significant differences between groups MA, DE, TP and UN in relation to Group CC (cell control) for experimental times of 24, 48 and 168 h (p > 0.05). Morelli, Dentaurum, TP Orthodontics and Unitek elastics induced a great amount of cell lyses at 72 h. CONCLUSION: One can demonstrate that the Masel elastic induced less cell lysis compared with other elastics, but all trademarks were found to be clinically biocompatible. CLINICAL RELEVANCE: Separating orthodontic elastics are used in the interdental subgingival region with the aim to separate the teeth for placement of orthodontic bands. However, latex has been known to cause allergy. As these materials are widely used in clinical orthodontics, care regarding the cytotoxicity of orthodontic elastics should be taken. Thus, clinically proven biocompatible materials should be acquired whenever possible.

Influence of malocclusion on social perceptions of adolescents at public and private schools.

OBJECTIVE: To determine whether malocclusion influences adolescents' perception when judging their colleagues from the aspects of athletics, social and health status, leadership and academic skills. METHODOLOGY: Front view photographs of the smile of eight adolescent volunteers (non-ideal smile) were altered to create an image with aligned teeth (ideal smile). Two parallel groups were programmed with the subjects' photographs. When the image of an ideal smile of one of the subjects appeared in one of the groups, the image of the non-ideal appeared in the other. Two hundred adolescents were evaluators, half of the students being from private and half from public schools. They classified the group images indicating their social perception with respect to skills in sports, leadership, academic activities, popularity and the health conditions of each subject. RESULTS: The majority of photographs of subjects with an ideal smile were evaluated as being better when compared with photographs of the non-ideal smile. The differences in the evaluations between the ideal and non-ideal smiles were significant for the perception of popularity, intelligence, leadership capability and health, differently from the performance in sports, as this aspect did not attain statistical relevance. CONCLUSIONS: Malocclusion has influence on the perception of adolescents of different social levels when judging youngsters with or without malocclusion from the aspects of athletics, social and health status, leadership and academic skills.

In vitro evaluation of insertion and removal torques of orthodontic mini-implants.

This study evaluated the influence of bone cortical thickness on the maximum torque required for insertion and removal of orthodontic mini-implants of different shapes. Five different types of orthodontic mini-implants were examined Cylindrical 1 (CYM), Cylindrical 2 (CYI) and Cylindrical 3 (CYT) Conical 1 (CON), Conical 2 (COS). Insertion and removal torque tests were performed in mini-pig medullary bone (8mm thick) and cortical bone 1, 2, 3 and 6mm thick. A digital torque meter measured the torque forces; the maximum values of insertion and removal were obtained (N/cm). There were no statistically significant differences between the different implants in the torque forces required for insertion and removal from medullary bone (P>0.05). During insertion into 1-2mm cortical bone, COS, CON and CYT had torque values statistically higher, but CON had higher torque values compared with the others when 3-6mm cortical bone was used (P<0.05). The removal torque values were significantly lower for CYM and CYI. Conical type mini-implants require a greater torque force for insertion and removal compared with cylindrical types. Torque values were directly related to cortical thickness.