Evaluation of polymerization shrinkage stress and cuspal strain in natural and typodont teeth.

To evaluate the polymerization shrinkage stress and cuspal strain (CS) generated in an artificial (typodont) and in a natural tooth using different resin composites. Twenty artificial and 20 extracted natural molars were selected. Each tooth was prepared with a 4x4 mm MOD cavity. The natural and typodont teeth were divided into four experimental groups (n=10), according to the resin composite used: Filtek Z100 (3M Oral Care) and Beautifil II LS (Shofu Dental). The cavities were filled using two horizontal increments and the CS (µS) was measured by the strain gauge method. Samples were sectioned into stick-shaped specimens and the bond strength (BS) (MPa) was evaluated using a microtensile BS test. Shrinkage stress and CS were analyzed using 3D finite element analysis. No difference was found between the type of teeth for the CS as shown by the pooled averages: Natural tooth: 541.2 A; Typodont model: 591.4 A. Filtek Z100 CS values were higher than those obtained for Beautifil II LS, regardless of the type of teeth. No statistical difference was found for the BS data. Adhesive failures were more prevalent (79.9%). High shrinkage stress values were observed for Filtek Z100 resin, regardless of tooth type. The CS of typodont teeth showed a shrinkage stress effect, generated during restoration, equivalent to that of natural teeth.

Development of a correction coefficient for radiographic evaluation of the alveolar bone crest: a pilot study.

OBJECTIVES: To analyze the differences in cusp height on radiographs, establishing proportional relationships between cusp and alveolar bone crest (ABC) measurements. The goal of this study was to develop a correction coefficient by considering this proportion. MATERIALS AND METHODS: Twenty-one artificial teeth, molars and premolars, and bovine ribs were used. Interproximal radiographs were taken with the aid of a positioner. The vertical angles used were: 0°, + 5°, and + 10°, and processed using three spatial resolutions measured in line pairs per mm (lp/mm): 20, 25 and 40. The Perio filter was applied to each image, in addition to the original one. Combinations of angle, resolution, and filter were made. Eighteen images were analyzed by three specialists, resulting in 252 measurements for each evaluator, totaling 756 measurements. RESULTS: The overall variability of the measurements can be explained mainly by the variation in tooth anatomy. The 0° 25 lp/mm Perio filter method was the closest one to the actual clinical scenario for both cusps and ABC. The correction factor managed to explain 71.45% of the errors. CONCLUSIONS: The variation in vertical angulation interferes with cusp and ABC measurements, and the angulation at 0º and spatial resolution of 25 lp/mm showed better results. The use of correction coefficients allowed approaching actual measurement values. CLINICAL RELEVANCE: More accurate ABC height measurements are essential even in radiographic exams that do not meet the standard of excellence because the need to repeat radiographic exams is then eliminated.

Effect of time and photoactivated face on bond strength of brackets and on degree of monomer conversion.

OBJECTIVE: To evaluate the effect of four different photoactivation protocols (according to "photoactivated faces" - mesial/distal, cervical/incisal or center - and "photoactivation time" - 6-3 s) of a high-power photo activator (Valo Cordless®-Ultradent) on the shear bond strength (SBS) between metal brackets and dental enamel and on the degree of conversion (DC) of an orthodontic resin. MATERIALS AND METHODS: 40 bovine incisor crowns were randomly assigned to 4 groups (n = 10). The brackets were bonded with Transbond XT® resin using 4 protocols according to the "photoactivation protocol" factor (which was subdivided into photoactivated faces and photoactivation time): V3C = 3 s + center; V6C = 6 s + center; V3M3D = 3 s on mesial + 3 s on distal; V3C3I = 3 s on cervical + 3 s on incisal. All the samples were stored for 4 months (water,37ºC) and then subjected to a SBS test (100KgF,1 mm/min). 40 resin discs were made to evaluate the monomer degree of conversion. Data from the SBS and DC were assessed by One-way ANOVA and Tukey's test (5%). Bond failures were analyzed according to the Adhesive Remnant Index (ARI) and evaluated by the Kruskal-Wallis test (5%). RESULTS: There was a statistically significant difference (p = 0.008) in the One-way ANOVA result for SBS values between all groups, but the protocols showed statistically similar results (p ≥ 0.05-Tukey's tests) concerning the photoactivated faces (V6C, V3M3D and V3C3I) and photoactivation time (V3C and V6C) factors individually. There was no statistically significant difference (p ≥ 0.05) in the One-way ANOVA result for DC values. CONCLUSION: The SBS and DC values will vary depending on the protocol applied. CLINICAL RELEVANCE: It is possible to maintain the bracket fixation quality with the use of a high-power LED photo activator associated with a shorter photoactivation time. However, it is assumed that not all types of protocols that might be applied will provide quality bonding, such as V3C, V3M3D and V3C3I, which may - depending on the SBS and DC values - affect the final treatment time, due to brackets debonding, or increase of possibility of damage to dental enamel during bracket removal. Clinical studies are suggested to confirm the hypotheses of this research.

Biomechanical impact of labiolingual diameter on endodontically treated anterior teeth with crown restoration under occlusal loading.

OBJECTIVE: To evaluate the effect of the labiolingual diameter and construction of an endodontically treated (ET) anterior tooth with crown restoration on stress distribution and biomechanical safety under occlusal loading. METHODOLOGY: Three-dimensional finite element models were generated for maxillary central incisors with all-ceramic crown restorations. The labiolingual diameters of the tooth, defined as the horizontal distance between the protrusion of the labial and lingual surfaces, were changed as follows: (D1) 6.85 mm, (D2) 6.35 mm, and (D3) 5.85 mm. The model was constructed as follows: (S0) vital pulp tooth; (S1) ET tooth; (S2) ET tooth with a 2 mm ferrule, restored with a fiber post and composite resin core; (S3) ET tooth without a ferrule, restored with a fiber post and composite resin core. A total of 12 models were developed. In total, two force loads (100 N) were applied to the crown's incisal edge and palatal surface at a 45° oblique angle to the longitudinal axis of the teeth. The Von Mises stress distribution and maximum stress of the models were analyzed. RESULTS: Regardless of the loading location, stress concentration and maximum stress (34.07~66.78MPa) in all models occurred in the labial cervical 1/3 of each root. Both labiolingual diameter and construction influenced the maximum stress of the residual tooth tissue, with the impact of the labiolingual diameter being greater. A reduction in labiolingual diameter led to increased maximum stress throughout the tooth. The ferrule reduced the maximum stress of the core of S2 models (7.15~10.69 MPa), which is lower compared with that of S3 models (19.45~43.67 MPa). CONCLUSION: The labiolingual diameter exerts a greater impact on the biomechanical characteristics of ET anterior teeth with crown restoration, surpassing the influence of the construction. The ferrule can reduce the maximum stress of the core and maintain the uniformity of stress distribution.

Nutritional supplementation, tooth crown size, and trait expression in individuals from Tezonteopan, Mexico.

Understanding how epigenetic factors impact dental phenotypes can help refine the use of teeth for elucidating biological relationships among human populations. We explored relationships among crown size, principal cusp spacing, and accessory cusp expression in maxillary dental casts of nutritionally supplemented (n = 34) and non-supplemented (n = 39) individuals from Tezonteopan, Mexico. We hypothesized that the non-supplemented group would exhibit smaller molar crowns and reduced intercusp spacing. Since intercusp spacing is thought to be more sensitive to epigenetic influences than crown size, we predicted that the supplemented and non-supplemented groups would differ more in the former than the latter. Previous work suggests that molar accessory cusp expression may be elevated under conditions of stress. We therefore expected evidence of greater Carabelli and Cusp 5 trait expression in the non-supplemented group. We further hypothesized that anterior teeth would be affected by nutritional stress during development, with the non-supplemented group having smaller anterior tooth crowns and therefore limited space to form the tuberculum dentale. Finally, we tested whether the presence of molar accessory traits followed predictions of the Patterning Cascade Model of tooth morphogenesis in the entire sample. Our results supported the expectation that cusp spacing would differ more than molar crown size between the two groups. Carabelli trait showed little evidence of frequency differences between groups, but some evidence of greater trait scores in the non-supplemented group. The non-supplemented group also showed evidence of greater Cusp 5 frequency and expression. In the central incisors and canines, there was strong evidence for smaller crown sizes and reduced tuberculum dentale frequency in the non-supplemented group. With both groups pooled together, there was strong evidence of closer mesiodistal distances among principal cusps in molars with accessory cusps, a finding that is consistent with the PCM. Overall, our findings suggest that nutritional stress may affect accessory cusp expression.

Comparative evaluation of three materials used for fragment reattachment in uncomplicated crown fracture-An in vitro study using bovine teeth.

BACKGROUND/AIMS: The recommended treatment for uncomplicated crown fractures is bonding the fractured fragment or the fragment reattachment. A paucity was identified regarding the studies comparing the efficacy of micro-hybrid and nanohybrid composites in fragment reattachment. Hence, the present study aimed to evaluate and compare three materials for bonding of fragments rehydrated by humidification in teeth with uncomplicated crown fractures. MATERIAL AND METHODS: Eighty mandibular bovine incisors with similar dimensions and free of any structural deformities were fractured similar to the technique followed in previous studies. Fracture was simulated, fragments, and stumps were coded, stumps were stored in artificial saliva and the fragments were dehydrated at room temperature and pressure. They were randomly assigned to Group-1 (no rehydration), Group-2 (rehydrated and bonded by flowable nanohybrid composite-3M Filtek Supreme Syringe Flowable Composite Resin-A2, Sao Paulo, Brazil), Group-3 (rehydrated and bonded by flowable micro-hybrid composite- Ruby Flow, InciDental, England, United Kingdom), and Group-4 (rehydrated and bonded by light-cured Glass-Ionomer-Cement-Voco Ionoseal, Cuxhaven, Germany). The samples were subjected to a universal testing machine to evaluate the force required to fracture the bonded fragments. RESULTS: The highest median value of the force required to fracture was recorded for Group 2 (208.4 N) followed by Group 3 (195.2). The force required to fracture the bonded fragments was lowest in Group 4 (67.2 N) which was lower than the negative control (131.4 N). The differences between the observations in Groups 2 and 3 were not found to be statistically significant. CONCLUSION: The nano and micro-hybrid composites showed greater force required to fracture than fragments bonded by LC-GIC. Dehydrated fragments bonded using nanocomposites performed better than rehydrated fragments bonded by using LC-GIC.

Benefits of Coronectomy in Lower Third Molar Surgery: A Systematic Review and Meta-analysis.

PURPOSE: The purpose of this study was to measure and compare coronectomy versus extraction in patients at increased risk for inferior alveolar nerve (IAN) injuries associated with third molar removal in terms of IAN injury and other complications. METHODS: The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist. We conducted a comprehensive literature search across six databases and the gray literature from July 15 to August 01, 2022. We employed Rayyan software to identify and remove duplicate articles to ensure data integrity. Our research followed the strategy patient (P), intervention (I), comparison (C), outcome (O), and study (S): (P) patients needing lower third molar surgery at higher risk of IAN injury; (I) surgery options, coronectomy or complete extraction; (C) comparisons included reduced risks of nerve injuries, postoperative complications (pain, infection, alveolitis), and increased risks of reoperation, root migration, and extraction; (O) desired outcomes were preventing nerve injuries and reducing other surgical complications; and (S) observational study designs (cohort, case-control). Excluded from consideration were studies involving teeth other than lower third molars, as well as reviews, letters, conference summaries, and personal opinions. To gauge the certainty of evidence, we employed the Grading of Recommendation, Assessment, Development, and Evaluation instrument, selecting the most current papers with the highest levels of evidence for inclusion. The primary outcome variable of our study centered on evaluating the incidence of IAN injury, and secondly, the lingual nerve (LN) injury, the postoperative pain, infection, localized alveolitis, the necessity for surgical reintervention, root migration, and extraction. These assessments were carried out with respect to their chosen operative technique for managing third molars, either coronectomy or extraction, as predictor variables. We also considered covariates such as age, gender, and the presence of systemic diseases in our analysis to account for potential confounding factors. The pooled data underwent rigorous analysis utilizing an inverse variance method with both random and fixed effect models by the "metabin" function in the R program's meta-package. Additionally, we assessed the risk of bias in the selected studies by utilizing the Joanna Briggs Institute's Critical Appraisal Checklist for Studies Reporting Prevalence Data and the Critical Appraisal Checklist for Case Reports. RESULTS: Of the 1,017 articles found, after applying the inclusion and exclusion criteria, 42 were included in this study (29 cohort and 13 case-control studies), including 3,095 patients from 18 countries. The meta-analysis showed that coronectomy reduced the risk of IAN injury [OR (Odds Ratio): 0.14; 95% CI (confidence intervals): 0.06-0.30; I2 (inconsistency index) = 0%; P = .0001], postoperative pain (OR: 0.97; 95% CI: 0.33-2.86; I2 = 81%; P = .01), and alveolitis (OR: 0.38; 95% CI: 0.13-1.09; I2 = 32.2%; P = .01) when compared to complete tooth extraction. However, it also highlighted a greater risk of reintervention (OR: 5.38; 95% CI: 1.14-25.28; I2 = 0.0%; P = .01). CONCLUSIONS: This study has demonstrated that coronectomy is associated with a decreased risk for IAN injury and decreased pain and localized alveolitis when compared to complete tooth extraction. However, it is essential to acknowledge the higher likelihood of requiring reintervention with coronectomy. Therefore, clinicians should carefully consider the advantages and potential drawbacks of both techniques and tailor their choices to the unique clinical circumstances of each patient.

Aesthetic Dentistry - What You Decided and What I Want: Shade Selection

ABSTRACT Objective: To assess the relationship between patients' and dentists' perceptions of shade selection and its impact on satisfaction with the prosthesis. Material and Methods: A single group pre-post study was conducted at the Prosthodontics department of a teaching hospital in India. One hundred ten participants were selected through a systematic random sampling technique with inclusion and exclusion criteria. Patients' attitudes regarding the aesthetics of their maxillary anterior teeth were recorded using a validated questionnaire. Shades for the intended prosthetic crown selected by the dentist and chosen by the patient were recorded separately, and patient satisfaction with the appearance of the final prosthesis was recorded. We used descriptive statistics followed by Pearson's Chi-square test and a binomial logistic regression model for inferential statistics. Results: 109 participant's data were available for final analysis. Patients choose lighter shades than the dentist's selection, which is statistically significant (p=0.000). 73.4% were satisfied with the final prosthesis, and the binomial logistic regression model identified using patient-selected shade for the final prosthesis was significantly associated with patients' satisfaction with the final prosthesis (OR=3.3, p=0.001). Conclusion: The patient's preference should be considered with the dentist's option when selecting a shade to create good esthetics.

Dimensional accuracy of provisional complete crown made by the 3D printing method / Acuidade dimensional de coroas totais provisórias confeccionadas pelo método de impressão 3D

Objective: This study evaluated the dimensional accuracy of provisional complete crowns printed with photopolymerizable resin using an LCD-type 3D printer through optical metrology, varying the printing angle and the number of complete crowns printed at once on a single-build platform. Material and Methods: The complete crowns were printed with temporary crown resin, A2 temporary (Wilcos do Brasil), divided into four groups with n=12: Group A - 3 complete crowns positioned at 150° on the x-axis; Group B - 4 complete crowns positioned at 150° on the x-axis; Group C - 3 complete crowns positioned at 180° on the x-axis; and Group D - 4 complete crowns positioned at 180° on the x-axis. Dimensional accuracy was assessed by overlaying images in the Gom Inspect measurement software, where the STL of each complete crown was aligned and compared to the master model. For statistical analysis, one-way ANOVA and Shapiro-Wilk tests were used. Results: No significant statistical difference was observed between the differentangles, or the number of complete crowns printed at once. Conclusion: Based on dimensional accuracy, the printing of provisional complete crowns with an LCD-type 3D printer shows no significant statistical difference with either the 150 or 180-degree angle variations, and there is also no difference when printing 3 or 4 complete crowns at once.(AU)

Objetivo: Este estudo avaliou a acuidade dimensional de coroas totais provisórias impressas com resina fotopolimerizável por uma impressora 3D tipo LCD por meio da metrologia optica, variando angulação de impressão e número de coroas impressas por vez em uma única plataforma de construção. Material e Métodos: As coroas foram impressas com resina para coroa provisória, A2 temporário (Wilcos do Brasil), divididas em quatro grupos com n=12: Grupo A - 3 coroas posicionadas a 150° no eixo x; Grupo B - 4 coroas posicionadas a 150° no eixo x; Grupo C - 3 coroas posicionadas a 180° no eixo x e Grupo D - 4 coroas posicionadas a 180° no eixo x. A acuidade dimensional foi feita com a sobreposição de imagens no programa de aferição Gom Inspect, em que o STL de cada coroa foi alinhado e comparado ao modelo mestre. Para análise estatística, foram utilizados os testes ANOVA um fator e Shapiro-Wilk. Resultados: Não foi verificada diferença estatística significativa entre as diferentes angulações ou quantitadade de coroas impressas em uma única vez. Conclusão: Com base na acuidade dimensional, a impressão de coroas provisórias com impressora 3D tipo LCD não apresenta diferença estatística significative com nenhuma das duas variações angulação de 150 ou 180 graus e não há diferença também ao fazer a impressão de 3 ou 4 coroas de uma única vez.(AU)

Tooth discoloration induced by endodontic sealers and cervical limit: 1-year in vitro evaluation.

This laboratory study aimed to evaluate the influence of endodontic sealer and cervical limit of root filling on the discoloration of root canal treated teeth. Bovine incisors were randomly distributed into six experimental groups and control (n=21/group), according to the endodontic sealer used [AH Plus (AP); MTA Fillapex (MF) and Sealer Plus BC (SPB)] and the cervical limit of root filling [dental cervix (DC) or 2 mm in apical direction (2mm-AD)]. Tooth discoloration (ΔE) was evaluated by a digital spectrophotometer using the CIED2000 method. Color assessments were performed immediately before (baseline), 1 week, 1, 3, 6 months, and 1 year after obturation. Data were analyzed by ANOVA and Tukey's post-hoc tests (α=5%). Teeth filled with the three sealers showed perceptible tooth discoloration (ΔE≥2.7) in 1 week, maintaining similar values over time. There was a significant difference between MF and SPB sealers in the 2mm-AD groups. In addition, 2mm-AD groups promoted significantly lower discoloration than DC groups for AH (3 months) and SPB (1 and 3 months) sealer,s. Teeth filled with AP, MF, and SPB sealers displayed discoloration from 1 week to one year, with differences between MF and SPB sealers. A cervical limit of filling material at 2 mm from the dental cervix seems more advisable, promoting lower crown discoloration.

Management of ankylosed teeth using the decoronation technique: integrative literature review and case report.

INTRODUCTION: The decoronation technique has been described in literature since 1984 and, based on the available results, it can lead to considerable benefits for the repair and rehabilitation of ankylosed teeth. Based on these reports, one could expect that this procedure would be well known by the dental community. However, this fact does not seem to be true, and this procedure is not widely used. METHODS: The objective of this paper is to present appropriate literature that discusses decoronation and evaluate the perspectives of the procedure, both in relation to the technique and the long-term benefits for the patient. An integrative literature review at PubMed, ScieELO, and Lilacs databases was performed using the keywords "decoronation", "ridge preservation decoronation", "decoronation ankylosis". In addition, a case report will be presented to demonstrate the technique in a systematic and detailed manner. RESULTS: Considering the inclusion criteria, 27 articles that present consistency regarding decoronation were selected. CONCLUSION: There is scarce availability of scientific works related to the topic, to corroborate and discuss the technique. The present paper reinforces the benefits of this procedure, and revisit decoronation, attempting to provide a possible treatment for ankylosed teeth in growing patients.

Use of dimensions in posterior dentition for sex estimation in forensic contexts: A systematic review and meta-analysis.

OBJECTIVE: This study assessed the validity of dimensions in posterior dentition for sex estimation in forensic contexts. DESIGN: A systematic review was established following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). After assessing the risk of bias and methodological quality with the QUADAS-2 system, the data were subjected to statistical tests for a meta-analysis of diagnostic accuracy and I2 to verify the heterogeneity. RESULTS: The search resulted in 15 studies that underwent qualitative testing, all were selected for quantitative analysis. The papers included: the mesiodistal of the upper first molar, lower first molar, and upper second molar, and the buccolingual of the upper first molar and upper second molar. The results showed that sensitivity and specificity rates were lower with the mesiodistal diameter, with rates of 0.577 for the lower first molar, 0.674 for the upper first molar, and 0.698 for the upper second molar, while the rates were higher with the buccolingual diameter, with 0.724 for the upper first molar, and 0.743 for the upper second molar. The power to estimate sex is greater for males than for females. High heterogeneity was detected among the studies of almost all dimensions, except sensibility for the lower first molar and specificity for the upper second molar. CONCLUSIONS: None of the dimensions reached an accuracy of ≥80%, however, so they are not a reliable method for sex estimation in forensic practice.

Tratamento de odontoma composto e cisto dentígero: relato de caso / Treatment of compound odontoma and dentigeral cyst: case report

Introdução: o odontoma é considerado como um frequente tumor odontogênico benigno, podendo ser classificado em tipo composto ou tipo complexo. O cisto dentígero é o mais comum entre os cistos odontogênicos de desenvolvimento, onde envolve a coroa da unidade dentária no nível da junção amelocementária. Há poucos estudos na literatura do encontro das duas lesões, acometendo o mesmo local na cavidade oral. O diagnóstico pode ser constituído por exame clínico e de imagem. Objetivo: apresentar um caso clínico de odontoma composto e cisto dentígero em região de parassínfise mandibular esquerda abordando as caraterísticas clínicas destas duas lesões e as adequadas formas de tratamento. Relato de caso: paciente do sexo masculino, 16 anos de idade, compareceu ao ambulatório do Centro Odontológico da Escola Bahiana de Medicina e Saúde Pública (Salvador, Bahia), portando encaminhamento de ortodontista, solicitando exodontia da unidade dentária 33 inclusa associada a um odontoma. Ao realizar exames físicos e imaginológicos detectou-se a hipótese diagnóstica de odontoma composto associado a unidade dentária, envolto em folículo pericoronário ou cisto dentígero. Foi realizada biópsia excisional das duas lesões e exodontia da unidade. A análise histopatológica confirmou o diagnóstico para odontoma composto associado a cisto dentígero na unidade 33. Ao acompanhamento de 03 meses, paciente apresentou neoformação óssea da região de parassínfise mandibular, mediante a análise de novos exames imaginológicos. Discussão: há poucos estudos na literatura da associação entre as duas lesões, porém relatos afirmam que o odontoma pode ser encontrado associado aos cistos odontogênicos. Por conta da falta de maiores estudos dessa associação, há escassez de recomendações terapêuticas de acordo com faixa etária e extensão do acometimento das lesões. Considerações finais: lesões comumente assintomáticas, tem o diagnóstico constituído por exame clínico e avaliação de exames de imagem(AU)

Introduction: odontoma is considered a frequent benign odontogenic tumor and can be classified as a compound or complex type. The dentigerous cyst is the most common among developmental odontogenic cysts, where it involves the crown of the dental unit at the level of the cementoenamel junction. There are few studies in the literature on the meeting of the two lesions, affecting the same site in the oral cavity. The diagnosis can be made by clinical and imaging examination. Objective: to present a clinical case of compound odontoma and dentigerous cyst in the left mandibular parasymphysis region, addressing the clinical characteristics of these two lesions and the appropriate forms of treatment. Case report: male patient, 16 years old, attended the outpatient clinic of the Centro Odontológico da Escola Bahiana de Medicina e Saúde Pública (Salvador, Bahia), having been referred by an orthodontist, requesting extraction of the included dental unit 33 associated with an odontoma. Upon physical and imaging examinations, the diagnostic hypothesis of a compound odontoma associated with a dental unit, surrounded by a pericoronal follicle or dentigerous cyst, was detected. Excisional biopsy of the two lesions and extraction of the unit were performed. The histopathological analysis confirmed the diagnosis of compound odontoma associated with dentigerous cyst in unit 33. At the 03-month follow-up, the patient presented bone neoformation in the mandibular parasymphysis region, through the analysis of new imaging exams. Discussion: there are few studies in the literature on the association between the two lesions, but reports state that odontoma can be found associated with odontogenic cysts. Due to the lack of further studies on this association, there is a lack of therapeutic recommendations according to age group and extent of lesion involvement. Final considerations: commonly asymptomatic lesions, the diagnosis consists of clinical examination and evaluation of imaging tests(AU)

On the first Baryonychinae (Theropoda, Spinosauridae) teeth from South America.

We report the first occurrence in South America of spinosaurid specimens belonging to the clade Baryonychinae. The material comprises three tooth crowns recovered from the Lower Cretaceous (Berriasian-Valanginian) of the Feliz Deserto Formation, State of Sergipe, northeast Brazil. The three specimens have the typical conidont condition, displaying a fluted morphology, veined enamel texture and carinae extending to the cervix region, conditions similar to those shared among spinosaurid theropods. Furthermore, a notable feature is the presence of a serrated carinae composed of 6-7 diminutive denticles per millimetre, a key feature shared by baryonychine spinosaurids. Phylogenetic and multivariate analyses performed on dentition-based and crown-based datasets of theropod taxa confirm the relationship of the three tooth crowns described here with the well-supported spinosaurid clade. Our results retrieve the taxa which comprise the "classically" baryonychine clade as individual branches within a polytomy which includes the three tooth crowns and a subclade of spinosaurines (Spinosaurus + Angaturama/Irritator). Additionally, the discriminant and cluster analyses suggest that the materials are more similar to Suchomimus than to Baryonyx morphometrically, but clearly bearing similarities with baryonychines (sharing a similar morphospace). These new findings paleogeographically expand the occurrence of this clade to western Gondwana, and comprise one of the oldest spinosaurid records worldwide, which brings implications on hypotheses for the emergence and evolution of the clade. Furthermore, these new records indicate the presence of more than one spinosaurid taxon in the Lower Cretaceous deltaic paleoenvironment of the Feliz Deserto Formation.

Impact of low intensity pulsed ultrasound on volumetric root resorption of maxillary incisors in patients treated with clear aligner therapy: A retrospective study.

OBJECTIVE: The aim of this study was to evaluate the volumetric root resorption in maxillary incisors following clear aligner therapy (CAT) with low-intensity pulsed ultrasound (LIPUS), and compare the results to CAT alone. MATERIAL AND METHODS: This retrospective study evaluated pretreatment (T0) and post-treatment (T1) cone-beam computed tomography imaging of 42 adult patients. Twenty-one patients (14 females, 7 males, mean age= 38.1±12.96 years) were treated using CAT with LIPUS device, whereas the other twenty-one matching controls patients (15 females, 6 males, mean age= 35.6±11.7 years) were treated using CAT alone. Images were analyzed and a segmentation protocol was applied on the maxillary incisors. Each segmented tooth volume was exported as a surface mesh in the Visualization Toolkit (VTK) file format. The VTK files for all maxillary incisors were coded and corresponding teeth volumes from T0 and T1 were superimposed. Clipping the crown of each tooth was done, then measurements of root volumes and differences between groups were performed. Changes in root volumes were assessed (p<0.05). RESULTS: Root loss was evident in all teeth in both groups, but was significantly increased in all maxillary incisors of the control group (p<0.001) and in upper left central incisor of LIPUS group (p=0.009). When both groups were compared, there was statistically significant minimal volumetric root loss in LIPUS group (3.50-7.32 mm3), when compared to control group (11.48-12.95 mm3) (p<0.05). CONCLUSION: LIPUS group showed less volumetric root resorption compared to control group during the studied treatment time using clear aligners.

Polymorphisms in hormonal-related genes might be associated with variations in permanent tooth crown size.

BACKGROUND: The variability in tooth crown size (TCS) is influenced by genetic factors and might be regulated by the difference in hormonal response. MATERIALS AND METHODS: This study aimed to evaluate the association between variations in TCS of permanent teeth with associated factors and genetic polymorphisms in hormonal-related genes (ESR1, ESR2 and PTH). This cross-sectional study involved dental casts from 86 individuals of both sexes. Dental casts were used to determine the maximum TCS of all fully erupted permanent teeth (except third molars) in the mesiodistal (MD) and buccolingual (BL) dimensions. Data such as sex, ethnicity, dental group (incisor, canine, premolar and molar), dental arch (upper and lower) and genetic polymorphisms of hormonal-related genes were used. The DNA from each patient was collected to evaluate the genetic polymorphisms in ESR1 (rs2234693 and rs9340799), ESR2 (rs1256049 and rs4986938) and PTH (rs694, rs6256 and rs307247) through real-time PCR. The data were submitted to statistical analysis with a significance level of 0.05. RESULTS: In the MD dimension, the sex, dental group and dental arch were associated with variation in TCS (P < .05). In the BL dimension, the sex, dental group, dental arch and polymorphism in rs694 and rs307247 were associated with variation in TCS. CONCLUSIONS: In short, this study suggests that genetic polymorphisms of PTH are associated with variations in the BL TCS of permanent human teeth.

Interdisciplinary treatment of ankylosed upper central incisors with an anterior vertical ridge defect: A case report.

This case report describes the successful 10-years interdisciplinary treatment of ankylosed upper central incisors with an anterior vertical ridge defect. This treatment was challenging as ankylosis was present before the growth spurt. Orthodontic treatment in association with decoronation, a xenogeneic bone graft, an autogenous sub-epithelial connective tissue graft, and implant placement were performed to correct the vertical ridge defect and to re-establish appropriate function, gingival health, and aesthetics. Decoronation performed during the growth spurt was the key to avoiding alveolar ridge deformity.

Conservative management of a horizontal root fracture in a primary maxillary central incisor: Case report.

Dental trauma occurs frequently in toddlers and the treatment protocols vary depending on each case. Thus, clinicians must not only plan the treatment but also consider any possible sequelae and characteristics related to the child and the family. The aim of this paper was to report a case of a three-year-old boy who had a horizontal root fracture in the middle third of the primary maxillary right incisor root (tooth 51) and crown discoloration of the primary maxillary left incisor (tooth 61) which were successfully treated with conservative management. The management was established in agreement with the family and was based on active surveillance. The clinical and radiographic follow-ups showed no changes besides pulp canal calcification of the left incisor throughout the eight years of follow-up. The pulps remained normal with no pathological signs throughout their life cycle and the permanent successors erupted normally, presenting an excellent result of the non-invasive approach adopted.

Acuidade dimensional de coroas totais provisórias confeccionadas pelo método de impressão 3D / Dimensional accuracy of full provisional crowns made by the 3D printing method

Atualmente, a impressão 3D, método de fabricação aditivo do sistema CAD/CAM, veio para implementar o conceito de customização em massa na odontologia: permite que uma grande quantidades de produtos personalizados sejam produzidos a custos relativamente baixos. Há, atualmente, uma gama de materiais utilizados para impressão 3D na odontologia, de acordo com suas indicações, porém, são necessários mais estudos detalhando o desempenho de materiais confeccionados por essa tecnologia, bem como a metodologia aplicada. Esse estudo teve como objetivo avaliar a acuidade dimensional de coroas totais provisórias impressas com resina fotopolimerizável por uma impressora 3D tipo LCD por meio da metrologia optica, variando angulação de impressão e número de coroas impressas por vez em uma única plataforma de construção. As coroas foram impressas com resina para coroa provisória, A2 temporário (Wilcos), divididas em quatro grupos com n=12: grupo A - 3 coroas posicionadas a 150° no eixo x; grupo B - 4 coroas posicionadas a 150° no eixo x; grupo C - 3 coroas posicionadas a 180° no eixo x e grupo D - 4 coroas posicionadas a 180° no eixo x. A acuidade dimensional foi feita com a sobreposição de imagens no programa de aferição Gom Inspect, em que o STL de cada coroa foi alinhado e comparado ao modelo mestre. Para análise estatística, foram utilizados os testes ANOVA um fator e Shapiro-Wilk. Com base na acuidade dimensional, a impressão de coroas provisórias com impressora 3D tipo LCD é mais precisa com angulação de 150 graus e não há diferença entre 3 e 4 coroas impressas por vez (AU)

Currently, 3D printing, additive manufacturing method of the CAD/CAM system, has come to implement the concept of mass customization in dentistry: it allows a large amount of personalized products to be produced at relatively low costs. There is currently a range of materials used for 3D printing in dentistry, according to their indications, however, more detailed studies are needed on the performance of materials made by this technology, as well as the applied methodology. This study aimed to evaluate the dimensional accuracy of full provisional crowns printed with photopolymerizable resin by an LCD-type 3D printer using optical metrology, varying printing angle and number of crowns printed at a time on a single construction platform. The crowns were printed with A2 temporary crown resin (Wilcos), divided into four groups with n=12: group A - 3 crowns positioned at 150° on the x axis; group B - 4 crowns positioned at 150° on the x axis; group C - 3 crowns positioned at 180° on the x axis and group D - 4 crowns positioned at 180° on the x axis. Dimensional acuity was performed by superimposing images in the Gom Inspect gauging program, in which the STL of each crown was aligned and compared to the master model. For statistical analysis, one-way ANOVA and Shapiro-Wilk tests were used. Based on dimensional accuracy, printing temporary crowns with LCD type 3D printer is more accurate with 150 degree angulation, and there is no difference between 3 and 4 crowns printed at a time. (AU)

Análise dos preparos e coroas totais em dissilicato de lítio, através do design auxiliado por computador / Analysis of preparations and full crowns in lithium disilicate, through computer-aided design

O dissilicato de lítio, se tornou popular para confecção de coroas dentárias devido às suas propriedades biomecânicas e compatibilidade biológica. O sucesso a longo prazo das restaurações depende de diversos fatores, entre eles, a espessura adequada da cerâmica e a ausência de áreas retentivas nos preparos dentais. O presente estudo baseia-se em uma análise exploratória de dados, e teve como objetivo analisar a presença de áreas retentivas nos preparos dentais e as espessuras das coroas totais em dissilicato de lítio, com intuito de identificar as faces do preparo com maior presença de áreas retentivas e as zonas de maior e menor susceptibilidade a fadiga precoce das restaurações. Um total de 100 preparos para coroas totais de molares superiores e inferiores, realizados por cirurgiões-dentistas, foram selecionados aleatoriamente e escaneados através de um scanner de bancada. O design das coroas totais cerâmicas foi realizado através do software Exocad (versão 2.2). Os arquivos em STL foram analisados por inspeção baseada em pontos, utilizando as ferramentas do Exocad. Para análise das espessuras do design da coroa, optou-se por secciona-las virtualmente em 3 cortes transversais e 3 longitudinais. A partir desses cortes realizou-se a mensuração de 54 pontos, após análise 50 pontos obtiveram relevância, esses foram divididos em 11 grupos, que representavam a faces: mesial, distal, vestibular, lingual e oclusal, os pontos foram distribuídos no terço oclusal, terço médio, terço cervical e oclusal das faces citadas, e comparados com a espessura ideal para se obter resistência adequada segundo a literatura. Através das análises estatísticas obteve-se como grupo de maior susceptibilidade a fadiga precoce da restauração o Grupo 3 (terço cervical da parede lingual), com 84,67% das amostras com a espessura inferior ao padrão para este grupo, seguido do Grupo 4 (terço cervical da parede vestibular) com 83,67% das amostras com a espessura inferior ao valor padrão. O Grupo 8 (terço oclusal e médio da parede distal) obteve a maior porcentagem das amostras satisfatórias, 86% obtiveram o valor igual ou acima do padrão, o Grupo 9 (terço oclusal e médio da parede mesial) apresentou 84,50% das amostras com valores iguais ou acima do valor padrão do grupo. Concluiu-se que, o terço cervical é a região com a maior susceptibilidade a fadiga precoce, e o terço oclusal e médio da distal a região com menor susceptibilidade a fadiga precoce. Para a análise dos preparos para as coroas utilizou-se a ferramenta do Exocad, Análise de Retenção, após a seleção do eixo de inserção da restauração, foi possível a visualização através de um gráfico de cor, que varia do azul ao vermelho para as áreas retentivas, como resultado, a face vestibular apresentou 27% dos preparos com necessidade de alívio, sendo a região com menor presença de áreas retentivas, porém a região distal apresentou necessidade de alívio em 40% dos casos, sendo a área com maior presença de retenção. Assim, a face distal dos preparos é a que mais apresentou áreas retentivas e a vestibular a face com menos zonas de retenção (AU)

The lithium disilicate has become popular for the fabrication of dental crowns due to its biomechanical properties and biological compatibility. The long-term success of restorations depends on various factors, including the appropriate thickness of the ceramic and the absence of retentive areas in dental preparations. This study is based on an exploratory data analysis and aims to analyze the presence of retentive areas in dental preparations and the thickness of lithium disilicate full crowns. The goal is to identify the preparation surfaces with a higher presence of retentive areas and the zones with greater and lesser susceptibility to early fatigue of the restorations. A total of 100 preparations for full crowns of upper and lower molars, performed by dentists, were randomly selected and scanned using a benchtop scanner. The design of the ceramic full crowns was carried out using Exocad software (version 2.2). The STL files were analyzed through point-based inspection using Exocad tools. For the analysis of crown design thickness, they were virtually sectioned into 3 transverse and 3 longitudinal cuts. Fifty relevant points were measured, divided into 11 groups representing the surfaces: mesial, distal, vestibular, lingual, and occlusal. These points were distributed in the occlusal, middle, cervical, and occlusal thirds of the mentioned surfaces and compared with the ideal thickness to achieve adequate resistance according to the literature. Through statistical analyses, the group with the highest susceptibility to early fatigue of the restoration was identified as Group 3 (cervical third of the lingual wall), with 84.67% of samples having thickness below the standard for this group. Group 4 (cervical third of the vestibular wall) followed closely, with 83.67% of samples having thickness below the standard. Group 8 (occlusal and middle thirds of the distal wall) showed the highest percentage of satisfactory samples, with 86% achieving or exceeding the standard value. Group 9 (occlusal and middle thirds of the mesial wall) presented 84.50% of samples with values equal to or above the standard for the group. It was concluded that the cervical third is the region with the highest susceptibility to early fatigue, and the occlusal and middle thirds of the distal region have the least susceptibility to early fatigue. For the analysis of crown preparations, the Exocad tool, Retention Analysis, was utilized. After selecting the restoration insertion axis, visualization through a color chart, ranging from blue to red for retentive areas, revealed that the vestibular surface showed 27% of preparations requiring relief, representing the region with the least presence of retentive areas. Conversely, the distal region required relief in 40% of cases, making it the area with the highest retentive presence. Thus, the distal surface of preparations exhibited the most retentive areas, while the vestibular surface had the fewest retention zones.(AU)