Dimensions of Occlusoproximal Cavitated Carious Lesions as a Cut-Off Point for Restorative Decision in Primary Teeth

ABSTRACT Objective: To investigate whether the dimensions of cavitated dentin carious lesions on the occlusoproximal surfaces of primary teeth could predict the location of cement-enamel junction (CEJ). Material and Methods: Two hundred extracted primary molars were selected and digital images were obtained. The teeth were set in arch models for clinical measurement. The cervical-occlusal (CO) and buccal-lingual/palatal (BL/P) cavities' dimensions were obtained by digital (Image J) and clinical (periodontal millimeter probe) assessments. The cervical margin location was also determined. The thresholds (cut-off points) were determined by sensitivity, specificity and the areas under the receiver operating characteristics curves (Az) for the two methods. Pearson's correlation coefficient was used to investigate the correlation between clinical and digital measurements. Logistic regression analysis was performed to evaluate the association between the dimensions and cervical margin location. Results: There was a strong correlation between methods for all measurements (CO: r=0.90, VL/P: r=0.95). Cavities with BL/P distance higher than 4.5 mm and CO dimension higher than 3.5 mm had a lower chance of presenting the cervical limit above the CEJ, irrespective of the measurement method. Conclusion: CO and VL/P dimensions could be used to predict the CEJ location and, ultimately, as a clinical parameter for restorative decision-making.

Accuracy of cone-beam CT in detecting vertical root fractures in teeth with post-endodontic restorations: an in vitro study

The aim of this study was to evaluate the accuracy of cone-beam CT (CBCT) for the detection of artificially created vertical root fractures (VRF) in extracted teeth restored with metallic (MP) and fiberglass (FGP) posts. After root canal obturation, 60 extracted human premolars were scanned by using the highest-resolution settings of a CBCT unit. Theprepared roots were randomly divided into three groups: group C (control group): non-restored and non-endodontically treated teeth (n = 20); group MP (n = 20); group FGP (n = 20). In all groups, 10 teeth were artificially fractured. Two external and independent observers blindly recorded the presence or absence of VRF. Sensitivity, specificity, accuracy, intra-and interobserver agreement were calculated. Kappa value for inter-and intraobserver agreement was 0.82 and 0.84 respectively, demonstrating goodagreement. The highest values for sensitivity (0.80 -0.90), specificity (1.00) and accuracy (0.90 -0.95) were found in the control group. The teeth with FGP restoration presented the lowest sensitivity (0.30 -0.50) and accuracy (0.60 -0.65) values. Both examiners had a good performance in the diagnosis of fractures in teeth with MP, with accuracy ranging between 0.85 -0.90. The presence of MP did not influence accuracy; however, the presence of FGP reduced the diagnostic capacity of CBCT.

The potential effect of instrumentation with different nickel titanium rotary systems on dentinal crack formation-An in vitro study.

The potential mechanical impact of different rotary systems used for root canal preparation has been a matter of debate for long. The aim of this study was to explore the incidence of dentinal cracks after root canal instrumentation with various rotary systems, in vitro. One hundred and eighty intact lower central incisors were selected and randomly divided into fourteen treatment groups (n = 12/group) and a control group (n = 12). After decoronation, the root canals were instrumented with fourteen different rotary systems (E3, E3 azure, NT2, Hyflex CM, Hyflex EDM, 2Shape, OneCurve, ProTaper Next, ProTaper Gold, WaveOne Gold, Mtwo, Reciproc Blue, TF adaptive, K3XF). All roots were horizontally sectioned at 3, 6, and 9 mm from the apex with a low-speed saw under water-cooling. The slices were then examined under stereomicroscope for dentinal cracks. No cracks were found in the control group. Cracks were found in all treatment groups, predominantly in the 3 mm slices. There was no statistically significant difference in the number of cracks when comparing the different systems to each other at any section level. At 3 mm, however, five of the studied systems, namely K3XF (p = 0.004), Protaper Next (p = 0.001), Reciproc Blue (p<0.001), TF adaptive (p = 0.050), and 2Shape (p = 0.009) presented a significantly higher number of cracks than the control group. Within the limitations of this study, instrumented canals presented dentinal cracks, while uninstrumented ones presented no cracks after sectioning. There seems to be no significant difference among the tested systems regarding crack formation in the instrumented root canal wall. Crack formation occurred irrespective of the motion of the rotary system (rotational or reciprocation). Further studies are needed to clarify the factors that contribute to crack formation in the case of each individual rotary system.

Odontología deportiva y prevención de trauma dentoalveolar / Sports dentistry and prevention of dentoalveolar traumas

La odontología deportiva es la rama de la medicina deportiva que se ocupa de la prevención y el tratamiento de las lesiones bucodentales y las enfermedades orales asociadas al deporte y el ejercicio. Por lo que se hace necesario la intervención de profesionales de la salud bucodental para hacer evaluaciones del deportista y el deporte que practica para ver los riesgos que puede tener de desarrollar y sufrir lesiones bucodentales como traumas dentoalveolares y lesiones no cariosas. Y de este modo realizar las recomendaciones a cada paciente que practica deporte, de los elementos que deben usar como equipamiento bucodental para evitar o reducir el daño dentoalveolar (AU)

Sports dentistry is the branch of sports medicine that deals with the prevention and treatment of oral injuries and oral diseases associated with sports and exercise. Therefore it is necessary the intervention of oral health professionals to make evaluations of the athlete and the sport he practices to see the risks that may have to develop and suffer oral injuries such as dentoalveolar trauma and non-carious lesions. And in this way make the recommendations to each patient who practices sports, of the elements that should be used as oral equipment to avoid or reduce dentoalveolar damage (AU)

Effect of aging on dentinal crack formation after treatment and retreatment procedures: a micro-ct study

Abstract In order to evaluate the volume of dentinal cracks taking into account the age of the dentin and the type of file system used for endodontic procedures, forty freshly extracted single-rooted lower incisive teeth presenting similar root volume, were divided into two groups according to the age of the patient: Group Young (18 - 30 years old) and Group Old (60 years old or more). Each specimen was scanned by microcomputed tomography (micro-CT) in three stages: (i) before any treatment, (ii) after endodontic treatment with Reciproc files (REC), and (iii) after subsequent endodontic retreatment. Each group was subdivided into two subgroups, according to the retreatment technique used: retreatment with REC or with ProTaper Universal Retreatment (PUR) files. For each subgroup, the images were analyzed for differences in the volume of dentinal cracks in the middle and apical thirds of the teeth , according to the dentin age. In both stages (before and after instrumentation), the micro-CT images of the old root dentin presented with higher volume of cracks than those of the young root dentin, statistical significance notwithstanding (p>0.01). The use of REC files appeared to have no statistically significant differences in the generation of cracks in any type of root dentin when compared with PUR files (p>0.01). When retreated with PUR, the old root dentin presented with a significantly higher volume of cracks (p<0.01) when compared with the old root dentin initially.

Resumo Para avaliar o volume de fissuras dentinárias levando em consideração a idade da dentina e o tipo de sistema de limas utilizadas para procedimentos endodônticos, 40 dentes unirradiculares, incisivos inferiores, apresentando similar volume radicular, recentemente extraídos foram divididos em dois grupos de acordo com a idade do paciente: Grupo Jovem (18 a 30 anos) e Grupo Idoso (60 anos ou mais). Cada espécime foi scaneada por microtomografia computadorizada (micro-CT) em três estágios: (i) antes de qualquer tratamento, (ii) após tratamento endodôntico com limas Reciproc (REC) e (iii) após subsequente retratamento endodôntico. Cada grupo foi subdividido em dois subgrupos, de acordo com a técnica de retratamento utilizada: retratamento com REC ou com lima ProTaper Universal Retreatment (PUR). As imagens foram analisadas quanto às diferenças no volume das fissuras dentinárias nos terços médio e apical dos dentes de acordo com a idade da dentina. Em ambos os estágios (antes e depois da instrumentação), as imagens de micro-CT da dentina radicular idosa apresentaram maior volume de trincas do que as jovens, sem significância estatística (p>0.01). O uso das limas REC mostram não ter diferença estatística significante na geração de fissuras, em qualquer tipo de dentina, quando comparadas às limas PUR (p>0.01). Quando retratada com PUR, a dentina radicular idosa apresentou um volume de trincas significativamente maior (p<0.01) quando comparado com a dentina radicular idosa inicialmente.

Periapical Microsurgery: Do Root Canal-retreated Teeth Have More Dentinal Defects?

INTRODUCTION: This microsurgical clinical study evaluated if teeth that have undergone endodontic retreatment are associated with more dentinal defects than primary root canal-treated teeth. METHODS: One hundred fifty-five patients who underwent periapical microsurgery treatment in a private practice setting were evaluated. The root ends were resected, and the roots were inspected for the presence of dentinal defects through the surgical operating microscope with the help of a 0.8-mm-diameter light-emitting diode probe light and methylene blue dye. The root canal treatment history (primary vs retreatment) of the teeth was documented and related to the presence or absence of dentinal defects. Bivariate analysis was performed using the chi-square test, and a multivariate analysis was performed using logistic regression to evaluate possible confounding effects of patient age, sex, and tooth location on the association between treatment and the presence of dentinal defects. RESULTS: Of the 155 treated teeth, 33 were excluded (3 fractured and 30 missing treatment history). Of the remaining 122 included teeth, 73 (59.8%) had undergone primary root canal treatment and 49 (40.2%) retreatment. Sixteen teeth (22.5%) of the primary root canal group versus 33 (64.7%) of the retreatment group had dentinal defects. The proportion of retreated teeth with dentinal defects compared with primary treatment was statistically significant (P < .001) with a higher proportion of retreated teeth having dentinal defects. In the multivariate analysis, only the type of treatment was statistically significant (P < .001). CONCLUSIONS: This clinical study showed that root canal-retreated teeth are associated with more dentinal defects than primary root canal-treated teeth.

Effect of Low-Intensity Pulsed Ultrasound on the Expression of Calcium Ion Transport-Related Proteins during Tertiary Dentin Formation.

Low-intensity pulsed ultrasound (LIPUS) is known for its positive effect on bone healing and reparative regeneration. This study investigated whether LIPUS affects reparative progression of the tooth and the expression of calcium ion transport-related proteins in odontoblasts and dental pulp cells using a rat dentin-pulp complex injury model. Forty male adult Sprague-Dawley rats underwent cavity preparation in the right maxillary first molar: 20 received LIPUS irradiation on the cavity-prepared tooth; 20 received LIPUS irradiation on the left maxillary first molar. Rats were randomly allocated into four groups: blank control group, LIPUS group, cavity-prepared group, cavity-prepared + LIPUS group. LIPUS irradiation (frequency: 1.5 MHz, 200-µs pulse width, 1-kHz pulse repetition frequency, 30 mW/cm2 spatial averaged temporal averaged intensity) was administered individually for 20 min daily. Rats were sacrificed 1, 3, 7 and 14 d post-operation. The histopathological and cellular morphologic changes in the dentin-pulp complex were detected with hematoxylin and eosin staining. Expression of calcium ion transport-related proteins (Cav1.2, NCX1 and TRPV1) was determined with immunohistochemical staining and imaging analysis. Histopathological analysis revealed obvious reparative dentin formation at day 14 in the cavity-prepared + LIPUS group compared with the other groups. Expression levels of Cav1.2, NCX1 and TRPV1 increased significantly by 22%, 53% and 23%, respectively, at day 1 and increased significantly by 23%, 27% and 22%, respectively, at day 3 in the cavity-prepared + LIPUS group (p <0.05) compared with the cavity-prepared group. LIPUS has a positive effect on the expression of calcium transport-related proteins during early-stage dentin injury and facilitates tertiary dentin formation; the mechanism for this likely relates to the inflammatory reaction and a mechanical effect.

Formação de biofilmes monotípicos e heterotípicos por Enterococcus faecalis E Enterococcus faecium em dentina radicular / Formation of monotypic and heterotypic biofilm by Enterococcus faecalis E Enterococcus faecium in root dentin

E. faecalis e E. faecium possuem grande relevância nas infecções hospitalares por apresentarem facilidade em adquirir resistência aos antibióticos. E. faecalis também apresentam alta prevalência nas infecções endodônticas, entretanto a importância de E. faecium para a odontologia ainda precisa ser esclarecida. Assim, o objetivo desse estudo foi comparar cepas clínicas de E. faecium com as cepas de E. faecalis em relação a capacidade de formação de biofilme na dentina radicular e penetração nos túbulos dentinários. Além disso, foi avaliada a interação dessas espécies em biofilmes mistos. Para a realização desse estudo, foram utilizadas cepas clínicas, previamante, isoladas de canais radiculares com infecções endodõnticas e identificadas pelo PCR multiplex. Entre as cepas isoladas, foram selecionadas 4 cepas de E. faecalis e 2 cepas de E. faecium. Primeiramente, foi realizado a formação dos biofilmes monotípicos das cepas de E. faecalis e E. faecium sobre dentinas radiculares de dentes bovinos. Os biofilmes foram formados em placas de microtitulação por diferentes tempos: 2, 4, 6, 24, 48, 72, 96 e 120 horas. Os biofilmes formados foram, então, analisados pela contagem de células viáveis (UFC/mL) e quantificação da biomassa total (método do cristal violeta). Além disso, os biofilmes foram analisados por Microscopia Eletrônica de Varredura (MEV) procurando-se observar a penetração das células de E. faecalis e E. faecium nos túbulos dentinários. A seguir foram formados biofilmes heterotípicos de E. faecalis e E. faecium para estudo das interações ecológicas estabelecidas entre as espécies. A análise dos biofilmes heterotípicos foi feita pela quantificação da biomassa total (cristal violeta) procurando-se detectar a presença de relações sinérgicas ou antagônicas. Os resultados foram submetidos à Análise de Variância (ANOVA) e teste de Tukey, considerando-se nível de 5%. Os resultados obtidos na contagem de UFC/mL dos biofilmes monotípicos, revelaram que as 6 cepas testadas apresentam grande capacidade para formar biofilmes na dentina radicular, alcançando valores de UFC/mL entre 8 a 12 log de acordo com o tempo de observação. Em relação a análise das imagens de MEV, as cepas clínicas de E. faecalis e E. faecium demonstraram capacidade semelhante para formar biofilmes e penetrar nos túbulos dentinários. Na comparação da quantificação da biomassa dos biofilmes monotípicos e heterotípicos, observamos que a interação das cepas clínicas E. faecalis e E. faecium favoreceu a adesão e crescimento do biofilme. Assim, concluiuse que as cepas de E. faecalis e E. faecium apresentam a mesma capacidade de formar biofilmes sobre a superfície radicular. Além disso, em biofilmes mistos, essas duas espécies estabelecem relações ecológicas sinérgicas, aumentando significativamente a formação de biofilmes(AU)

E. faecalis and E. faecium have a high relevance in hospital infections because they are easy to acquire resistance to antibiotics. E. faecalis also present high prevalence in endodontic infections, however the importance of E. faecium for dentistry still needs to be clarified. Thus, the objective of this study was to compare clinical strains of E. faecium with strains of E. faecalis in relation to the capacity of biofilm formation in root dentin and penetration into the dentin tubules. In addition, the interaction of these species in mixed biofilms was evaluated. In order to perform this study, clinical strains were used, pre-determined, isolated from root canals with endodontic infections and identified by multiplex PCR. Among the isolated strains, 4 strains of E. faecalis and 2 strains of E. faecium were selected. Firstly, the formation of the monotypic biofilms of the strains of E. faecalis and E. faecium on root dentin of bovine teeth was carried out. The biofilms were formed in microtiter plates at different times: 2, 4, 6, 24, 48, 72, 96 and 120 hours. The biofilms formed were then analyzed by counting viable cells (CFU / mL) and quantification of total biomass (violet crystal method). In addition, the biofilms were analyzed by Scanning Electron Microscopy (SEM), aiming to observe the penetration of E. faecalis and E. faecium cells into the dentin tubules. Then, heterophilic biofilms of E. faecalis and E. faecium were formed to study the ecological interactions established between the species. The analysis of the heterotypic biofilms was made by quantifying the total biomass (violet crystal) in order to detect the presence of synergistic or antagonistic relationships The results were submitted to Analysis of Variance (ANOVA) and Tukey test, considering a level of 5%. The results obtained in the CFU / mL count of the monotypic biofilms revealed that the six strains tested had a great capacity to form biofilms in the root dentin, reaching values of CFU / mL between 8 and 12 log according to the time of observation. In relation to SEM images, the clinical strains of E. faecalis and E. faecium demonstrated similar capacity to form biofilms and to penetrate the dentinal tubules. In the comparison of the biomass quantification of the monotypic and heterotypic biofilms, we observed that the interaction of the clinical strains E. faecalis and E. faecium favored the adhesion and growth of the biofilm. Thus, it was concluded that strains of E. faecalis and E. faecium have the same ability to form biofilms on the root surface. In addition, in mixed biofilms, these two species establish synergistic ecological relationships, significantly increasing the formation of biofilms(AU)

Avaliação da interface adesiva em dentina sadia e afetada por cárie sob pressão pulpar simulada e após desafio em solventes / Evaluation of sound and caries-affected dentin interface under simulated pulpal pressure and aging in food-simulating solvents

O objetivo deste estudo foi avaliar a resistência de união (RU) e características da interface adesiva em dentina sadia e afetada por cárie, na presença de pressão pulpar simulada e após desafio em solventes. Setenta e dois molares humanos hígidos (SD) e outros trinta e seis molares humanos cariados (NCAD) foram seccionados para obtenção de 2 mm de espessura de dentina, a partir do corno pulpar mais alto. Dentre as amostras sadias, trinta e seis foram submetidas à formação artificial de dentina afetada por cárie pelo processo de ciclagem de pH (ACAD). Previamente ao procedimento restaurador, a análise química da superfície oclusal de cinco amostras de cada dentina foi avaliada em espectroscopia de infravermelho por Transformada de Fourier (FTIR) e microdureza de superfície (KHN). Todas as amostras foram tratadas, sob pressão pulpar simulada (20 cm H20), sequencialmente com: ácido fosfórico 37%, sistema adesivo (Scotchbond Universal, 3M/ESPE), fotopolimerização (10 s), confecção de um bloco de resina composta (Filtek Z350 XT; 3M/ESPE) e fotopolimerização (20 s). Após 48 h, palitos retangulares de resina-dentina (1mm2) foram obtidos e aleatoriamente divididos em grupos, de acordo com o tempo de envelhecimento (24 h e 30 dias) e solventes: água deionizada (A), etanol a 99% (E) e metiletilcetona (MEK). As amostras foram submetidas aos testes de resistência adesiva à microtração (0,5 mm/min; 10 kgf), e a interface adesiva avaliada em microscopia eletrônica de varredura (MEV). Os sistemas adesivos foram avaliados frente ao desafio dos solventes, por análise da resistência flexural (RF), módulo de elasticidade (ME), sorção (SO) e solubilidade (SL). Os resultados de RU foram submetidos aos testes ANOVA de medidas repetidas sob 3-fatores (dentina, solvente e tempo de armazenamento), seguido do teste de múltiplas comparações de Tukey (p<0,05). FTIR: diferenças químicas foram observadas entre os substratos, pela perda do conteúdo mineral na NCAD (maior) e ACAD (intermediário) em relação à SD. KHN: NCAD mostrou as menores médias, diferindo significantemente da SD. RU: dentina, tempos, interação dentina-tempo e interação dentina-tempo-solvente mostraram efeitos estatisticamente significantes: SD apresentou diferenças significativas quando armazenada 24 h em A; diferenças significantes foram observadas no grupo NCAD para o solvente E após 30 dias. MEV: as características da interface adesiva diferiram entre os substratos e solventes: A degradou a interface entre dentina e camada de sistema adesivo; E e MEK entre camada de adesivo e resina composta. RF/ME: solvente e tempo foram estatisticamente significantes, com as menores médias para E. SO/SL: A apresentou as menores médias, diferindo significantemente dos demais solventes. Pode-se concluir que o tipo de dentina, o solvente e o tempo de armazenamento interferiram negativamente nos valores de RU, com as menores médias para: NCAD, E em 30 dias; e, as propriedades físico-mecânicas do sistema adesivo foram diretamente afetadas pelo E.(AU)

The aim of this study was to evaluate the bond strength (BS) and adhesive interface characteristics of sound and caries-affected dentin under presence of simulated pulpal pressure (SPP) and after aging in solvents. Seventy-two sound human molars (SD) and thirty-six caries-affected human molars (NCAD) were sectioned to obtain 2-mm dentin thickness from the highest pulp horn. Among the sound dentin samples, thirtysix were submitted to artificial formation of caries by the pH cycling (ACAD). Prior to restorative procedures, chemical analysis of the dentin occlusal surface of five selected samples was performed in Fourier transform infrared spectroscopy (FTIR) and surface microhardness (KHN). All samples were treated, under simulated SPP (20 cm H20), sequentially with: 37% phosphoric acid, adhesive system (Scotchbond Universal, 3M/ESPE), light-cured (10 s), a composite resin build up (Filtek Z350 XT; 3M/ESPE) and light-cured (20 s). After 48 h, tooth-resin sticks (1mm2) were obtained and randomly divided into groups, according to storage time (24 h and 30 days) and solvents: deionized water (W), 99% ethanol (E) and methyl ethyl ketone (MEK). Samples were submitted to microtensile bond strength test (0.5 mm/min; 10 kgf), and the adhesive interface was evaluated by scanning electron microscopy (SEM). The adhesive system was evaluated, against the solvents challenge, by flexural strength (FS), modulus of elasticity (ME), sorption (SO) and solubility (SL). Data were submitted to 3-way ANOVA (dentin, solvent and storage times) followed by Tukey (p<0.05). FTIR: Chemical differences in dentin were observed through mineral content loss in NCAD (higher) and ACAD (intermediate) in relation to SD. KHN:NCAD showed the lowest mean, differing significantly from SD. BS: Dentin, time, interaction dentin-time and interaction dentin-time-solvent had a statistically significant effect: SD showed significant differences when storage 24h in W; statistically significant differences were observed in group NCAD storage 30 days in E. SEM: the characteristics of adhesive interface differs among substrates and aging solvents: W degradated the interface between dentin and adhesive; E and MEK between adhesive and composite resin. FS/ME: solvent and time were statistically significant, with the lowest mean for E. SO/SL: A showed lower means, differing significantly from the other solvents. It can be concluded that the type of dentin, aging solvents and storage time interfered negatively on BS values, with lowest values for: NCAD, E for 30 days; and the physico-mechanical adhesive properties were directly affected by E.(AU)

Sistema adesivo universal: análise da interface adesiva e degradação colagenolítica em dentina submetida à diferentes protocolos de condicionamento ácido / Universal adhesive system: analysis of adhesive interface and collagenolytic degradation of demineralized dentin submitted to different acid etching ptotocols

O objetivo desse estudo foi analisar a interface adesiva do sistema adesivo Single Bond Universal (SBU) em dentina submetida à diferentes protocolos de condicionamento ácido em 24 h e 12 meses. E a degradação colagenolítica (DC) mediada por metaloproteinases (MMPs) e Catepsina-K (CAT-K) em tempo imediato. Esse estudo foi conduzido em 3 etapas: 1) Caracterização química da dentina em FTIR; 2) DC por meio de fragmentos do Telelopeptídeo Carboxiterminal do Colágeno Tipo I (ICTP) e do Terminal C do Telopeptídeo ligado ao Colágeno Tipo I (CTX) e a resistência à tração (RT) da do colágeno; 3) Análise da interface adesiva através da resistência de união (RU), análise de fratura, microscopia eletrônica de varredura (MEV) e nanoinfiltração (NI). Para FTIR foram utilizados 6 discos de dentina, divididos em 2 grupos: 1) Ácido fosfórico 32 %15 s (AF), 2) Ácido poliacrílico 25 % 10 s (AP). Para análise da DC, 12 discos de dentina foram completamente desmineralizados e divididos em 3 grupos: 1) AF, 2) AP e 3) Água deionizada (Controle) 15 s. Após, foram incubados e armazenados por 1 semana. Seguindo-se a análise da concentração de proteína total (PT). 50 µl da solução de incubação foram utilizadas para analisar ICTP e CTX. As concentrações foram calculadas em relação à PT. Para RT, foram testados 36 palitos obtidos dos discos de colágeno. Para RU foram utilizados 48 dentes, divididos em 2 grupos, de acordo com o período de armazenamento, divididos em três subgrupos: 1) AF, 2) AP e 3) Autocondicionante SBU 20 s (SE). Os dentes foram restaurados e armazenados em água destilada 37 °C. Após, foram submetidos ao teste de microtração e análise de fraturas. Para as análises MEV e NI foram utilizados 2 espécimes de cada subgrupo. Para análise estatística utilizou-se ANOVA 1-Fator, ANOVA- 2 Fatores e teste de Tukey (α=0.05). Para FTIR, AF reduziu a quantidade de fosfato e carbonato quando comparado ao AP. Para DC, a liberação de ICTPPT para AF foi significantemente maior do que para AP (p < 0,05). Não houve diferença na liberação de CTXPT para AF e AP (p > 0,05). Para RT não houve diferença entre AP e Controle, porém, apresentaram valores maiores do que AF (p<0,05). Para RU em MPa, não houve diferença estatisticamente significativa para todos os tratamentos nos diferentes períodos de análise (p < 0,05). A análise de fraturas evidenciou a predominância de fraturas adesivas e mistas. MEV mostrou melhor qualidade da interface após 12 meses para AF e AP. Após 12 meses apenas SE não apresentou NI. Assim sendo, o autocondicionamento ainda parece ser a melhor opção para sistemas adesivos universais que possuam monômeros funcionais em sua composição.(AU)

The aim of this study was to analyze the adhesive interface of the Single Bond Universal (SBU) to dentin submitted to different acid etching protocols in 24 h and 12 months, and the collagenolytic degradation (CD) by matrix metalloproteinases (MMPs) and Cathepsin-K (CAT-K) in the immediate time. This study was divided into three stages: 1) Dentin chemical characterization by FTIR; 2) CD by release of the collagen telopeptide fragment cross-linked carboxyterminal telopeptide of type I collagen (ICTP), and C-terminal crosslinked telopeptide of type I collagen (CTX) and ultimate tensile strength (UTS); 3) Analysis of the adhesive interface by microtensile bond strength (µTBS), failure mode, scanning electron microscopy (SEM) of the AI, and nanoleakage by SEM (NL). For FTIR, six dentin disks were divided into two groups: 1) Phosphoric acid 15 s (PA), 2) Polyacrylic acid 10 s (PAA). For CD twelve dentin disks were completely demineralized, then were divided into 3 groups 1) PA, 2) PAA, and 3) deionized water (Control) for 15 s. All disks were incubated in a buffered solution (BS) for 1 week. Total protein (TP) concentrations were measured using Nanodrop™ at 280 nm. 50 µl of BS was used to analyze solubilized telopeptide fragments using ICTP and CTX . ICTP and CTX average ratios were calculated in relation to TP concentration (ICTPtp and CTXtp). For UTS, 36 dentin beams obtained from collagen disks were tested. For µTBS, forty-eight teeth were divided into two groups according to the period of storage, then subdivided into three subgroups: 1) PA, 2) PAA, and 3) Self-etch 20 s (SE). After, composite build up, the specimens were stored in distilled water at 37 °C. Two specimens of each group were used for SEM analysis of AI and NL. Data were analyzed by one-way ANOVA, two-way ANOVA and Tukey tests (p<0.05). According to the results of the FTIR etching with PA reduced the amount of phosphate and carbonate when compared to PAA. ICTPtp release of PA was significantly higher A than PAA (p > 0,05). CTXtp showed no difference between the PA and PAA (p < 0,05). For UTS there was no difference between PAA and control, but they were significantly higher (p<0.05) than PA. For µTBS in MPa, there is no statistical difference among all the etching protocols tested, as well in both storage periods of analysis (p < 0,05). The most prevalent failure mode were adhesives associated with mixed. SEM analysis highlighted a better quality of AI after 12 months for PA and PAA. However, after 12 months only SE did not show NL. Then, the self-etching protocol seems to be a better choice regarding universal adhesive systems which have functional monomers in their blend(AU)

Micro-computed Tomographic Evaluation of Dentinal Microcrack Formation after Using New Heat-treated Nickel-titanium Systems.

INTRODUCTION: The aim of the present study was to evaluate the frequency of dentinal microcracks observed after root canal preparation with HyFlex CM (Coltène/Whaledent, Altstätten, Switzerland), HyFlex EDM (Coltène/Whaledent), Vortex Blue (Dentsply Tulsa Dental Specialties, Tulsa, OK), and TRUShape (Dentsply Tulsa Dental Specialties) systems using micro-computed tomographic (micro-CT) analysis. METHODS: Forty human mandibular incisors with 1 and straight root canals were randomly assigned to 4 experimental groups (n = 10) and 1 control group for root canal preparation: group 1, HyFlex CM; group 2, HyFlex EDM; group 3, Vortex Blue; and group 4, TRUShape. The specimens were scanned using high-resolution micro-CT imaging before and after root canal preparation. Afterward, preoperative and postoperative cross-sectional images of the teeth were screened to identify the presence of dentinal defects. The number of microcracks was determined as a percentage for each group. RESULTS: Before and after canal preparation, 36,152 cross-sectional images were examined. Four thousand four hundred fifty-two (12.31%) dentinal defects were observed. No new microcracks were observed after root canal instrumentation with the tested systems. CONCLUSIONS: Root canal preparation with the HyFlex CM, HyFlex EDM, Vortex Blue, and TRUShape systems did not induce the formation of new dentinal microcracks on straight root canals of mandibular incisors.

Stress Generation during Pecking Motion of Rotary Nickel-titanium Instruments with Different Pecking Depth.

INTRODUCTION: The aim of this study was to evaluate the effect of different pecking depth on the stress generated by the screw-in forces of a rotating endodontic file in simulated canals. METHODS: Twenty simulated resin blocks with a J-shaped curvature were used. Twenty OneG files (MicroMega, Besançon, France) were assigned for a screw-in test depending on the pecking depth in 2 groups (n = 10). The files were operated at 300 rpm, and the up and down speed was controlled at 1 mm/s stroke velocity and a 10-millisecond dwell time using a customized device. The distances (pecking depth) for the pecking motion were 2 mm or 4 mm for each group; "6 mm forward and 4 mm backward" and "6 mm forward and 2 mm backward" movements were applied, respectively, for the 2 pecking groups. During the operation, the positive and negative apical loads were recorded at a rate of 50 Hz using customized software attached to the device. The maximum negative apical load (screw-in force [SF]) was recorded, and the total energy during pecking motion until the file reached the working length (cumulative screw-in forces [CSFs]) was computed. The data were analyzed using an independent t test at a significance level of 95%. RESULTS: No significant difference in SF was found between the 2 groups of pecking depths. However, the longer pecking depth (4-mm group) showed a significantly larger CSF compared with the shorter pecking depth group (P < .05). CONCLUSIONS: The shorter pecking depth may generate lower overall stresses for the root dentin as well as the instrument.

Fracture Forces of Dentin after Surface Treatment with High Speed Drill Compared to Er:YAG and Er,Cr:YSGG Laser Irradiation.

Dental tooth restorative procedures may weaken the structural integrity of the tooth, with the possibility of leading to fracture. In this study we present findings of coronal dentin strength after different techniques of surface modification. The fracture strength of dentin beams after superficial material removal with a fine diamond bur high speed drill hand piece, Er:YAG (2.94 µm, 8 J/cm(2)), and Er,Cr:YSGG (2.78 µm, 7.8 J/cm(2)) laser irradiation slightly above the ablation threshold was measured by a four-point bending apparatus. Untreated dentin beams served as a control. A total of 58 dentin beams were manufactured from sterilized human extracted molars using the coronal part of the available dentin. Mean values of fracture strength were calculated as 82.0 ± 27.3 MPa for the control group (n = 10), 104.5 ± 26.3 MPa for high speed drill treatment (n = 10), 96.1 ± 28.1 MPa for Er,Cr:YSGG laser irradiation (n = 20), and 89.1 ± 36.3 MPa for Er:YAG laser irradiation (n = 18). Independent Student's t-tests showed no significant difference between each two groups (p > 0.05). Within the parameter settings and the limits of the experimental setup used in this study, both lasers systems as well as the high speed drill do not significantly weaken coronal dentin after surface treatment.

Análise in vitro da morfologia e da resistência de união da resina composta à dentina erodida e irradiada com laser de Er: YAG com largura de pulso super curta / In vitro analysis of morphology and bond strength of composite resin to dentin eroded and irradiated with a super short pulse Er: YAG laser

Lesões dentais por erosão têm sido cada vez mais presentes na prática clínica. A restauração direta com resina composta é uma das opções de tratamento para lesões severas, em que há comprometimento estético/funcional. Com o aprimoramento da tecnologia, a utilização do laser para pré-tratamento da superfície dentinária, antes do condicionamento ácido, tem sido considerada como método alternativo para melhorar a adesão das resinas compostas às superfícies erodidas. Assim, o objetivo deste estudo in vitro foi avaliar a influência da irradiação com laser de Er:YAG (2,94 ?m), de pulso super-curto, na adesão da resina composta à superfície dentinária erodida. Quarenta e seis discos de dentina foram obtidos a partir de 46 dentes terceiros molares humanos. A dentina oclusal planificada de 40 molares humanos teve metade de sua face protegida com fita UPVC (dentina hígida), enquanto na outra metade foi produzida uma lesão de erosão através da ciclagem em ácido cítrico (0,05 M, pH 2,3, 10 minutos, 6x/dia) e solução supersaturada (pH 7,0, 60 minutos entre os ataques ácidos). Metade das amostras foi irradiada com o laser de Er:YAG (50 ?s, 2 Hz, 80 mJ, 12,6 J/cm2) e a outra não (grupo controle). Em cada grupo de tratamento (laser ou controle) (n=10), um sistema adesivo autocondicionante foi utilizado e, então, confeccionados 2 cilindros de resina composta, tanto do lado erodido como no hígido (total de 4 cilindros), os quais foram submetidos à avaliação da Resistência de União através do ensaio de microcisalhamento (1 mm/min), após armazenamento em saliva artificial por 24 h. A análise do padrão de fratura foi realizada em microscópio óptico (40x). Por meio da Microscopia Eletrônica

de Varredura (MEV), a morfologia das superfícies dentinárias hígida e submetida ao desafio erosivo, antes e após o tratamento com laser de Er:YAG (n=3), foi avaliada. Os valores obtidos de resistência de união (MPa) foram submetidos ao teste ANOVA e de comparações múltiplas de Tukey (p<0,05) e as análises das eletromicrografias foram feitas de forma descritiva. A análise morfológica da superfície mostrou alterações significativas na dentina hígida irradiada e na submetida à ciclagem erosiva, irradiada ou não. Quanto à resistência de união, houve diferença entre os 4 substratos analisados, sendo: dentina hígida irradiada (12,77±5,09 A), dentina hígida não irradiada (9,76±3,39 B), dentina erodida irradiada (7,62±3,39 C) e dentina erodida não irradiada (5,12±1,72 D). Houve predominância de padrão de fratura do tipo adesiva. Com base nos resultados e nos parâmetros de irradiação utilizados neste estudo, pode-se concluir que a erosão reduz a adesão em dentina e que o tratamento da superfície dentinária com laser de Er:YAG de largura de pulso super curta aumenta a adesão no substrato erodido ou hígido.

Dental erosion injuries have been increasingly present in clinical practice. Direct restoration with composite resin is one of the treatment options for severe injuries, where there is aesthetic/functional impairment. With the improvement of technology, laser-irradiation for pre-treatment of dentin before surface etching has been considered as an alternative method to improve the adhesion of composite resins to eroded surfaces. The objective of this in vitro study was to evaluate the influence of the irradiation with a super-short pulse Er:YAG (2.94 ?m) laser to the adhesion of composite resin to eroded dentin surface. Forty six dentin discs were obtained from 46 third molars. Forty samples of planned occlusal dentine, obtained from human molars, had half of their surface protected with plastic tape (sound dentin), while the other half was submitted to erosive cycles, consisted on immersion on citric acid (0.05 M, pH 2.3, 10 minutes, 6x/day) and supersaturated solution (pH 7.0, 60 minutes of acid attacks). Half of the samples was irradiated with the Er:YAG laser (50 ?s, 2 Hz, 80 mJ, 12.6 J/cm2) and the other was kept as control. In each treatment group (n = 10), a self-etching adhesive system was used and then two cylinders of composite resin were prepared, on both eroded and sound dentin (total of 4 cylinders). Microshear bond strength test was performed (1 mm/min), after 24 hours storage in artificial saliva.

The analysis of the fracture pattern was determined by optical microscopy (40x). The morphology of sound and eroded dentin, before and after treatment with the Er:YAG laser (n = 3) was evaluated under Scanning Electron Microscopy (SEM). Bond strength values (MPa) were subjected to ANOVA and Tukey multiple comparisons test (p<0.05). The analyses of electron micrographs were made descriptively. Morphological analysis of the surface showed significant changes in irradiated and sound dentin subjected to erosive cycling. As for the bond strength, there were differences among the groups, as follows: sound dentin submitted to irradiation (12.77 ± 5.09 A), non-irradiated sound dentin (9.76 ± 3.39 B), eroded dentin submitted to irradiation (7 62 ± 3.39 C) and non-irradiated eroded dentin (5.12 ± 1.72 D). There was a predominance for the adhesive mode of failure. It was concluded that the erosion reduces the adhesion to dentin and that treating the dentin surface with a super-short-pulse Er:YAG laser increases adhesion to both eroded or sound dentin.

Comparison of dentinal and apical crack formation caused by four different nickel-titanium rotary and reciprocating systems in large and small canals.

This study compared dentinal and apical crack formation after instrumentation with different nickel-titanium systems at two different working lengths (WL) in large and small canals. Two hundred and eighty human teeth were randomly distributed into two control and 12 experimental groups (n=20 each). Large and small canals were instrumented by the WaveOne, Protaper Universal System (PTU), Twisted File (TF), or Twisted File Adaptive (TFA) at 1 mm shorter than canal length (CL-1 mm) or 1 mm beyond apical foreman (CL+1 mm). Horizontal sections were microscopically observed to evaluate the dentinal cracks (only large canals). Scanning electron microscopy images were taken before and after instrumentation to assess apical cracks. All file types caused more apical cracks in small canals than in large canals regardless of the WL. During over-instrumentation (WL=CL+1 mm), the WaveOne and PTU groups developed significantly more dentinal cracks at the 6 and 9 mm sections than the TF and TFA groups.

Classification and Epidemiology of Traumatic Dentoalveolar Injuries in Dogs and Cats: 959 Injuries in 660 Patient Visits (2004-2012).

The objective of this study was to determine the epidemiology of traumatic dentoalveolar injuries (TDI) in dogs and cats and to evaluate the applicability of a human classification system for TDI in dogs and cats. All patients diagnosed with a TDI were identified from the University of Wisconsin-Madison School of Veterinary Medicine Dentistry and Oral Surgery Service case log and the hospital patient processing software. The study population consisted of 621 dogs and cats, in a total of 660 patient visits from 2004 to 2012, admitted for oral treatment and subsequently diagnosed with at least one TDI Medical records including diagnostic imaging studies were reviewed to group the injury according to a classification system used in humans for TDI. Patient signalment, tooth injured, and number of injuries per patient were recorded and tabulated. The overall prevalence of TDI was 26.2%. The mean +/- SD number of TDI per patient was 1.45 +/- 0.85. All 14 classes of TDI recognized by the classification system utilized in humans were identified, and all (100%) TDI identified in this study were classifiable using this system. Enamel-dentin-pulp fracture was the most common TDI (49.6%). The most commonly injured teeth were the mandibular or maxillary canine teeth (35.5%). The most common age for dogs and cats with TDI were 3-6 years (33.0%) and 7-10 years (31.3%). With a frequency of 1 in 4 animals, TDI are common and represent a significant pet health concern. Most TDI are considered severe and require timely, and sometimes immediate, treatment. The adoption and utilization of a complete classification system, such as the one used in this study, is recommended in order to improve future epidemiological study of TDI in animals.

Synchrotron light-based µCT to analyse the presence of dentinal microcracks post-rotary and reciprocating NiTi instrumentation.

OBJECTIVES: The purpose of this study was to determine in vitro using a synchrotron radiation-based µCT (SRCT) whether rotary and reciprocating nickel titanium (NiTi) instrumentations lead to the formation of dentine microcracks. MATERIAL AND METHODS: Fourteen extracted human molars were obtained with ethical approval. Seven distobuccal roots of the maxillary molars and seven mesial roots of the mandibular molars were assigned to two experimental groups: (A) prepared with rotary Pro Taper instrumentation (n = 6) and (B) reciprocating WaveOne (n = 6). Irrigation with 1 % NaOCl and 17 % EDTA solutions was carried out. The remaining roots served as positive control with induced fractures (group C). SRCT was used to scan all samples pre and post-operatively. An imaging software was used to determine the number and length of microcracks. Statistical analyses weighed differences between pre and post-instrumentation and between shaping methods. RESULTS: A significant increase in the number and length of microcracks was detected post-shaping. No significant difference between rotary and reciprocating instrumentation was observed. CONCLUSIONS: Within the limitations of this in vitro study, an increased number and length of microcracks was induced by mechanical instrumentation. Reciprocating and rotary instrumentation are similar in terms of effect. CLINICAL SIGNIFICANCE: Dentinal damage may occur following rotary and reciprocating instrumentation.

Anti-dentine Salivary SIgA in young adults with a history of dental trauma in deciduous teeth

Anti-dentin autoantibodies are associated with inflammatory root resorption in permanent teeth and are modulated by dental trauma and orthodontic force. However, it is not known whether deciduous tooth trauma can stimulate the development of a humoral immune response against dentin. The aim of this study was to evaluate the levels of salivary SIgA reactivity against human dentin extract in young adults with a history of trauma in the primary dentition. A sample of 78 patients, aged 18 to 25, who had completed an early childhood (0 to 5 years old) caries prevention program years earlier at the Universidade Estadual de LondrinaPediatric Clinic, underwent radiographic examination and salivary sampling. Anti-dentin SIgA levels were analyzed by immunoenzymatic assay and Western blotting. Although dental trauma to deciduous teeth had occurred in 34 (43.6%) of the patients, no differences in SIgA levels were detected between individuals who had experienced trauma and those who had not (p > 0.05). Multivariate regression analysis showed no association between dental trauma and SIgA levels (p > 0.05). Patients with a history of deciduous trauma presented low levels of anti-dentin antibodies, associated with orthodontic root resorption (p < 0.05). Western blot analysis showed that salivary antibodies recognized a single band of approximately 45 kDa in dentin extract. We concluded that salivary SIgA recognizes a specific component of the dentin matrix and that anti-dentin antibodies were not triggered by trauma to primary teeth. However, trauma to deciduous teeth may down-modulate SIgA in response to orthodontic root response.

The clinical meaning of external cervical resorption in maxillary canine: transoperative dental trauma

External Cervical Resorption in maxillary canines with pulp vitality is frequently associated with dental trauma resulting from surgical procedures carried out to prepare the teeth for further orthodontic traction. Preparation procedures might surgically manipulate the cementoenamel junction or cause luxation of teeth due to applying excessive force or movement tests beyond the tolerance limits of periodontal ligament and cervical tissue structures. Dentin exposure at the cementoenamel junction triggers External Cervical Resorption as a result of inflammation followed by antigen recognition of dentin proteins. External Cervical Resorption is painless, does not induce pulpitis and develops slowly. The lesion is generally associated with and covered by gingival soft tissues which disguise normal clinical aspects, thereby leading to late diagnosis when the process is near pulp threshold. Endodontic treatment is recommended only if surgical procedures are rendered necessary in the pulp space; otherwise, External Cervical Resorption should be treated by conservative means: protecting the dental pulp and restoring function and esthetics of teeth whose pulp will remain in normal conditions. Unfortunately, there is a lack of well-grounded research evincing how often External Cervical Resorption associated with canines subjected to orthodontic traction occurs.

A reabsorção cervical externa em caninos superiores com vitalidade pulpar em sua quase totalidade está associada a traumatismo dentário decorrente de procedimentos cirúrgicos associado à preparação desse dente para ser tracionado ortodonticamente. Nessa preparação pode se manipular cirurgicamente a junção amelocementária ou luxar o dente com forças excessivas ou com testes de movimentação além dos limites de tolerância estrutural do ligamento periodontal e tecidos cervicais. A exposição dentinária na junção amelocementária é o estopim para se iniciar uma reabsorção cervical externa a partir de uma inflamação induzida na região seguida de reconhecimento antigênico das proteínas dentinárias. A reabsorção cervical externa é indolor, não induz pulpites e tem uma evolução lenta. Em geral, a lesão está associada e recoberta por tecidos moles gengivais que mantêm, por longos períodos, os aspectos clínicos normais, induzindo diagnósticos tardios, quando o processo se aproxima dos limites pulpares. O tratamento endodôntico está indicado apenas em função de procedimentos operatórios que se fazem necessários no espaço pulpar; caso contrário, a reabsorção cervical externa deve ser tratada de forma conservadora, protegendo a polpa dentária e restaurando a função e estética do dente que permanecerá com sua polpa normal. Infelizmente, não sabemos, com base em pesquisas de casuísticas bem estabelecidas, qual é a frequência da reabsorção cervical externa associada a caninos ortodonticamente tracionados.