The effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis: A retrospective study.

PURPOSE: The objective of this retrospective study was to evaluate the effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri-implantitis. MATERIAL AND METHODS: Records of 96 patients and 148 external hexagon (EH) implants with time in function ranging from 1 to 17 years were included in the study. The most recent clinical and radiographic data were collected from records and the prevalence of peri-implantitis was defined according to the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions. Marginal bone level (MBL), emergence angle (EA), emergence profile (EP), and crown/implant platform horizontal ratio (CIHR) were obtained from periapical radiographs. Dichotomous variables at the patient- and implant level were compared with association tests. Mann-Whitney U-Test was performed to compare continuous quantitative values between the studied groups. Binomial logistic regression was conducted to identify risk indicators associated with the peri-implantitis event at the patient- and implant level, with the significance level set at 5% for all tests. RESULTS: Nineteen patients (19.2%) and 24 implants (16.2%) with a mean time in function of 5.0 ± 4.7 years were classified as having peri-implantitis. No statistically significant differences concerning gender, mean age, implant location in the jaw, or time in function were observed between patients with or without peri-implantitis (p > 0.05). Of 24 implants with peri-implantitis 10 (41.7%) displayed EA ≤ 30° (16.4%) while 14 (58.3%) presented EA > 30° with no statistical difference between the groups (p > 0.05). No statistically significant associations were identified between EA, EP, or CIHR and the prevalence of peri-implantitis. CONCLUSION: The findings seem to indicate that the EA, EP, and CIHR of single restorations over external hexagon implants are not associated with the presence of peri-implantitis. However, prospective studies with larger samples are required to better ascertain such an association in the long term.

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.

Effects of 50- and 70-Gy radiation doses on polymethyl methacrylate denture bases.

The aim of this study was to evaluate the flexural strength and Knoop microhardness of the polymethyl methacrylate (PMMA) used in dental prostheses after receiving therapeutic radiation doses of 50 and 70 Gy. Thirty-six acrylic resin plates measuring 65.0 × 10.0 × 3.3 mm were fabricated and polymerized using a microwave. The specimens were randomly divided into 3 groups (n = 12): group 1, which received no radiation; group 2, which received 1 fractioned dose of 2 Gy per day, 5 days per week, for 5 weeks, totaling 50 Gy; and group 3, which received 1 fractioned dose of 2 Gy per day, 5 days per week, for 7 weeks, totaling 70 Gy. All specimens remained in ballistic gel at a temperature of 37°C throughout the study. Afterward, the specimens underwent flexural strength and Knoop microhardness tests. All data were analyzed using analysis of variance and Tukey post hoc test (P < 0.05). For flexural strength, there was a statistically significant difference between groups 1 and 2 (P = 0.012) and between groups 1 and 3 (P = 0.048). For Knoop microhardness, there was a difference between groups 1 and 2 (P = 0.001) and between groups 1 and 3 (P = 0.006). For both flexural strength and microhardness, groups 2 and 3 showed greater values than group 1. Therapeutic radiation doses of 50 and 70 Gy increased the flexural strength and Knoop microhardness of PMMA used in dental prostheses.

Evaluation of biofilm accumulation on and deactivation force of orthodontic Ni-Ti archwires before and after exposure to an oral medium: A prospective clinical study.

Background. This in vitro study aimed to evaluate biofilm accumulation on and deactivation force of orthodontic nickeltitanium (NiTi) archwires before and after exposure to an oral medium. Methods. Four commercial brands of orthodontic NiTi 0.016" archwires were examined before and after exposure to the oral medium for 4 weeks. Six archwire segments, 30 mm in length, from each manufacturer were tested in a device with four selfligating brackets, channel 0.022", adapted to a universal test machine to evaluate the deactivation force between 0.5 and 3 mm of deflection. The presence of biofilm on the archwire surfaces was evaluated by scanning electron microscopy, before and after exposure to the oral medium. The Wilcoxon and kappa tests were applied to the biofilm scores, three-way ANOVA for repeated measures (Bonferroni post-test), and linear regression between biofilm and deactivation force. Results. The exposure to the oral medium promoted moderate to severe presence of debris on the archwire surfaces and caused a reduction in deactivation force for the Ormco and GAC brands, while maintaining them with adequate force levels. The MORELLI and ORTHOMETRIC archwires underwent no significant reduction in deactivation force; moreover, these maintained elevated levels of force after exposure to the oral medium. The Spearman test indicated a low correlation between biofilm accumulation and deflection force for the Morelli (R2=0.132 and P=0.683) and Orthometric (R2=0.308 and P=0.330) brands. On the other hand, the GAC (R=0.767 and P=0.004) and ORMCO (R=0.725 and P=0.008) brands exhibited statistically significant correlation between these variables. Conclusion. Exposure to the oral medium for one month might give rise to significant changes in the dissipation of forces of orthodontic NiTi archwires, resulting from biofilm accumulation.

Effect of radiotherapy on the artificial acrylic resin tooth bond to the acrylic resin denture base.

This study aimed to evaluate the fracture resistance of the bond between an artificial acrylic resin tooth and its acrylic resin denture base after radiotherapy with maximum therapeutic doses of 40 and 70 Gy. Sixty wax blocks were fabricated with heights of 4.0 cm and bases with dimensions of 1.0 cm2 and 1.8 cm2. A posterior acrylic resin tooth was placed on each wax block on the base with the smallest area. Thirty of the blocks were thermopolymerized using the conventional technique and 30 using the microwave technique, and the blocks were divided into 6 groups (n = 10): 1 (control, conventional) and 2 (control, microwave) did not receive radiation; 3 (conventional) and 4 (microwave) received a total dose of 40-Gy radiation; and 5 (conventional) and 6 (microwave) received a total dose of 70 Gy. The groups of 40 and 70 Gy received fractional doses of 2 Gy per day, 5 days per week, until their respective total dose was completed. During the study, all specimens were stored in ballistic gel at a temperature of 37ºC. After the radiotherapy treatments, the bonds between teeth and bases in all groups were submitted to a fracture resistance test. Analysis of variance and Tukey test (P < 0.05) verified no statistically significant differences between groups 1 and 3 (P = 0.727), 2 and 4 (P = 0.537), or 4 and 6 (P = 0.727). However, there were statistically significant differences between groups 3 and 5 (P < 0.001), 5 and 1 (P = 0.006), and 6 and 2 (P = 0.034). Therefore, for both polymerization techniques, the maximum radiation dose of 70 Gy weakened the bond between the acrylic resin tooth and its acrylic resin base.

Rehabilitación bucal después de la retirada de un fibroma cemento-osificante central / Oral rehabilitation after removal of a central cemento-ossifying fibroma

ABSTRACT Introduction: The cemento-ossifying fibroma is a benign bone neoplasm that affects mainly the female sex during the third or fourth decades of life. This lesion has a slow growth and the treatment is the surgical removal of the tumor, because radiotherapy is not indicated. Objective: to describe and discuss a case of central cemento-ossifying fibroma. Case report: A 41-year-old female patient sought dental treatment due to tooth mobility in the anterior region of the mandible. In this region of the mandible, an increase in volume was noted with a firm consistency on palpation, covered by normal mucosa, and displacement of teeth. Radiographically, the presence of an extensive lesion in this region was observed. An incisional biopsy was performed which led to the final diagnosis of central cemento-ossifying fibroma. Subsequently the tumor was completely removed. An autogenous bone graft was performed and four osseointegrated implants were installed to rehabilitate the patient. Implant-supported prostheses (lower arch) and a complete denture (upper arch) were installed to restore esthetics and function of the patient's oral cavity. Conclusion: Despite being a benign tumor, the central cemento-ossifying fibroma caused functional and aesthetic damage to the patient and required a complex rehabilitation treatment. After approximately 5 years of tumor removal, there was no recurrence of the lesion or signs of peri-implant or periodontal diseases, evidencing the success of the treatments(AU)

RESUMEN Introducción: El fibroma cemento-osificante es una neoplasia ósea benigna que afecta principalmente al sexo femenino durante la tercera o cuarta décadas de la vida. Esta lesión tiene un crecimiento lento y el tratamiento es la extirpación quirúrgica del tumor, porque la radioterapia no está indicada. Objetivo: Describir y analizar un caso de un fibroma cemento-osificante central. Presentación caso: Paciente de 41 años de edad buscó tratamiento dental debido a la movilidad dental en la región anterior de la mandíbula. En esta región de la mandíbula se observó un aumento de volumen con una consistencia firme a la palpación, cubierta por la mucosa normal y desplazamiento de los dientes. Radiográficamente, se observó la presencia de una lesión extensa en esta región. Se realizó una biopsia incisional, que indicó el diagnóstico final del fibroma cemento-osificante central. Después el tumor fue completamente extirpado. Se realizó un injerto óseo autógeno y, posteriormente, se instalaron cuatro implantes osteointegrados para rehabilitar al paciente. Se instalaron prótesis soportadas por implantes (arco inferior) y una dentadura (arco superior) para restablecer la estética y la función de la cavidad bucal de la paciente. Conclusiones: A pesar de ser un tumor benigno, el fibroma cemento-osificante central causó daños funcionales y estéticos al paciente y requirió un complejo tratamiento de rehabilitación. Después de 5 años de la extirpación del tumor, no hubo recurrencia de la lesión. Además, no hubo signos de enfermedades periimplantarias y/o periodontales, lo que demuestra el éxito del tratamiento(AU)

Recuperando o guia incisal de um paciente com bruxismo: Relato de caso / Recovering the incisal guidance of a patient with bruxism: Case report

O objetivo do presente relato de caso clínico foi descrever a reabilitação estética e funcional dos incisivos anteriores superiores de um paciente com bruxismo. Paciente do gênero masculino, 23 anos de idade, bruxoma, procurou tratamento para os dentes anteriores superiores devido aos diastemas dentários e também por causa dos comprimentos reduzidos dos incisivos centrais superiores. Para isso, foi realizada a gengivoplastia e osteotomia na região dos incisivos centrais superiores com o objetivo de melhorar as posições dos contornos gengivais e aumentar o comprimento desses dentes. Após 90 dias, o clareamento dentário foi realizado. Depois de 1 mês as facetas de resina composta foram confeccionadas nos incisivos centrais superiores. Durante o tratamento as necessidades e perspectivas do paciente foram levadas em consideração para alcançar o sucesso clínico. Após a conclusão dos procedimentos, o resultado final foi satisfatório. Portanto, um plano de tratamento integrado se mostrou de extrema valia, principalmente quando o paciente é devidamente esclarecido das opções disponíveis de tratamento e colabora com o mesmo.

The objective of the present case report was to describe the aesthetic and functional rehabilitation of the upper anterior incisors of a patient with bruxism. A 23-year-old male patient, with bruxism, sought treatment for his upper anterior teeth due to diastemas and reduced lengths of the upper central incisors. The gingivoplasty and osteotomy were performed in the region of the upper central incisors to improve the positions of the gingival contours and increase the length of these teeth. After 90 days, teeth whitening was performed. After 1 month the composite resin veneers were made in the upper central incisors. During treatment, the needs and perspectives of the patient were considered to achieve clinical success. The treatments were finalized, and the final result was satisfactory. Therefore, an integrated treatment plan proved to be extremely important, especially when the patient is adequately informed of the available treatment options and collaborates with the treatment.

Effect of using the New Glass Fiber Pin in Resin Composite Restorations.

AIM: The purpose was to compare the fracture strength between restorations containing the metal pin (MP) and those containing the glass fiber pin (GFP). MATERIALS AND METHODS: Forty-five healthy bovine anterior teeth were used in this study. A preparation of 4 mm × 4 mm was created on the incisal surface of each tooth. All teeth were prepared in the same way. The teeth were randomly divided into three groups (n = 15): group I-control: teeth restored with resin composite (RC) only, without reinforcement; group II-Each tooth was restored with a MP and RC; group III-Each tooth was restored with a GFP and RC. The specimens were left in an oven at a temperature of 37°C for 24 hours before performing the fracture strength tests. The fracture strength test was performed in a universal test machine at an angle of 90°. RESULTS: The Tukey test (p ≤ 0.05) showed that for the variable maximum force (kgf), there was no statistically significant difference among the groups (p = 0.272). The chi-square test showed that groups II and III presented over 70% of cohesive-adhesive type fractures when compared with group I (over 70% of adhesive fractures), and this difference was statistically significant (p < 0.05). CONCLUSION: The pins tested did not increase the fracture resistance of the restorations (RC) in comparison with group I (without reinforcement); however, with the use of the MP and GFP, there was a predominance of cohesive-adhesive fractures (groups II and III). CLINICAL SIGNIFICANCE: Evaluate if the new GFP can generate greater resistance to fracture of RC restorations.

Comparison between aluminum chloride and tetryzoline hydrochloride for control of vertical gingival displacement and crevicular fluid / Comparação entre cloreto de alumínio e o cloridrato de tetrizolina no controle do afastamento gengival vertical e fluído crevicular

Introduction: The use of a gingival displacement cord with a gingival displacement substance is a common procedure for taking a quality impression of the cervical terminal in teeth for prosthetic purposes. Objective: To evaluate whether the mechanical-chemical method with 0.05% tetryzoline hydrochloride or 25% aluminum chloride is capable of reducing crevicular fluid, and displacing a statistically significant larger quantity of gingival tissue vertically, compared with the mechanical method (without chemical substances). Material and method: Ten patients were selected, and then No. 000 and 1 Ultrapak cords were randomly positioned on teeth 13, 21 and 23. Group I - cord with no chemical substance; Group II - cords impregnated with tetryzoline hydrochloride and Group III - cords impregnated with aluminum chloride. Using dental stone models, thirty images were captured with a camera coupled to a loupe to analyze the degree of gingival displacement. Crevicular fluid was quantified using a high-precision scale and individualized strips of absorbent paper for each tooth on which gingival displacement was performed. Result: There was no statistical difference between the three groups relative to the amount of vertical gingival displacement (Anova, p=0.26). As regards reduction in crevicular fluid, there was no difference between the test and control groups (Wilcoxon and Friedman, p < 0.05). Conclusion: The use of tetryzoline hydrochloride or aluminum chloride to impregnate the gingival displacement cord did not improve the quantity of vertical gingival displacement and did not reduce the amount of crevicular fluid.

Introdução: A utilização de fio de afastamento gengival com uma substância de afastamento gengival é um procedimento comum para se realizar uma moldagem com qualidade do término cervical em dentes com finalidade protética. Objetivo: Avaliar se o método mecânico-químico com cloridrato de tetrizolina a 0,05% ou cloreto de alumínio a 25% são capazes de reduzir o fluido crevicular e afastar o tecido gengival verticalmente em uma quantidade maior, estatisticamente significante, em comparação com o método mecânico de afastamento (sem substâncias químicas). Material e método: Dez pacientes foram selecionados, e os fios Ultrapak n° 000 e 1 foram posicionamos de maneira randomizada nos dentes 13, 21 e 23. Grupo I: fio sem substância química; Grupo II: fio impregnado com cloridrato de tetrizolina; Grupo III: fio impregnado com cloreto de alumínio. Utilizando modelos de gesso, foram capturadas trinta imagens com uma câmera acoplada a uma lupa, para análise do grau de afastamento. O fluxo crevicular foi quantificado através de uma balança de alta precisão, a partir de tiras de papel absorvente personalizadas para cada dente que recebeu afastamento gengival. Resultado: Não houve diferença estatística entre os três grupos quanto a quantidade de afastamento gengival vertical (Anova, p=0,26). Quanto a redução de fluido crevicular, não houve diferença entre os grupos teste e controle (Wilcoxon e Friedman, p < 0,05). Conclusão: A utilização do cloridrato de tetrizolina ou cloreto de alumínio em fio de afastamento gengival não melhorou a quantidade de afastamento vertical da gengiva e não reduziu a quantidade de fluido crevicular.

Planejamento Interdisciplinar para reabilitação oral: um relato de caso de protocolo Bränemark / Interdisciplinary Planning for the Oral Rehabilitation: Branemark´S Clinic Case Report

A reabilitação oral em pacientes edêntulos é um desafio que a odontologia atual vem tentando superar com implantes osseointregrados. O fator socioeconômico ainda é uma das causas de maior dificuldade para o tratamento em pacientes edêntulos. No presente relato de caso, será descrita a associação entre projeto de extensão e atendimentos interdisciplinares odontológicos para a reabilitação de um paciente com baixa condição financeira. Este trabalho relata o caso de um paciente de 55 anos que se queixava de sensibilidade em alguns dentes, desconforto com a prótese removível inferior, dificuldades mastigatórias, fonéticas, assim como, estética insatisfatória. Com o objetivo de restabelecer função e estética para uma melhor qualidade de vida do paciente, um tratamento envolvendo várias áreas da odontologia foi realizado. Após avaliação de uma equipe interdisciplinar e posterior discussão com o paciente sobre os possíveis planos de tratamento, realizou-se a exodontia dos dentes inferiores e instalação de cinco implantes. Para reabilitação protética, realizou-se a confecção do protocolo Bränemark na arcada inferior, que apresentava pouco rebordo ósseo e de uma nova prótese total superior. Ao final foi evidente a melhora estética e funcional obtida com o tratamento, tendo o paciente recuperado a autoestima e a vontade de cuidar de sua saúde bucal. A partir desse relato de caso pode-se observar que o protoloco Bränemark é uma indicação viável no tratamento de pacientes edêntulos e com pouco rebordo alveolar por conferir estabilidade à prótese.(AU)

Oral rehabilitation in edentulous patients is a challenge that the current dentistry has been trying to overcome through osseointegrated implants. The socio-economic factor is still a cause of the greatest difficulty for treatment in edentulous patients. In this case report we describe the association between extension project and interdisciplinary care for the rehabilitation of a patient with low financial condition. This study reports the case of a 55 year-old patient who complained about sensitivity in some teeth, discomfort with mandibular removable partial denture, masticatory and phonetic difficulties, as well as poor aesthetics. The purpose of restoring function and aesthetics for a better life quality of the patient, a treatment involving various dental specialties was conducted. After the evaluation of a interdisciplinary team and further discussion with the patient about possible treatment plans, it was decided to extract the mandibular teeth and placement of five dental implants. For the prosthetic rehabilitation Bränemark protocol was made on the mandibular region which had little bony ridge, and a new maxillary removable complete denture. In the end of the treatment there was evident aesthetic and functional improvement and the patient regained self-esteem and the will to care of his oral health. Based on this case report it can be noted that Branemark protocol is a viable choice for the treatment of edentulous patients and it is indicated in cases that there is little alveolar ridge to confer prosthesis stability.(AU)

Prosthetic rehabilitation using association of total and implant-supported total denture (Brånemark protocol) - case report

Introduction: The rehabilitation with implant-supported fixed prosthesis is an effective therapy for the treatment of edentulous patients, especially for mandibles, following Brånemark protocol. Case report:A male patient, aged 62 years, fully edentulous, already had 05 implants, between mental foramen. The rehabilitative therapy employed used both maxillary total denture upper associated with mandibular implant-supported denture following Brånemark protocol. Conclusion: The implant-supported denture following Brånemark protocol is a viable alternative, providing stability to the denture, masticatory efficiency, and aesthetics. Each case should be carefully analyzed and planned to reach a successful treatment.

Influence of educational materials on the hygiene and utilization habits of denture wearers.

The objective of this study was to investigate the influence of educational materials on the denture hygiene and utilization habits of 70 adult volunteers who had been using complete dentures for at least 5 years. On the day they received new dentures, 32 patients were provided with an illustrated leaflet and verbal instructions on oral hygiene and utilization habits, while the remaining 38 participants were advised to continue cleaning and wearing their new dentures as they had their previous dentures. After a 6- to 10-week period, 66 of 70 subjects were interviewed about socioeconomic factors, denture hygiene, and utilization habits. The percentage of patients with a proper denture care routine was low in both groups, suggesting that patients had a tendency not to change old habits. However, statistical analysis showed a positive correlation between receiving instruction and performing denture care in a way that is closer to the recommended method: brushing without toothpaste, using a specific brush; soaking in a sodium hypochlorite solution; and removing the prosthesis at night. Within the limitations of this study, it was concluded that this approach to patient education could be applied to improve the hygiene and utilization habits of denture wearers as well as encourage the correct use of complete dentures.

Effects of hygiene guidance associated or not to provision of hygiene devices on habits of denture wearers / Influência da orientação associada ou não à distribuição de dispositivos de higiene nos hábitos de portadores de próteses totais

Appropriate hygiene of dentures contributes to the maintenance of oral and systemic health. However, most of denture wearers had never been instructed on how to perform daily oral/denture care. The purpose of this study is to investigate the influence of a guidance material associated or not to the provision of hygiene devices and its effect on the habits of denture wearers. Forty- eight complete denture wearers were randomly divided into three groups. Group N received no guidance on how to clean and wear their dentures, group G received an illustrated leaflet and verbal complementary instructions and group GK received the same guidance as group G and a hygiene kit for denture cleaning. After a six to ten week period they responded to a 'hygiene and wearing habits' questionnaire. Chi-square test was used for statistical analysis considering p < 0.05. Brushing was the most frequent cleaning method, the majority of groups N and G used toothpaste. Participants of group G and GK presented low percentages of individuals with hygiene and wearing routine considered improper. The differences between groups in hygiene and wearing routine were statistically significant (p < 0.001). The proposed guidance material yielded better results when associated to provision of hygiene devices for denture cleaning.

O objetivo deste estudo é investigar a influência de um material de orientação de higiene, associado ou não à distribuição de dispositivos de higiene, nos hábitos de portadores de próteses totais. Quarenta e oito voluntários foram divididos em três grupos. O grupo N não recebeu orientação sobre higienização de próteses. O grupo G recebeu um folheto ilustrado e orientações verbais. O grupo GK recebeu orientações similares as do grupo G e um conjunto de dispositivos para higiene de próteses. Após seis a dez semanas, os voluntários responderam um questionário sobre hábitos de higiene e uso das próteses. A análise estatística foi realizada através do teste qui- quadrado, considerando p < 0.05. A escovação foi o método de higienização mais utilizado, e a maioria dos voluntários dos grupos N e G utilizaram creme dental. Um baixo percentual de participantes do grupo G e GK apresentaram uma rotina de higienização e uso considerada imprópria. Houve diferença estatisticamente significante entre os grupos para a rotina de higienização e uso (p < 0,001). O material de orientação de higiene proposto neste estudo apresentou melhores resultados quando associado à distribuição de dispositivos de higiene.

Reabilitação estética em elemento posterior: endocrown / Aesthetics rehabilitation in a posterior element: endocrown

A reabilitação estética, funcional e duradoura de elementos posteriores é um desafio do cotidiano clinico. As endocrowns são uma alternativa eficaz e de validação cientifica ao clássico uso de retentores intrarradiculares. O presente trabalho objetiva a exposição de um caso clinico no qual foi realizado a confecção de uma coroa endocrown, bem como a discussão a respeito do planejamento do caso e etapas técnicas referentes a essa modalidade de reabilitação

The aesthetic, functional and lasting rehabilitation of posterior elements is a challenge of the clinical routine. The endocrowns are an effective and scientifically validated alternative to the classic use of intracanal retainers. This work aims exposure of a clinical case in which it was carried out construction of a endocrown crown, and the discussion of case planning and technical steps regarding this type of rehabilitation

Avaliação da estabilidade de implantes curtos Neodent, tipo Cone Morse, por meio do teste do torque reverso: estudo preliminar em coelhos / Assessing stability of Neodent Morse taper implants through reverse torque technique testing: a preliminary study in rabbits

Introdução: atualmente, vários tipos de implantes estão disponíveis no mercado. Entre esses, pode-se citar os com conexão do tipo hexágono externo, hexágono interno e Cone Morse,sendo que os com Cone Morse fornecem melhor distribuição e transmissão da força ao longo do implante. O grau de osseointegração de um implante pode ser medido e avaliado por meio do valordo torque reverso. Objetivo: com base nisso, o objetivo do presente trabalho é testar, em implantes do tipo Cone Morse, instalados em tíbias de coelhos, a viabilidade de um novo método de avaliação de torque reverso. Métodos: foram instalados implantes (Neodent Cone Morse WS) em tíbias de coelho. Os animais foram eutanasiados em diferentes períodos de tempo. Os blocos ósseos contendo os implantes foram recortados e o montador correspondente ao implante Cone Morse foi acoplado a esse, formando um pilar único e contínuo. O torque reverso foi simulado utilizando a máquina universal de ensaios EMIC DL 1000. Uma força de compressão foi aplicada sobre o braçoda alavanca (Neodent), acoplado ao dispositivo de montagem do implante. Resultados: os valores obtidos com o teste foram os seguintes: Coelho 1 (imediato) = 1,8Kgf, Coelho 2 (7 dias) = 7,6Kgf, Coelho 3 (15 dias) = 17Kgf, Coelho 4 (30 dias) = 27Kgf, Coelho 5 (45 dias) = 36Kgf. Conclusão: os resultados mostraram-se promissores, uma vez que se obteve um aumento do valor do torque reverso com o passar do tempo.

Introduction: Several types of implants are available on the market, including internal or external hexagonal connections and the Morse Taper connection. The latter provides betterdistribution and transmission of forces throughout the implant. Implant osseointegration can be measured and assessed by reverse torque. Objective: The objective of this study is to test, inMorse Taper implants installed in rabbits’ tibia, the feasibility of a new reverse torque assessment method. Methods: Neodent Morse Taper WS implants were installed in rabbits’ tibia. The animals were sacrificed at different periods of time. The bone blocks containing the implants were cut, anda corresponding mounting device was attached to the implant, forming a single pillar. Reverse torque was simulated using a universal testing machine EMIC DL 1000. Compressive force wasapplied to the arm of the ratchet. Results: The values obtained with the test were: Rabbit 1 (immediate)= 1.8 Kgf, Rabbit 2 (7 days) = 7.6 Kgf, Rabbit 3 (15 days) = 17 Kgf, Rabbit 4 (30 days)=27Kgf, and Rabbit 5 (45 days) = 36 Kgf. Conclusion: Results were promising as they indicated an increase in the value of reverse torque over time.

Comparison of periapical radiography with cone beam computed tomography in the diagnosis of vertical root fractures in teeth with metallic post.

AIM: To compare the diagnostic accuracy of conventional periapical radiography and cone beam computed tomography (CBCT) in detecting vertical root fracture (VRF) in tooth with metallic post (MP). MATERIALS AND METHODS: Twenty endodontically-treated teeth received MPs, artificial fractures were created in 10 teeth, and they were all examined with tomography and radiography. The sample consisted of periapical radiography with post and without post, and tomography with post and without post; each group with five fractured and five non-fractured teeth. The images were evaluated by three dental/maxillofacial radiologists and statistical validations were carried out using receiver operating characteristic (ROC) analysis. RESULTS: Sensitivity and specificity of the area under the ROC (Az) of tomography with post (Az = 0.953) and without post (Az = 0.956) were significantly higher than those of periapical radiography with post (Az = 0.753) and without post (Az = 0.778). CONCLUSION: CBCT was more accurate than conventional periapical radiography in detecting VRF.

Histologic and histomorphometric study of bone repair around short dental implants inserted in rabbit tibia, associated with tricalcium phosphate graft bone / Estudo histológico e histomorfométrico do reparo ósseo ao redor de implantes dentários curtos instalados em tíbias de coelhos associado ao uso do enxerto de fosfato tricálcio

The use of short dental implants represents one way to overcome this limitation, in association with bone grafting procedures. Tricalcium phosphate-based grafts are among those widely used. The purpose of this study was to assess the biocompatibility of this biomaterial in the coverage of bone defects around short dental implants. Ten New Zealand rabbits were used in this study, each animal received 4 implants, two were placed in the right tibia region (control group) and two in the left tíbia region (test group). Forty implants were used, with 4mm diameter and 6mm length. For the control group, holes 6 mm deep were made, and the implants were then inserted at the level of bone tissue. In the control group, the implants of 6 mm in length were inserted to its full length, while in the test group, the same implant was inserted up to 4 mm and left exposed 2 mm. These 2 mm exposed were coated with a bone substitute of tricalcium phosphate and a collagen membrane. After three months, the animals were prepared for histomorphometric analysis, which showed that the control group had a higher number of osteoblasts per µm2 than the test group (p < 0.001). It was concluded that under these experimental conditions, tricalcium phosphate showed tissue biocompatibility and osteoconductive potential.

Para a instalação de implantes em pacientes que possuem perdas ósseas, surgiram os implantes curtos e enxertos ósseos como uma opção de tratamento. Um enxerto que vem sendo utilizado é o biomaterial à base de fosfato tricálcio. O objetivo deste trabalho foi avaliar microscopicamente a neoformação óssea ao redor de implantes curtos. Para este estudo foram necessários dez coelhos da raça Nova Zelândia, sendo que cada animal recebeu quatro implantes, instalados dois na região da tíbia direita (controle) e dois na esquerda (teste). Foram utilizados 40 implantes com diâmetro de 4 mm e comprimento de 6 mm. No grupo controle, implantes de 6 mm foram inseridos no seu comprimento total, enquanto no grupo teste, o mesmo implante de 6 mm foi inserido apenas 4 mm, deixando expostos 2 mm. Esses 2 mm expostos foram cobertos com o enxerto de fosfato tricálcio e uma membrana de colágeno. Após três meses, os animais foram sacrificados para realizar os testes de resistência e a análise histomorfométrica. Na análise histomorfométrica, o grupo controle apresentou maior número de osteoblastos por µm2 do que o grupo teste (p-valor < 0,001). Concluímos que enxertos à base de fosfato tricálcio possuem biocompatibilidade tecidual e potencial osteocondutivo na neoformação óssea ao redor dos implantes.

Endocrown: avaliação da resistência dos cimentos dentários / Endocrown: assessment of resistance of dental cements

O sistema endocrown está sendo cada vez mais usado para restaurações de dentes posteriores com coroas amplamente destruídas e visa uma máxima preservação de estruturas dentais remanescentes. O tipo de cimentação usado nesses casos é fundamental para o sucesso clínico, já que o cimento é usado para selar a interface dente/restauração unindo-os por algum tipo de interação, seja ela mecânica e/ou química. O objetivo dessa pesquisa foi avaliar qual cimento é mais resistente quando submetidos ao teste de tração. Foram analisados três tipos de cimentos: Fosfato de zinco, ionômero de vidro e resinoso dual. Os testes foram realizados em próteses confeccionadas em resina acrílica e cimentadas em dentes bovinos previamente preparados de forma padronizada. Quando submetidos ao teste de ANOVA, o cimento resinoso dual e o fosfato de zinco apresentaram as maiores médias. Esta proximidade de resultados estimula maiores estudos com a cimentação de Endocrown com cimento convencional

The Endocrown system is being increasingly used for posterior restorations with crowns widely destroyed and aims for maximum preservation of remaining tooth structure. The type of cement used in these cases is crucial for clinical success, since the cement is used to seal the interface tooth/restoration joining them for some kind of interaction, whether mechanical and/or chemical. The purpose of this study was to evaluate which cement is more resistant when submitted to tensile test. Were analyzed three types of cements: zinc phosphate, glass ionomer, and resinous dual. The tests were performed in prostheses made of indirect composite resin and cemented in bovine teeth previously prepared in a standardized manner. When submitted to ANOVA test, the dual resin cement and zinc phosphate presented the highest means. This closeness results encourages further studies with cementation Endocrown with conventional cement

Effect of mechanical loading on the removal torque of different types of tapered connection abutments for dental implants.

STATEMENT OF PROBLEM: The mechanical behavior of internal taper implant abutment designs needs to be evaluated. PURPOSE: The purpose of this study was to evaluate the effect of simulated mechanical loading on the removal torque of 1-piece and 2-piece abutments connected to internal taper oral implants. MATERIAL AND METHODS: Forty-eight internally notched taper implants were divided into 2 groups of 24. Group OP received solid (1-piece) abutments; group TP received esthetic (2-piece) abutments. Each group was further subdivided into subgroups C (control) without mechanical loading and T (test) with mechanical loading. In groups OPC and TPC, the abutments were placed and removed and the removal torque values (RTVs) registered. In groups OPT and TPT, abutments were placed, mechanically loaded (500 000 cycles), removed, and the RTVs registered. Groups TPC and TPT were further tested for the traction force necessary to dislodge the abutment from the implant. For data analysis, the Student t test (for RTVs) and the Mann-Whitney U test (for TFVs) (α=.05) were performed. RESULTS: All abutments tested presented torque loss with RTVs lower than the placement torque. A statistically significant difference (P=.002) was found between groups OPC (81.6% of placement torque) and OPT mean RTVs results (85.0% of placement torque), while no statistical differences (P=.362) were found between groups TPC (63.7% of placement torque) and TPT (59.1% of placement torque). The traction force values necessary to dislodge the abutment from the implant, however, were significantly higher (P<.001) for group TPT than for group TPC. CONCLUSIONS: Cold welding did not occur in any of the abutment specimens tested. Even after the mechanical loading, esthetic abutments presented similar RTVs. The traction force necessary to remove esthetic abutments from inside the implants presented a 2-fold increase after mechanical loading.

Endocrown passo a passo: do laboratório à clínica / Endocrown step by step: from lab to clinic

A longevidade de um elemento tratado endodonticamente depende da quantidade, qualidade e da forma de reanatomização do remanescente dentário frente aos problemas encontrados pela perda da umidade, elasticidade e friabilidade decorrentes da remoção da polpa dentária. Uma alternativa conservadora encontrada na literatura é a endocrown, coroa maciça que apresenta margens circulares, com uma porção central correspondente à câmara pulpar preenchida integralmente com cerâmicas passíveis de condicionamento ácido. O presente estudo apresenta, em forma de caso clínico, o emprego e método de confecção clínica e laboratorial da técnica pela utilização de uma cerãmica de dissilicato de lítio que restaura o elemento de maneira funcional e estética

The longevity of an endodontically treated element depends on the quantity, quality and form of re-anatomization of the remaining tooth regarding the problems faced due to the moisture loss, elasticity and friability resulting from the dental pulp removal. A conservative alternative in the literature is the endocrown which features massive crown margin circular, with a central portion corresponding to the pulp chamber flled entirely with ceramic liable for acid etching. This study presents as a clinical case the preparation method of clinical and laboratory technique by using a ceramic lithium disilicate that restores the functional and aesthetic form of the element.