Bone Behavior in Relation to the Depth of the Line of Marginal Cementation of Prostheses on Morse Cone Implants: Radiographic Evaluation in a Dog Model.

PURPOSE: This study was aimed at radiographically evaluating the effect of 3 different depths of the cementation line of prosthetic crowns on the bone response around Morse cone implants. MATERIAL AND METHODS: Five dogs underwent extractions of the lower premolars; after 3 months, placement of 30 implants, 3 mm apical to the bone level, was performed. Prefabricated cylinders of alumina, used as abutments, with 3 different transmucosal extension were cemented to the implants with zinc oxide-eugenol cement, determining the depth of the cementation lines (1.5 mm apically, and 0.5 and 2.5 mm coronally, respectively, to the bone level). In the control group, implants and abutments were placed without crowns, therefore, with no cementation line. RESULTS: The results showed no statistically significant differences between the control and test groups regarding the different depths of the cementation line both mesially (P = 0.18) and distally (P = 0.50). CONCLUSION: Different depths of cementation did not affect the behavior of marginal bone, indicating that crowns can be cemented with zinc oxide-eugenol cement at any distance or even at the bone level without disturbing bone healing around Morse cone implants.

Comparative histological and histomorphometrical evaluation of marginal bone resorption around external hexagon and Morse cone implants: an experimental study in dogs.

PURPOSE: Aim of this study was to evaluate the histological and histomorphometrical differences at the marginal bone level with the use of 2 different implant-abutment assembly designs (the traditional External Hexagon and the Morse Cone tapered connections). METHODS: Nine Morse Cone and 9 External Hexagon implants were inserted in 6 mongrel dogs. The Morse Cone implants were installed 2 mm below the crestal bone level, whereas the External Hexagon flush. The implants were retrieved after 2 months. Mean distance between the original level of coronal bone to the top of the implant and the mean distance between the top of the implant and the first bone-to-implant contact (fBIC) were recorded. RESULTS: No significant differences were found when the mean distance between the original level of coronal bone to the top of the implant was evaluated; however, there were statistically significant differences in the mean distances between the top of the implants and fBIC, suggesting a smaller amount of bone loss or remodeling in the Morse Cone compared to the External Hexagon group. CONCLUSION: Subcrestal placement had a positive impact on crestal bone remodeling in Morse Cone implants.

Ultrastructural analysis of bone formation around dental implants in nondiabetic rats, severe diabetics not controlled and controlled with insulin.

PURPOSE: To evaluate bone formation through ultrastructural analysis around titanium implants in severe alloxanic uncontrolled diabetic rats, and controlled with insulin, in comparison with nondiabetic rats. METHODS: Thirty-six male Wistar rats, weighing between 200 and 300 g, divided into three experimental groups: normal control group (G1), a diabetic group without treatment (G2), and a diabetic group treated with insulin (G3). The animals received titanium implants in the right femur, and osseointegration was evaluated at 7, 14, and 21 days after surgery, through ultrastructural analysis using scanning electron microscopy. RESULTS: The ultrastructural analysis showed a dense bone structure in the G1, few empty spaces and a small number of proteoglycans; G2 presented bone matrix with a loose aspect, irregular arrangement, thin trabeculae, empty spaces and a large number of proteoglycans; G3 obtained similar results to G1, however with a higher number of proteoglycans. CONCLUSION: Severe diabetes caused ultrastructural changes in bone formation, and insulin therapy allowed an improvement in osseointegration, but it was not possible to reach the results obtained in the control group.

Association between sleep bruxism and temporomandibular disorders: a polysomnographic pilot study.

The aim of this study was to verify the association between sleep bruxism (SB) and temporomandibular disorders (TMD) in a sample of 14 TMD patients and 12 healthy control subjects. All participants were evaluated using a clinical questionnaire, visual analog scale (VAS) for TMJ/muscle palpation, and by functional examination. The experimental group was divided into three TMD subgroups: joint sounds and pain, muscular tenderness, and mixed diagnosis. All participants underwent polysomnographic recording (PSG). A second clinical examination was then carried out to verify the relationship between rhythmic masticatory muscle activity and pain/tenderness on the following morning. The experimental and control groups presented VAS mean scores of 36.85 +/- 23.73 mm and 0 mm, respectively. The presence of SB was neither associated with TMD (p > 0.05) nor with pain on palpation (p > 0.05). Further research with a more representative sample of each TMD subgroup is necessary to elucidate its interaction with SB.

The treatment of painful temporomandibular joint clicking with oral splints: a randomized clinical trial.

BACKGROUND: The authors compared the efficacy of bilateral balanced and canine guidance (occlusal) splints in the treatment of temporomandibular joint (TMJ) pain in subjects who experienced joint clicking with a nonoccluding splint in a double-blind, controlled randomized clinical trial. METHODS: The authors randomly assigned 57 people with signs of disk displacement and TMJ pain into three groups according to the type of splint: bilateral balanced, canine guidance and nonoccluding. The authors followed the groups for six months using analysis of a visual analog scale (VAS), palpation of the TMJ and masticatory muscles, mandibular movements and joint sounds. They used repeated analysis of variance and a chi(2) test to test the hypothesis. RESULTS: The type of guidance used did not influence the pain reduction, yet both occlusal splints were superior to the nonoccluding splint, on the basis of the VAS. Despite similar outcomes in relation to opening, left lateral and protrusive movements, TMJ and muscle pain on palpation, subjects who used the occlusal splints had improved clinical outcomes. The frequency of joint noises decreased over time, with no significant differences among groups. Subjects in the groups using the occlusal splints reported more comfort. CONCLUSION: The type of lateral guidance did not influence the subjects' improvement. All of the subjects had a general improvement on the VAS, though subjects in the occlusal splint groups had better results that did subjects in the nonoccluding splint group.

Ultrastructural analysis of bone formation around dental implants in nondiabetic rats, severe diabetics not controlled and controlled with insulin

Abstract Purpose: To evaluate bone formation through ultrastructural analysis around titanium implants in severe alloxanic uncontrolled diabetic rats, and controlled with insulin, in comparison with nondiabetic rats. Methods: Thirty-six male Wistar rats, weighing between 200 and 300 g, divided into three experimental groups: normal control group (G1), a diabetic group without treatment (G2), and a diabetic group treated with insulin (G3). The animals received titanium implants in the right femur, and osseointegration was evaluated at 7, 14, and 21 days after surgery, through ultrastructural analysis using scanning electron microscopy. Results: The ultrastructural analysis showed a dense bone structure in the G1, few empty spaces and a small number of proteoglycans; G2 presented bone matrix with a loose aspect, irregular arrangement, thin trabeculae, empty spaces and a large number of proteoglycans; G3 obtained similar results to G1, however with a higher number of proteoglycans. Conclusion: Severe diabetes caused ultrastructural changes in bone formation, and insulin therapy allowed an improvement in osseointegration, but it was not possible to reach the results obtained in the control group.

Effect of experimental chewing on masticatory muscle pain onset.

OBJECTIVES: To evaluate the effect of a chewing exercise on pain intensity and pressure-pain threshold in patients with myofascial pain. METHODS: Twenty-nine consecutive women diagnosed with myofascial pain (MFP) according to the Research Diagnostic Criteria comprised the experimental group and 15 healthy age-matched female were used as controls. Subjects were asked to chew a gum stick for 9 min and to stay at rest for another 9 min afterwards. Pain intensity was rated on a visual analog scale (VAS) every 3 min. At 0, 9 and 18 min, the pressure-pain threshold (PPT) was measured bilaterally on the masseter and the anterior, medium, and posterior temporalis muscles. RESULTS: Patients with myofascial pain reported increase (76%) and no change (24%) on the pain intensity measured with the VAS. A reduction of the PPT at all muscular sites after the exercise and a non-significant recovery after rest were also observed. CONCLUSION: The following conclusions can be drawn: 1. there are at least two subtypes of patients with myofascial pain that respond differently to experimental chewing; 2. the chewing protocol had an adequate discriminative ability in distinguishing patients with myofascial pain from healthy controls.

Influence of the menstrual cycle on the pressure pain threshold of masticatory muscles in patients with masticatory myofascial pain.

OBJECTIVE: The aim of this study was to investigate the influence of the menstrual cycle and oral contraceptive (OC) intake on the pressure pain threshold (PPT) of masticatory muscles in patients with masticatory myofascial pain (MFP). STUDY DESIGN: The sample was composed of 36 women, divided into 4 groups, according to the presence of MFP and the intake of OC (15 patients had MFP [7 taking OC] and 21 were pain-free controls [8 taking OC]). The algometer-based PPT of masseter and temporalis, and the record of subjective pain by visual analog scale (VAS) were determined during 2 consecutives menstrual cycles at 4 phases (menstrual, follicular, periovulatory, and luteal). A 3-way ANOVA for repeated measurements, Kruskal-Wallis, Friedman, and Dunn tests, with a 5% significant level analyzed the data. RESULTS: PPT was significantly lower in MFP patients when compared with controls throughout the experiment (P < .001). The menstrual phases did not influence PPT (P > .05), while the intake of OC seems to raise PPT levels for the left temporalis (P = .01) and right masseter (P = .04). VAS was, in general, higher at the menstrual phase CONCLUSIONS: Different phases of the menstrual cycle have no influence on PPT values, regardless of the presence of a previous condition, as masticatory myofascial pain, while the intake of OC is associated with decreased levels of reported pain.

Evaluation of dry needling and 0.5% lidocaine injection therapies in myofascial pain trigger points in masticatory muscles

OBJECTIVE: The purpose of this study was to compare the effectiveness of trigger points injections using lidocaine 0.5% and dry needling without any kind of home-based rehabilitation program. METHODS: Sixteen patients with myofascial pain and trigger points in masticatory muscles were randomly assigned to two groups and received only one application session. The pressure pain threshold (PPT) was recorded before and after the injection: Ten minutes, 24 hours later, 7, 15, 21 and 30 days after the treatment. Visual analogue scale (VAS) was used to in all evaluation periods. RESULTS: There were no difference between groups for PPT, but for all groups the PPT during the time significantly increased when compared the before treatment. VAS showed differences between groups and during the time. The 0.5% lidocaine had the lowest VAS values when compared to dry needling, but at 30 days there were no differences among them. CONCLUSIONS: Despite the differences in VAS and considering there were no differences in PPT increases, we concluded that, in this study, both groups were able to disrupt the mechanisms of trigger point and relieve the myofascial pain symptoms.

Effect of silica coating and silanization on flexural and composite-resin bond strengths of zirconia posts: An in vitro study.

STATEMENT OF PROBLEM: The bond strength of composite resin cores to the smooth surface of prefabricated zirconia-based ceramic posts is problematic because it might not be sufficient to ensure stability of the post-and-core system. It is also not clear whether any alteration of the post surface to provide additional mechanical or chemical retention would compromise flexural strength of the posts. PURPOSE: This study tested the effect of a tribochemical treatment on the bond strength (BS) between zirconia-based ceramic posts and composite resin and on the flexural strength (FS) of the posts. MATERIAL AND METHODS: For the BS test, 2 groups of specimens (n = 10) were prepared as follows: In the experimental (E) group, zirconia-based ceramic posts (Cosmopost), 21 mm long and 1.7 mm in diameter, were treated with a tribochemical silica coating and silanization system (Rocatec). For the control (C) group, zirconia-based ceramic posts were used as supplied by the manufacturer. For the 2 groups, posts were centered and vertically positioned in a metal mold, and composite resin (Tetric Ceram) was polymerized around the posts to form rings (6 mm diameter x 4 mm height). All specimens were positioned in a universal testing machine, and a load was applied axially on the protruding heads of posts in a shear push-out mode test until bond failure (MPa). Fracture mode was assessed as cohesive, cohesive/adhesive, or adhesive. Following this, the FS of the posts was measured in MPa using a 3-point bending test. Data were recorded and statistically analyzed using the Student t test for both tests (alpha = .01). RESULTS: Mean fracture load values +/- SDs for the BS test were 28.1 +/- 2.3 MPa and 8.9 +/- 3.97 MPa for the E and C groups, respectively. The mean FS values were 1544.9 +/- 214.1 MPa and 844.8 +/- 50.8 MPa for the E and C groups, respectively. The tribochemically treated posts exhibited significantly higher values for both bond strength to composite resin and resistance to fracture when compared to posts in the control group (P < .001). Fracture analysis showed 100% cohesive/adhesive fractures for group E specimens and 100% adhesive fractures for group C specimens. CONCLUSIONS: The use of a tribochemical silica coating process and silanization on zirconia-based ceramic posts increased both the bond strength to composite resin as well as the fracture strength of posts.

Effect of cyclic loading on fracture strength of endodontically treated teeth restored with conventional and esthetic posts.

INTRODUCTION: Esthetic post and core systems were recently introduced. There are few reports regarding their behavior under cyclic loading. OBJECTIVES: This study compared the effect of cyclic loading on survival rate, residual strength and mode of fracture of endodontically treated teeth restored with esthetic and direct metallic post systems subjected to mechanical cyclic loading. MATERIALS AND METHODS: Thirty canines were endodontically treated, decoronated and prepared for metal free ceramic crowns, leaving 1.5 mm of dentin for ferrule effect. They were distributed in 3 groups and restored as follows: group 1 with zirconia posts (Cosmopost) and glass-ceramic cores (IPS Empress Cosmopost); group 2 with fiber reinforced composite posts (FibreKor) and group 3 with titanium posts (AZthec Anchor). Direct resin composite (Build It FR Resin Composite) was used as core in groups 2 and 3. All specimens were restored with all ceramic crowns (IPS Empress 2). A resin cement/adhesive system (Cement It/Bond It Primer A+B) was used to lute the posts to root canals and metal free porcelain crowns to the teeth preparation. Specimens were subjected to mechanical load of 250 N for 500,000x at a frequency of 1.7 Hz and then to static load until failure in a universal testing machine. Data were analyzed using One-way ANOVA and Fischer Exact tests alpha=0.05. RESULTS: All groups had 100% survival rate after cyclic loading; fracture strength values (SD) in N were: group 1 = 886.5(170.6), group 2 = 762.2(113.6) and group 3 = 768.9(72.9); there was no difference among groups (p=0.08); the percentage of mode of favorable fracture found was: group 1 = 60%, group 2 = 90% and group 3 = 50%; there was no correlation between the mode of failure and post and core system used (P=0.142). CONCLUSIONS: Esthetic post and core systems showed statistically equivalent fracture strength values, mode of failure and survival rate compared to conventional direct metallic post and resin composite core system after cyclic loading.

Effect of experimental chewing on masticatory muscle pain onset

OBJECTIVES: To evaluate the effect of a chewing exercise on pain intensity and pressure-pain threshold in patients with myofascial pain. METHODS: Twenty-nine consecutive women diagnosed with myofascial pain (MFP) according to the Research Diagnostic Criteria comprised the experimental group and 15 healthy age-matched female were used as controls. Subjects were asked to chew a gum stick for 9 min and to stay at rest for another 9 min afterwards. Pain intensity was rated on a visual analog scale (VAS) every 3 min. At 0, 9 and 18 min, the pressure-pain threshold (PPT) was measured bilaterally on the masseter and the anterior, medium, and posterior temporalis muscles. RESULTS: Patients with myofascial pain reported increase (76 percent) and no change (24 percent) on the pain intensity measured with the VAS. A reduction of the PPT at all muscular sites after the exercise and a non-significant recovery after rest were also observed. CONCLUSION: The following conclusions can be drawn: 1. there are at least two subtypes of patients with myofascial pain that respond differently to experimental chewing; 2. the chewing protocol had an adequate discriminative ability in distinguishing patients with myofascial pain from healthy controls.

Partial time use of anterior repositioning splints in the management of TMJ pain and dysfunction: a one-year controlled study.

This study aimed at evaluating the effectiveness of partial use of anterior repositioning appliances in the management of TMJ pain and dysfunction when compared to stabilization splints and a control group in a one-year follow-up. Sample was initially constituted by 60 patients, randomly divided into three groups: I- stabilization splints, II- repositioning splints and III- no treatment. The whole sample was evaluated by means of TMJ and muscle palpation, mandibular AROM, analysis of occlusal contacts, joint sounds inspection and Visual Analogue Scale (VAS) for one year; 52 patients composed the final sample. A significant (after 15 days) improvement in pain report (VAS) and palpation index was found for group II (p < or = 0.01). The occurrence of occlusal alterations as posterior open bite or gross interferences after the splint therapy and increased muscle tenderness were not problems in this study. Similar results in joint noises reduction were observed for the entire sample. It was concluded that controlled partial use of repositioning splints is a beneficial tool in the management of intra-articular pain and dysfunction, with no risks of irreversible occlusal changes.

Influência da elevação do retalho, durante a instalação de implantes imediatos, na remodelação óssea peri-implantar / Influence of flap elevation during immediate implant placement on peri-implant bone remodeling

Verificar a influência dos retalhos cirúrgicos na formação óssea peri-implantar. Métodos: quatro pré-molares da arcada inferior de sete cães, de raça não definida, foram extraídos, e quatro implantes imediatos foram instalados. Os grupos foram divididos em G1, sem retalho, e G2, com elevação de retalho de espessura total, totalizando 14 implantes em cada grupo. Após quatro meses, realizou-se a coleta das amostras e a análise histomorfométrica, a fim de se observar contato osso-implante (BIC) vestibular, BIC total, área vestibular e área total de todos os implantes. Para análise estatística intergrupos utilizou-se o teste de Mann-Whitney (p < 0,05). Resultados: observou-se que o grupo referente aos implantes instalados sem elevação de retalho apresentou melhores taxas de BIC, tanto na face vestibular quanto no BIC total. Os dados também mostraram-se superiores estatisticamente em prol do grupo sem retalho, quanto à área óssea na face vestibular dos implantes. Conclusão: conclui-se que a técnica cirúrgica sem retalho têm influência favorável na formação óssea ao redor dos implantes...

The aim of this study was to assess the influence of surgical flaps over boneformation around implants. Methods: Seven mongrel dogs had four mandibular pre-molars extracted and four immediate implants placed. The experimental groups were divided into G1 (flapless) and G2 (full-thickness flap), totaling 14 implants in each group. After four months, samples were collected and histomorphometric analysis was carried out with a view to assessing buccal bone-to-implant contact (BIC), total BIC, buccal area, and total area of all implants. For intergroup statistical analysis, Mann-Whitney test was applied (p < 0.05). Results: The group comprising implants without flap elevation had better BIC rates, both buccal and total BIC, than the flap elevation group. Additionally,data yielded better results in favor of the group without flap, which was statistically significant, particularly with regard to bone formation on the buccal surface of implants. Conclusion: The flapless surgical technique produces favorable effects on bone formation around implants...

Orofacial pain: basic mechanisms and implication for successful management.

Orofacial Pain is the field of dentistry devoted to the diagnosis and management of chronic, complex, facial pain and oromotor disorders. This specialty in dentistry has developed over a number of years out of the need for better understanding of a group of patients who somehow were not clearly suffering from dental pain disorders, but still did not seem to have a clearly defined medical problem. After a long period of treating patients based on the mechanicist aspect of the disease, our profession has realized the importance of basic knowledge and differencial diagnosis in order to proper manage these patients. This modification in the approach has caused severe changes in education as well as in clinical activities. Historically considered as a problem of occlusion, Orofacial Pain, including Temporomandibular Disorders (TMD) has recently reached the status of "Specialty" in Brazil. Therefore, this paper aims to discuss the main differences between musculoskeletal and neuropathic pain and the importance of basic knowledge to perform successful management.

Ressonância magnética nos desarranjos internos da ATM: sensibilidade e especificidade / Ressonância magnética nos desarranjos internos da ATM: sensibilidade e especificidadeDiagnosis of TMJ disorders by magnetic resonance imaging: sensitivity and specificity

OBJETIVO: esta revisão de literatura visa avaliar, através de literatura específica, a sensibilidade e especificidade do exame de ressonância magnética (RM) para o diagnóstico dos desarranjos internos da articulação temporomandibular (ATM). METODOLOGIA: tanto artigos que utilizaram ATM de cadáveres para comparar achados anatômicos aos achados de ressonância magnética (RM), como artigos que compararam achados clínicos com achados de RM foram utilizados. Através dos achados desses artigos, as propriedades de sensibilidade e especificidade da RM para o diagnóstico de desarranjos internos da ATM foram calculadas. Com isso, a confiabilidade e a aplicabilidade do exame de RM no diagnóstico dos desarranjos internos da ATM foram discutidas. RESULTADOS: encontrou-se sensibilidade de 90 por cento e especificidade de 88 por cento da RM para desarranjos internos da ATM. CONCLUSÃO: o exame de RM de ATM possui ótima sensibilidade e especificidade para o diagnóstico dos desarranjos internos da ATM. Porém, tal exame deve ser solicitado com cautela, apenas nos casos onde a imagem seja indispensável para o plano de tratamento.

OBJECTIVE: the aim of this paper is to review the literature concerning the reliability and applicability of magnetic resonance imaging (MRI) in the diagnosis of temporomandibular joint (TMJ) internal disorders. METHODS: articles that have used TMJ from cadavers to compare MRI findings with anatomic findings, as well as some papers that have compared clinical findings with MRI findings were evaluated. According to the findings identified on these articles, the MRI sensitivity and specificity properties for the TMJ internal disorders diagnosis were calculated. Then, the MRI reliability and applicability for the TMJ internal disorders diagnosis were discussed. RESULTS: 90 percent of sensitivity and 88 percent of specificity were found. CONCLUSION: the TMJ MRI presents good sensitivity and specificity for the TMJ internal disorders diagnosis. But dentists should beware and request this exam only in cases where MRI will be essential to the treatment planning.

Prevalência das facetas de desgaste e sua relação com aspectos oclusais e hábitos parafuncionais / Prevalence of dental wear and their relation to occlusal aspects and parafunctional habits

Este estudo avalia a prevalência, extensão e severidade das facetas de desgaste em 60 alunos do primeiro ano dos cursos de Odontologia e Fonoaudiologia da Universidade de São Paulo, campus Bauru, com idades entre 17 e 24 anos. Questionários e exames clínicos foram realizados sendo que as facetas de desgaste foram avaliadas intra-oralmente e através de modelos de gesso. Todos os alunos apresentaram facetas de desgaste, sendo os caninos os dentes mais afetados (26,46%). A variável gênero não apresentou associação estatística com as lesões avaliadas. Dentre os prováveis fatores contribuintes examinados observou-se uma relação estatística nos pré-molares esquerdos com as facetas nos estudantes que apresentavam função em grupo nos movimentos excursivos (p = 0,007). Com relação aos hábitos parafuncionais encontrou-se correlação estatística entre o hábito de apertamento (p = 0,044) e desgaste nos incisivos esquerdos e entre o hábito de ranger e o desgaste nos caninos esquerdos (p = 0,006) e direitos (p = 0,009).

This study aimed to evaluate the prevalence, extension and severity of dental wear in 60 students (age between 17 and 24 years-old), attending, the undergraduate programs of the Bauru School of Dentistry, University of São Paulo. Questionnaires about parafunctional activity, clinical evaluation and analysis of study models were performed for this purpose. All students presented dental wears, regardless of gender or aging. The canines were the more affected group of teeth (26.46%). A significant association was found between wear facets and group function in excursive laterals movements (p = 0.007) for left premolars. Significant association was also detected between clenching and the attrition on left incisors(p = 0.044) and between grinding and the attrition on left (p = 0.006) and right canines (p = 0.009).

Quantidade de pressão e padrão de dor referida em pacientes portadores de dor miofascial / Pressure pain treshold and referred pain pattern in myofascial pain patients

Os propósitos deste estudo foram: determinar a quantidade de pressão que estimulasse resposta dolorosaem pacientes com pontos gatilho (PG) quando comparado ao grupo controle assintomático; determinar umintervalo de tempo de manutenção de pressão para que houvesse o surgimento do processo de dor referida(DR) e verificar o padrão de DR provocada. Selecionou-se 24 pacientes portadores de dor miofascial e parao grupo controle, 20 indivíduos livres de qualquer sintomatologia de disfunção temporomandibular. Ambos os grupos foram examinados por um único examinador em pontos gatilho previamente diagnosticados. Noitem quantidade de pressão, o intervalo no grupo portador de dor miofascial foi significantemente menor queo grupo controle. O padrão de DR obtido confere com aquele descrito na literatura. Os autores deste estudoconcluíram que o limiar de dor a palpação em portadores de dor miofascial é menor que em indivíduos nãoportadores e o padrão da manifestação de DR semelhante ao descrito na literatura.

The purposes of this study were: to determine the amount of pressure necessary to create painful responsein patients with myofascial pain in head and neck when compared with a assintomatic control group; to determineone sustained pressure time that causes referred pain and to determine the referred pain pattern whenthe trigger points were stimulated. The group A was formed by 24 patients who had myofascial pain, andgroup B was composed by 20 myofascial pain free subjects. For both groups, examination was performed byonly an experienced and trained professional. Group A had lower pressure pain threshold when comparedwith group B.( p < 0,01) The referred pain patterns was very similar to those described in literature. It wasconcluded that the pressure pain threshold in myofascial pain patients is lower than pressure pain thresholdin non-patients.

Effect of cyclic loading on fracture strength of endodontically treated teeth restored with conventional and esthetic posts

INTRODUCTION: Esthetic post and core systems were recently introduced. There are few reports regarding their behavior under cyclic loading. OBJECTIVES: This study compared the effect of cyclic loading on survival rate, residual strength and mode of fracture of endodontically treated teeth restored with esthetic and direct metallic post systems subjected to mechanical cyclic loading. MATERIALS AND METHODS: Thirty canines were endodontically treated, decoronated and prepared for metal free ceramic crowns, leaving 1.5 mm of dentin for ferrule effect. They were distributed in 3 groups and restored as follows: group 1 with zirconia posts (Cosmopost) and glass-ceramic cores (IPS Empress Cosmopost); group 2 with fiber reinforced composite posts (FibreKor) and group 3 with titanium posts (AZthec Anchor). Direct resin composite (Build It FR Resin Composite) was used as core in groups 2 and 3. All specimens were restored with all ceramic crowns (IPS Empress 2). A resin cement/adhesive system (Cement It/Bond It Primer A+B) was used to lute the posts to root canals and metal free porcelain crowns to the teeth preparation. Specimens were subjected to mechanical load of 250 N for 500,000x at a frequency of 1.7 Hz and then to static load until failure in a universal testing machine. Data were analyzed using One-way ANOVA and Fischer Exact tests alpha=0.05. RESULTS: All groups had 100 percent survival rate after cyclic loading; fracture strength values (SD) in N were: group 1 = 886.5(170.6), group 2 = 762.2(113.6) and group 3 = 768.9(72.9); there was no difference among groups (p=0.08); the percentage of mode of favorable fracture found was: group 1 = 60 percent, group 2 = 90 percent and group 3 = 50 percent; there was no correlation between the mode of failure and post and core system used (P=0.142). CONCLUSIONS: Esthetic post and core systems showed statistically equivalent fracture strength values, mode of failure and survival rate compared to conventional...

INTRODUÇÃO: Os sistemas de núcleos intra-radiculares estéticos foram recentemente introduzidos no mercado. Não existem muitos trabalhos na literatura comparando seu comportamento em relação aos sistemas de pinos metálicos convencionais quando submetidos à testes com carga cíclica. OBJETIVOS: este estudo comparou a taxa de sobrevivência, resistência à fratura e modo de fratura de dentes tratados endodonticamente reconstruídos com sistemas de núcleos intra-radiculares metálicos convencionais e estéticos, restaurados com coroas de porcelana pura e submetidos à carga cíclica. MATERIAIS E MÉTODOS: trinta caninos tiveram as coroas removidas 1,5mm acima da junção cemento-esmalte e preparados para coroa de porcelana pura deixando 1,5mm de dentina acima do término do preparo. Os dentes foram distribuídos em 3 grupos de 10. O grupo 1 foi restaurado com pinos de cerâmica de zircônia e núcleos de preenchimento em cerâmica vítrea termo-injetada. O grupo 2 foi restaurado com pinos de resina composta reforçada por fibra de vidro e o grupo 3 com pinos de titânio. Nos grupos 2 e 3 foi usada resina composta reforçada com fibra de vidro como material para núcleo de preenchimento; os dentes foram restaurados com coroas totais e tanto os pinos quanto as coroas de porcelana foram cimentados com um sistema de cimentação resinosa de polimerização dupla. Os espécimes foram incluídos em resina acrílica e submetidos à uma carga de 250N por 500,000 ciclos, numa freqüência de 1,7Hz sendo em seguida submetidos à carga estática em uma máqina de testes universal até a falha. Os dados foram analisados estatisticamente com os testes ANOVA a 1 critério e Exato de Fischer (alfa=.05). RESULTADOS: a taxa de sobrevivência foi de 100 por cento; os valores de resistência à fratura em N (DP) foram: grupo 1 = 886,50(170,6), grupo 2 = 762,2(113,6) e grupo 3 = 768,9(72,9). Não houve diferença estatística de resistência à fratura entre os grupos (P=0.08). O percentual de modo de...

Effect of cyclic loading on fracture strength of endodontically treated teeth restored with conventional and esthetic posts%Efeito da carga cíclica na resistência de dentes tratados endodonticamente restaurados com pinos dentários convencionais e estéticos

INTRODUÇÃO: Os sistemas de núcleos intra-radiculares estéticos foram recentemente introduzidos no mercado. Não existem muitos trabalhos na literatura comparando seu comportamento em relação aos sistemas de pinos metálicos convencionais quando submetidos à testes com carga cíclica. OBJETIVOS: este estudo comparou a taxa de sobrevivência, resistência à fratura e modo de fratura de dentes tratados endodonticamente reconstruídos com sistemas de núcleos intra-radiculares metálicos convencionais e estéticos, restaurados com coroas de porcelana pura e submetidos à carga cíclica. MATERIAIS E MÉTODOS: trinta caninos tiveram as coroas removidas 1,5mm acima da junção cemento-esmalte e preparados para coroa de porcelana pura deixando 1,5mm de dentina acima do término do preparo. Os dentes foram distribuídos em 3 grupos de 10. O grupo 1 foi restaurado com pinos de cerâmica de zircônia e núcleos de preenchimento em cerâmica vítrea termo-injetada. O grupo 2 foi restaurado com pinos de resina composta reforçada por fibra de vidro e o grupo 3 com pinos de titânio. Nos grupos 2 e 3 foi usada resina composta reforçada com fibra de vidro como material para núcleo de preenchimento; os dentes foram restaurados com coroas totais e tanto os pinos quanto as coroas de porcelana foram cimentados com um sistema de cimentação resinosa de polimerização dupla. Os espécimes foram incluídos em resina acrílica e submetidos à uma carga de 250N por 500,000 ciclos, numa freqüência de 1,7Hz sendo em seguida submetidos à carga estática em uma máqina de testes universal até a falha. Os dados foram analisados estatisticamente com os testes ANOVA a 1 critério e Exato de Fischer (a=.05). RESULTADOS: a taxa de sobrevivência foi de 100%; os valores de resistência à fratura em N (DP) foram: grupo 1 = 886,50(170,6), grupo 2 = 762,2(113,6) e grupo 3 = 768,9(72,9). Não houve diferença estatística de resistência à fratura entre os grupos (P=0.08). O percentual de modo de fratura favorável encontrado foi: grupo 1 = 60%; grupo 2 = 90% e grupo 3 = 50%. Não houve correlação entre o tipo de pino e modo de fratura (P=0.142). CONCLUSÃO: dentes restaurados com sistemas de núcleos intra-radiculares estéticos e coroas totais de porcelana tiveram as mesmas taxas de sobrevivência, valores de resistência à fratura e modo de fratura que os metálicos convencionais diretos após aplicação de carga cíclica