Assessment of Efficiency of Bioactive Glass, Self-Assembling Peptide, and Ozone Remineralising Agents on Artificial Carious Lesion

ABSTRACT Objective: To assess the efficacy of bioactive glass, self-assembling peptide, and ozone-remineralizing agents on the artificial carious lesion. Material and Methods: On the extracted 60 premolar teeth, an artificial carious lesion/demineralization was created. Later, the remineralization of demineralized teeth was done with respective remineralizing agents (Group A: Calcium sodium phosphosilicate (bioactive glass), Group B: Self-assembling peptide, Group C: Ozone remineralizing agents and Group D (Control): De ionized water. The degree of demineralization and remineralization were evaluated using the Vickers Hardness Number. Results: There was a decrease in microhardness from baseline to demineralization in all the groups, and this reduction was found to be statistically considerable. After the remineralization of demineralized samples with respective remineralizing agents, there was an increase in microhardness of 312.38, 276.67, and 254.42 in groups A, B, and C, respectively. In contrast, in Group D, there were no changes. Conclusion: Bioactive glass and self-assembling peptides had higher remineralizing capacities, which can be used to treat early carious lesions.

Evaluation of Root Fracture in endodontically treated Teeth using Cone Beam Computed Tomography.

AIM: Our objective was to perform an in vitro evaluation of root fracture in endodontically treated teeth using two cone beam computed tomography (CBCT) machines. MATERIALS AND METHODS: The sample comprised 86 single-rooted human premolars that had been fractured by a universal testing machine. The tomographic images were acquired using an Orthopantomograph OP300® and an Orthophos XG 3D® and evaluated by three examiners, by means of specific software. The teeth were classified into presence or absence of root fracture, then the root third where the fracture occurred, was determined. With regard to the detection of the fracture, the Kappa statistic was used for intra and interexaminer repro-ducibility at two distinct points in time. Chi-squared test was employed to analyze the sensitivity and specificity of the two tomographs (p < 0.05). RESULTS: The results showed a good or excellent Kappa index between examiners. As for the absolute frequency, the sensitivity (0.6) of the Orthophos XG 3D® equipment was superior, while specificity (0.91) was higher with the Orthopantomograph OP300®. On the receiver operating characteristics curve, moderate performance was found with an accuracy of 0.73 (OrthopantomographOP300®) and 0.74 (Orthophos XG 3D®) respectively. As far as the location of the root fracture is concerned, moderate agreement was verified using the Kappa statistic (k = 0.56). CONCLUSION: Although the regular CBCTs represent the imaging examination of choice for assisting root fracture diagnosis in endodontically treated teeth, their performance in this study demonstrated an imprecise diagnosis of fractures in a good many cases, irrespective of the tomography machine used. CLINICAL SIGNIFICANCE: An early and precise detection of root fractures is of the utmost clinical importance, but the radiopaque and/or metallic filling materials in the CBCT viewing field may generate artifacts, known as the beam-hardening effect, which could compromise root fracture detection.

Fractura radicular vertical / Vertical root fracture

El propósito de este reporte es presentar el caso de un paciente femenino con presencia de fractura radicular vertical (FRV) de un segundopremolar superior izquierdo, remitida a la clínica de Postgrado de Endodonciade la Universidad De La Salle Bajío para remoción de poste y retratamiento dental. Una vez realizado el diagnóstico se determinó FRV mediante sondeo minucioso irregular en un solo punto con sonda flexible, ligero dolor a la masticación y pérdida ósea radiográfica en forma de halo o gota, se sugirió como tratamiento extracción dental y cirugía exploratoria a petición del paciente

The aim of this report is to present the case of a female patient with a vertical root fracture (VRF) of a maxillary second premolar who was referred to the Postgraduate Endodontic Clinic of De La Salle Bajío University in León, Guanajuato, Mexico for the removal of a metallic post and retreatment of root canals. Examination via thorough irregular periodontal probing at a single point with a fl exible probe resulted in a diagnosis of VRF, slight pain on chewing, and radiographic bone loss in the shape of a halo or droplet, for which the suggested treatment was the extraction of the tooth, a surgical procedure that was subsequently performed at the patient’s request.

In vivo Evaluation of Proximal Resin Composite Restorations performed using Three Different Matrix Systems.

OBJECTIVE: The aim of this in vivo study was to radiographically evaluate the proximal contour of composite resin restorations performed using different matrix systems. MATERIALS AND METHODS: Patients with premolars needing class II type resin composite restorations involving the marginal ridge were selected. Thirty premolars were selected and randomly divided into three groups (n = 10 each) to receive restorations using different matrix systems: group 1: metal matrix coupled to a carrier matrix and wood wedge (G1-MMW); group 2: sectioned and precontoured metal matrix and elastic wedge (G2-SME); and group 3: a polyester strip and reflective wedge (G3-PMR). After the restorative procedure, bitewing radiographs were performed and analyzed by three calibrated professionals. The quality of the proximal contact and marginal adaptation of the proximal surfaces was classified as either correct or incorrect (undercontour/overcontour). RESULTS: The Pearson Chi-square statistical test (α = 5%) revealed a statistically difference between frequencies of correct and incorrect restorations (α(2) = 6.787, p < 0.05). The group G2 SME produced a higher frequency of correct proximal contours (90%), while G1-MMW and G3-PMR had a ratio of 40% correct and 60% incorrect contours respectively. CONCLUSION: None of the matrix systems was able to prevent the formation of incorrect proximal contours; however, the sectioned and precontoured metal matrix/elastic wedge configuration provided better results as compared to the other groups.

Avaliação de fraturas radiculares em imagens digitais com variações de angulagens / Evaluation of root fracture using digital images with angular

O objetivo da pesquisa foi avaliar a influência da variação da angulagem horizontal no diagnóstico de FRVs em dentes tratados endodonticamente. Vinte e dois pré-molares permanentes com raízes retas e ápices formados foram divididos em grupos: Grupo 01(controle): dois dentes, um deles com núcleo intrarradicular; Grupo 2: dez dentes com fratura; Grupo 3: dez dentes com fratura e núcleo intrarradicular. As amostras foram submetidas a testes de compressão com uma carga de 200 kg a uma velocidade de 0,5 mm / min. Radiografias periapicais foram obtidas (70 kVp, 10 mA, e tempo de exposição de 0,3 seg.) pelo Sistema Digora® em ângulos horizontais, na direção orto radial e com uma mudança de ângulo de 25º para a direita e para a esquerda. As imagens foram avaliadas por cinco endodontistas. O diagnóstico de dentes fraturados e não fraturados foi maior para o 1.º pré-molar (51,66%) que para o 2.º (43,1%). A presença de fratura vertical foi registrada em 60,9% e 66,7% para o 1.º e 2.º prémolares, respectivamente. A presença de fratura mostra associação estatisticamente significante com a presença de núcleo intrarradicular e a variação de angulagem no 2.º pré-molar (p-valor = 0,011). Esses resultados sugerem que variações na angulagem horizontal podem otimizar o diagnóstico de FRVs... (AU)

This study aimed to evaluate the influence of changing horizontal angle during periapical radiography on the diagnosis of VRFs in endodontically treated teeth. Twenty-two single-rooted premolars with straight root canals and apex formation were divided into groups: Group 1 (control) - two non-fractured teeth, one of them with intraradicular post; Group 2 - ten fractured teeth; and Group 3 - ten fractured teeth with intraradicular post. Specimens were subjected to compression testing with a load of 200 kg at a speed of 0.5 mm/min. Periapical radiographs were obtained (70 kVp, 10mA, and 0.3 sec exposure time) in a Digora™ system at horizontal angles in the orthoradial direction and with a 25º angle shift to the right and to the left. Images were evaluated by five endodontists. The diagnosis of fractured and non-fractured roots was higher for the first premolar (51.6%) than for the second premolar (43.1%). The presence of VRFs was recorded in 60.9% of cases for the first premolar, and in 66.7% for the second premolar. Presence of VRFs showed a statistically significant association with presence of intraradicular post and angle variation in the second premolar (p=0.011). These results suggest that changes in horizontal angulation, may optimize the diagnosis of VRFs... (AU)

Análise da influência das forças oclusais e fatores locais na morfologia das lesões cervicais não cariosas: estudo clínico transversal / Influence of occlusal forces and local factors in the morphology of noncarious cervical lesions: cross sectional trial

Objetivo: Analisar por meio de um estudo clinico transversal a influência das forças oclusais, assim como, de outros possíveis fatores locais na morfologia de lesões cervicais não cariosas (LCNC). Material e Método: Foram avaliados 32 indivíduos que possuíam LCNC nos primeiros pré-molares superiores, totalizando uma análise de 61 dentes, além disso, todos os sujeitos da pesquisa apresentavam todos os elementos dentais. Os mesmos eram pacientes regulares do serviço odontológico da Universidade Federal de Uberlândia, de ambos os gêneros, com idades entre 21 a 64. Para confirmação da morfologia e da severidade (profundidade) das LCNC, foi realizado exame cínico e replica das mesmas. As LCNC foram classificadas em anguladas ou arredondadas e em 3 níveis de severidade. A fim de determinar a presença de forças laterais, a presença de algum tipo de hábito parafuncional, como apertamento e bruxismo, foi analisado por meio de questionário e exame clinico. Também foram analisados, a presença de interferências oclusais (IO) em Relação Cêntrica (RC) e Movimentos excursivos, por meio de exame clinico de manipulação e análise dos modelos de gesso montados em articulador, assim como informações sobre a presença de facetas de desgaste. Além disso, informações sobre o periodonto, também foram coletadas, por meio de exame clinico, da mensuração das recessões gengivais no sentido cérvico-apical e mésio-distal. Assim como, da altura e espessura da cortical óssea vestibular, realizada por meio

de Tomografia Computadorizada do tipo Cone-Beam (TCCB). Resultados: Inicialmente, aplicou-se o teste de Shapiro wilk, para avaliar a normalidade dos dados. Para os dados normais, posteriormente, aplicou-se o teste de Kruskall-wallis. Enquanto, que para as variáveis que não apresentaram distribuição normal, foi aplicado o teste Mann- Whitney. Dados gerais da amostra, demonstraram que a idade apresentou associação tanto com a morfologia (p = ,016), quanto para a severidade das LCNC (p=,000). O que não foi encontrado para o gênero (morfologia, p =,139; severidade, p =,308), nem para a presença de algum distúrbio gástrico (morfologia, p =,260; severidade, p =,831). Além disso, nenhuma relação foi encontrada entre a preseça de hábitos parafuncionais ou alguma IO, com a morfologia e severidade das LCNC. Todos os sujeitos da pesquisa apresentaram facetas de desgaste, entretanto, a presença de uma ou duas facetas não influenciou a morfologia ou severidade das lesões. Já para a recessão gengival, associação significativa foi encontrada para a morfologia (p =,046). Em relação a altura e espessura da crista da cortical vestibular, a altura foi significante em relação a severidade (p= ,009), e a espessura da crista, apresentou associação com a morfologia (p=,001) e severidade (p=,044). Conclusão: Não houve associação direta entre a morfologia das LCNC e as forças oclusais, entretanto, a idade e o suporte ósseo (menor altura e cortical menos espessa), foram fatores determinantes para a prevalência de LCNC anguladas e mais severas

Objective: Analyze through a cross clinical study the influence of occlusal forces, as well as other possible local factors in the morphology of cervical lesions noncarious (LCNC). Material and Methods: We evaluated 32 individuals who had LCNC the first premolars, totaling an analysis of 61 teeth, moreover, all the subjects had complete dental arches. They were regular patients of the dental service at the Federal University of Uberlândia, of both genders, ages 21 to 64. To confirm the morphology and severity (depth) of LCNC was held cynical examination and replicates them. The LCNC were classified into angled or rounded and three severity levels. In order to determine the presence of lateral forces, the presence of some kind of habit parafuncional as bruxism and clenching was analyzed by questionnaire and clinical examination. Were also analyzed, the presence of occlusal interferences (OI) in Relation Centrica (CR) and movements excursive through clinical examination manipulation and analysis of plaster models mounted on articulator, as well as information about the presence of wear facets. In addition, information about periodontal were also collected through clinical examination, measurement of gingival recession in cervical-apical and mesiodistally. As well as the height and thickness of the buccal bone cortical held by Computed Tomography Cone-Beam type (TCCB). Results: Initially, we applied the Shapiro Wilk test to assess the normality of the data. For normal data, later applied the Kruskal-wallis test. While that for variables without normal distribution

the Mann-Whitney test was applied. General data of the sample, showed that age was associated with both the morphology (p =. 016), as to the severity of LCNC (p =.000). What was not found for the genre (morphology, p = .139; severity, p = 308), or to the presence of some gastric disorder (morphology, p = .260; severity, p = 831). Furthermore, no relationship was found between the preseça of parafunctional habits or some IO, with the morphology and severity of LCNC. All the subjects showed wear facets, however, the presence of one or two aspects not influence the morphology or severity of the lesions. As for the gingival recession, significant association was found for morphology (p =.046). Regarding the height and thickness of the crest cortical bone, the height was significant in relation to severity (p =.009), and the thickness of the crest, was associated with the morphology (p = .001) and severity (p = .044). Conclusion: There was no direct association between the morphology of NCCL and occlusal forces, however, the age and the bony support (lower thinner height and cortical), were determining factors for the prevalence of NCCL angled and more severe

Customized fiber glass posts. Fatigue and fracture resistance.

PURPOSE: To evaluate the root fracture strength of human single-rooted premolars restored with customized fiberglass post-core systems after fatigue simulation. METHODS: 40 human premolars had their crowns cut and the root length was standardized to 13 mm. The teeth were endodontically treated and embedded in acrylic resin. The specimens were distributed into four groups (n=10) according to the restorative material used: prefabricated fiber post (PFP), PFP+accessory fiber posts (PFPa), PFP+unidirectional fiberglass (PFPf), and unidirectional fiberglass customized post (CP). All posts were luted using resin cement and the cores were built up with a resin composite. The samples were stored for 24 hours at 37 degrees C and 100% relative humidity and then submitted to mechanical cycling. The specimens were then compressive-loaded in a universal testing machine at a crosshead speed of 0.5 mm/minute until fracture. The failure patterns were analyzed and classified. Data was submitted to one-way ANOVA and Tukey's test (alpha = 0.05). RESULTS: The mean values of maximum load (N) were: PFP - 811.4 +/- 124.3; PFPa - 729.2 +/- 157.2; PFPf- 747.5 +/- 204.7; CP - 762.4 +/- 110. Statistical differences were not observed among the groups. All groups showed favorable restorable failures. Fiberglass customized post did not show improved fracture resistance or differences in failure patterns when compared to prefabricated glass fiber posts.

Use of large-volume cone-beam computed tomography in identification and localization of horizontal root fracture in the presence and absence of intracanal metallic post.

INTRODUCTION: The objective of the study was to evaluate the ability of large-volume cone-beam computed tomography (CBCT) to detect horizontal root fracture and to test the influence of a metallic post. METHODS: Through the examination of 40 teeth by large-volume CBCT (20-cm height and 15-cm diameter cylinder) at 0.2-mm voxel resolution, 2 observers analyzed the samples for the presence and localization of horizontal root fracture. RESULTS: The values of accuracy in the groups that had no metallic post ranged from 33%-68%, whereas for the samples with the metallic post, values showed a wide variation (38%-83%). Intraobserver agreement showed no statistically significant difference between the groups with/without metallic post; both ranged from very weak to weak (kappa, 0.09-0.369). CONCLUSIONS: The low accuracy and low intraobserver and interobserver agreement reflect the difficulty in performing an adequate diagnosis of horizontal root fractures through a large-volume CBCT by using a small voxel reconstruction.

Treatment of oblique crown fractures in maxillary premolars using adhesive tooth fragment reattachment: 19 years of follow up.

This report presents an oblique crown fracture in the maxillary right premolars of an adolescent because of fall, which was treated using adhesive tooth fragment reattachment. The impact of the mandible base to the floor caused minor fractures in multiple teeth, severe fracture of teeth 14 and 15, and condylar fractures. The fragments of teeth 43, 45, 46, and 16 were lost at the site of accident. The condylar fractures were managed with a non-surgical conservative approach combining mandibular immobilization and stabilization of temporomandibular joints with maxillomandibular fixation using acrylic splints. After 3 months, the interocclusal splints were removed, and the patient was referred for dental care. Teeth 14 and 15 presented complicated oblique crown fractures causing separation of the buccal and palatal fragments, which were in place, attached to the gingival tissue. Tooth 15 presented chronic hyperplastic pulpits. The fragments were banded for stabilization during the endodontic treatment, and the bands served as matrix for adhesive tooth fragment reattachment. The other fractured teeth received direct composite resin restorations. After 8 years, tooth 16 developed pulp necrosis and was treated endodontically and restored with composite resin. Clinical and radiographic examination 19 years after trauma showed a good adaptation of the tooth fragment/composite resin restoration, good periodontal health, no signs of root resorption, and intact lamina dura.

Integrated treatment to resolve a horizontal root fracture.

Root fractures are defined as those that involve cement, dentin and pulp, comprising from 0.5 to 7% of injuries in permanent dentition. Diagnosis is made through clinical and radiographic exams, the latter frequently being limited by the position of the fracture. Treatment varies according to the displacement and vitality of the fragments. The authors present a clinical case of recurrent trauma of tooth 21 causing a horizontal root fracture in the middle third. After several attempts at endodontic treatment, the option was to remove the apical fragment by surgery. The postoperative period of 4 years shows very satisfactory results with regard to wound repair and tooth mobility, or implantation of the coronal segment.

Vertical root fracture in upper premolars with endodontic posts: finite element analysis.

Upper premolars restored with endodontic posts present a high incidence of vertical root fracture (VRF). Two hypotheses were tested: (1) the smaller mesiodistal diameter favors stress concentration in the root and (2) the lack of an effective bonding between root and post increases the risk of VRF. Using finite element analysis, maximum principal stress was analyzed in 3-dimensional intact upper second premolar models. From the intact models, new models were built including endodontic posts of different elastic modulus (E = 37 or E = 200 GPa) with circular or oval cross-section, either bonded or nonbonded to circular or oval cross-section root canals. The first hypothesis was partially confirmed because the conditions involving nonbonded, low-modulus posts showed lower tensile stress for oval canals compared to circular canals. Tensile stress peaks for the nonbonded models were approximately three times higher than for the bonded or intact models, therefore confirming the second hypothesis.

T-bar clasp-retained removable partial denture as an alternative to implant-based prosthetic treatment.

This article reports the case of a 55-year-old female patient who presented with unsatisfactory temporary crowns in the right mandibular premolars and molars, and a premolar-to-molar fixed partial denture in the left side. The clinical and radiographic examinations revealed a fracture of the left first premolar that was a retainer of the fixed partial denture and required extraction. Initially, the acrylic resin crowns were replaced by new ones, and a provisional RPD was made using acrylic resin and orthodontic wire clasps to resolve the problem arising from the loss of the fixed partial denture. Considering the patient's high esthetic demands, the treatment options for the definitive prosthetic treatment were discussed with her and rehabilitation with implant-supported dentures was proposed because the clinical conditions of the residual alveolar ridge were suitable for implant installation, and the patient's general health was excellent. However, the patient did not agree because she knew of a failed case of implant-retained denture in a diabetic individual and was concerned. The patient was fully informed that implant installation was the best indication for her case, but the arguments were not sufficient to change her decision. The treatment possibilities were presented and the patient opted for a clasp-retained removable partial denture (RPD) associated with the placement of crowns in the pillar teeth. The temporary RPD was replaced by the definitive RPD constructed subsequently. Although RPD was not the first choice, satisfactory esthetic and functional outcomes were achieved, overcoming the patient's expectations. This case report illustrates that the dentist must be prepared to deal with situations where, for reasons that cannot be managed, the patient does not accept the treatment considered as the most indicated for his/her case. Alternatives must be proposed and the functional and esthetic requirements must be fulfilled in the best possible manner.

Consequences and treatment after multiple avulsions of deciduous teeth--a case report.

The prevalence of traumatisms with avulsion of deciduous teeth varies from 7 to 13%, usually involving one tooth only. In this case report, a trauma with multiple losses of deciduous teeth and laceration of soft tissue is described as a consequence of a horse backward kick. After suture of extra-oral tissue wounds and application of anti-tetanic vaccine, the patient was referred to the emergency ambulatory of Sacred Heart University. Treatment procedures included radiographic analysis, removal of bone fragments and of a residual root of the tooth involved, remodeling and suture of intra-oral tissues. The patient was observed periodically and after full recovery, a prosthetic appliance was installed for functional and esthetic rehabilitation.

T-Bar clasp-retained removable partial denture as an alternative to implant-based prosthetic treatment

This article reports the case of a 55-year-old female patient who presented with unsatisfactory temporary crowns in the right mandibular premolars and molars, and a premolar-to-molar fixed partial denture in the left side. The clinical and radiographic examinations revealed a fracture of the left first premolar that was a retainer of the fixed partial denture and required extraction. Initially, the acrylic resin crowns were replaced by new ones, and a provisional RPD was made using acrylic resin and orthodontic wire clasps to resolve the problem arising from the loss of the fixed partial denture. Considering the patient's high esthetic demands, the treatment options for the definitive prosthetic treatment were discussed with her and rehabilitation with implant-supported dentures was proposed because the clinical conditions of the residual alveolar ridge were suitable for implant installation, and the patient's general health was excellent. However, the patient did not agree because she knew of a failed case of implant-retained denture in a diabetic individual and was concerned. The patient was fully informed that implant installation was the best indication for her case, but the arguments were not sufficient to change her decision. The treatment possibilities were presented and the patient opted for a clasp-retained removable partial denture (RPD) associated with the placement of crowns in the pillar teeth. The temporary RPD was replaced by the definitive RPD constructed subsequently. Although RPD was not the first choice, satisfactory esthetic and functional outcomes were achieved, overcaming the patient's expectations. This case report illustrates that the dentist must be prepared to deal with situations where, for reasons that cannot be managed, the patient does not accept the treatment considered as the most indicated for his/her case. Alternatives must be proposed and the functional and esthetic requirements must be fulfilled in...

Este artigo relata o caso de uma paciente de 55 anos que apresentava no arco mandibular coroas provisórias insatisfatórias nos pré-molares do lado direito e uma prótese parcial fixa de molar a pré-molar no lado esquerdo. Os exames clínico e radiográfico revelaram uma fratura do primeiro pré-molar esquerdo que era um retentor da prótese parcial fixa e teve a extração indicada. Inicialmente, as coroas provisórias foram substituídas por novas e uma prótese parcial removível provisória foi confeccionada com resina acrílica e grampos de fio ortodôntico a fim resolver os problemas relacionados à perda da prótese parcial fixa. Considerando a forte demanda estética da paciente, foram discutidas as opções de tratamento protético definitivo. Foi proposta a reabilitação com prótese implanto-suportada uma vez que as condições clínicas do rebordo alveolar se apresentavam adequadas para instalação de implantes e a saúde geral da paciente era excelente. Entretanto, a paciente não concordou com o tratamento proposto, alegando saber de um caso clínico em que houve insucesso na reabilitação por prótese implanto-suportada em um paciente diabético. Ela foi inteiramente informada de que a colocação de implantes era a melhor indicação para seu caso, mas os argumentos não foram suficientes para mudar sua decisão. As possibilidades de tratamento foram apresentadas e a paciente optou por uma prótese parcial removível (PPR) retida a grampos associada com coroas nos dentes pilares. Na seqüência, a PPR provisória foi substituída por uma PPR definitiva. Embora a PPR não tivesse sido a primeira escolha, foram obtidos resultados estéticos e funcionais satisfatórios, superando as expectativas da paciente. Este relato de caso ilustra que o dentista deve estar preparado para enfrentar situações em que, por razões que não possam ser administradas, o paciente não aceite o tratamento considerado mais indicado para seu caso. Alternativas devem ser propostas e as exigências...

Reaction of the lateral periodontium of dogs' teeth to contaminated and noncontaminated perforations filled with mineral trioxide aggregate.

It has been shown that the mineral trioxide aggregate (MTA) used to seal lateral/furcal perforations stimulates the deposition of newly formed cementum. Nevertheless, when the site of the perforation is contaminated, the healing process might occur under less favorable conditions. This study evaluated the repair healing process of noncontaminated and contaminated lateral perforations filled with MTA and the effect of previously filling the contaminated perforations with a bactericidal agent. Thirty lateral root perforations were prepared in endodontically treated dog's teeth, thus forming 3 groups with 10 specimens each. In group 1 the perforations were immediately sealed with MTA. In group 2 the perforations were left open for 7 days and thereafter sealed with MTA. In group 3 the perforations were left open for 7 days, filled temporarily with a calcium hydroxide-based paste for 14 days, and then sealed with MTA. The animals were killed after 90 days, and the pieces were prepared for histomorphologic and histomicrobiologic evaluations. The statistical analysis showed that group 1 had significantly better repair than groups 2 (P < .05) and 3 (P < .05), which validates the superior results obtained when MTA was immediately used to seal root perforations. Groups 2 and 3 had statistically similar repair to each other (P > .05). There were a larger number of cases of complete or partial biologic seal in group 1 compared with the contaminated groups. It might be concluded that the lateral root perforations sealed with MTA after contamination presented worse repair than the noncontaminated, immediately sealed perforations. The temporary filling with a bactericidal agent (calcium hydroxide-based paste) did not improve the repair of perforations exposed to contamination, and the contaminated groups presented similar results to each other.

Root resorption on torqued human premolars shown by tartrate-resistant acid phosphatase histochemistry and transmission electron microscopy.

OBJECTIVE: To identify clastic cells on the root surfaces of torqued human premolars. MATERIALS AND METHODS: A continuous force of 600 cNmm was applied to upper first premolars in patients 13-16 years of age by using a precise biomechanical model with superelastic wires (NiTi-SE). The 28 teeth in 14 patients were divided into five groups (control [nonmoved], and moved for either 1, 2, 3, or 4 weeks) and processed for tartrate-resistant acid phosphatase (TRAP) histochemistry and transmission electron microscopy. RESULTS: Mononuclear TRAP-positive cells appeared at 2 weeks, where as large multinucleated TRAP-positive cells were numerous at 3 and 4 weeks. Ultrastructural examination revealed many clastic cells in contact with resorption lacunae. In addition, some cementoblast-like cells appeared secreting new cementum over previously resorbed lacunae. CONCLUSIONS: In general, resorption lacunae and the number of clastic cells, which increased with the duration of the applied force, were found on the cementum surface at the pressure areas. Some signs of cementum repair were also noticed, even with the maintenance of the level of the force.

Fracture resistance of premolars restored with partial ceramic restorations and submitted to two different loading stresses.

This in vitro study evaluated the fracture resistance of teeth restored with different designs of partial ceramic restorations using two diameters of steel ball to apply fracture stresses. One hundred and twenty sound maxillary premolars were randomly divided into three groups of 40 elements; each group was submitted to one of three indirect restoration designs: inlay, onlay with only lingual cuspal coverage and onlay with buccal and palatal cuspal coverage. Another 20 intact teeth were randomly assigned as control groups. The restorations were produced with Super Porcelain EX-3 and Vitadur Alpha ceramics and luted according to manufacturers' instructions. The specimens were subjected to compressive axial loading in a universal testing machine at 0.5 mm/minute using two steel balls (3 and 10 mm in diameter), evaluating a total of 14 groups with 10 specimens each. Peak load to fracture was measured for each specimen. The results were submitted to analysis of variance and Tukey's test. Statistical analysis revealed that the inlays showed a significantly higher fracture resistance than both onlay designs, but with fracture resistance lower than that of intact teeth. Onlay fracture strength was equivalent for both designs. The force required to cause fracture with the 10-mm diameter ball was greater than with the 3-mm diameter ball. There were no differences between the tested ceramics.