Longevity of different abutments placed on narrow diameter implants: Assessment of structural damage and loosening.

OBJECTIVES: To evaluate structural damage and loosening of abutments placed on narrow diameter implants after cyclic fatigue. METHODS: Sixty Morse taper narrow diameter implants (Neodent, Brazil) received two types of abutments (1PA- one-piece abutment or 2PA- two-piece abutment), which were randomly divided into 3 fatigue experiments (n = 10). The implants were placed into a customized supporting holder and a software-assisted digital torque wrench secured the manufacturer recommended torque for each abutment. Cone beam computed tomography (CBCT) scans were acquired, before and after fatigue, and post-processed (software e-Vol DX) to assess damage and abutment displacement. The boundary fatigue method was adapted to use 2 × 106 cycles, 2 Hz of frequency and constant peak load of 80 N (first experiment) that varied according to the failure rate of previous specimens (second and third experiments). Failure was evaluated using CBCT scans and removal torque values. Data were used to estimate long-term torque degradation, probability of failure and Weibull modulus (software ALTA PRO9). RESULTS: All 2PA specimens became loosen independently of the applied fatigue load, and structural bending was observed in 14 abutments. Eight 1PA got loosen during the fatigue experiment. The Weibull analysis showed a lower modulus (m = 1.0; 0.7, 1.4) for 1PA than for 2PA (m = 2.6; 2, 3.4) resulting in longer predicted lifetimes and slower torque degradation for 1PA than for 2PA specimens. SIGNIFICANCE: 1PA showed greater long-term survival probability than 2PA. Predicting the lifetime and mechanical behavior of implant-abutment systems are useful information to clinicians during the decision-making process of oral rehabilitations.

Structural and torque changes in implant components of different diameters subjected to mechanical fatigue.

OBJECTIVES: To evaluate torque maintenance and structural damage in implant components of different diameters subjected to a fatigue challenge. METHODS: Thirty 10-mm-long, morse taper connection, titanium dental implants and their corresponding one-piece abutments were divided into three groups (n = 10) according to implant diameter: 4.3 mm (I4.3), 3.5 mm (I3.5), and 2.9 mm (I2.9). The implants were placed into a load-bearing fixture simulating bone tissue (modified G10), and the abutments were screwed into the implants to a final torque of 20 Ncm for the I4.3 and I3.5 and 15 Ncm for I2.9. The torque was secured by a digital torque meter. Cone-beam computed tomography (CBCT) scans were acquired and post-processed (e-Vol DX software) for all implant/abutment sets before and after subjecting them to fatigue in 37 °C distilled water (2 million cycles, constant load and frequency). The removal torque was measured using the same digital torque meter to calculate the difference in torque before and after fatigue. RESULTS: I2.9 showed substantial structural deformation compared with the other implant diameters (I3.5 and I4.3). However, the experimental groups did not show statistical differences for abutment loosening. SIGNIFICANCE: Implants smaller than 3.5 mm in diameter have a higher probability of structural deformation than standard-diameter implants. The association between tomographic scans and e-Vol DX software showed satisfactory consistency with the direct assessment using the digital torque meter, offering an additional tool to evaluate implant component loosening and structural deformations.

CBCT assessment of bone thickness in maxillary and mandibular teeth: an anatomic study.

OBJECTIVE: The site of the sinus tract depends on the rate of resistance against abscess exudate drainage, bone morphology, and distance from the root apex to the outer cortical bone. To assess apical bone thickness in buccal and palatal/lingual aspects of maxillary and mandibular teeth, using a high-resolution cone-beam computed tomography (CBCT) system. METHODOLOGY: In total, 422 CBCT examinations were included in the study, resulting in a sample of 1400 teeth. The scans were acquired by PreXion 3D, with a high-resolution protocol. The bone thickness was taken as the distance between the center of the apical foramen and the buccal and lingual/palatal cortical bone. The quantitative variables were expressed as mean values±standard deviation. The independent samples were analyzed using the t-test or the Mann-Whitney test (p<0.05). RESULTS: The lowest mean value of bone thickness was observed in the buccal cortical bone of the upper canines (1.49 mm±0.86) and in the upper central incisors (1.59 mm±0.67). In premolar teeth, the lowest values were found in the buccal cortical bone of upper first premolars (1.13 mm±0.68). In the posterior teeth, the lowest values were found in the buccal cortical bone of upper first molars (1.98 mm±1.33). In the lower second molar region, the buccal cortical bone (8.36 mm±1.84) was thicker than the lingual cortical bone (2.95 mm±1.16) (p<0.05). CONCLUSIONS: The lowest mean values of bone thickness are in the buccal cortical bone of the maxillary teeth. In the mandible, bone thickness is thinner in the buccal bone around the anterior and premolar teeth, and in the lingual aspect of mandibular molars. All these anatomic characteristics could make the occurrence of the sinus tract more susceptible in these specific regions of the maxillary and mandibular alveolar bone.

CBCT assessment of bone thickness in maxillary and mandibular teeth: an anatomic study

Abstract The site of the sinus tract depends on the rate of resistance against abscess exudate drainage, bone morphology, and distance from the root apex to the outer cortical bone. Objective To assess apical bone thickness in buccal and palatal/lingual aspects of maxillary and mandibular teeth, using a high-resolution cone-beam computed tomography (CBCT) system. Methodology In total, 422 CBCT examinations were included in the study, resulting in a sample of 1400 teeth. The scans were acquired by PreXion 3D, with a high-resolution protocol. The bone thickness was taken as the distance between the center of the apical foramen and the buccal and lingual/palatal cortical bone. The quantitative variables were expressed as mean values±standard deviation. The independent samples were analyzed using the t-test or the Mann-Whitney test (p<0.05). Results The lowest mean value of bone thickness was observed in the buccal cortical bone of the upper canines (1.49 mm±0.86) and in the upper central incisors (1.59 mm±0.67). In premolar teeth, the lowest values were found in the buccal cortical bone of upper first premolars (1.13 mm±0.68). In the posterior teeth, the lowest values were found in the buccal cortical bone of upper first molars (1.98 mm±1.33). In the lower second molar region, the buccal cortical bone (8.36 mm±1.84) was thicker than the lingual cortical bone (2.95 mm±1.16) (p<0.05). Conclusions The lowest mean values of bone thickness are in the buccal cortical bone of the maxillary teeth. In the mandible, bone thickness is thinner in the buccal bone around the anterior and premolar teeth, and in the lingual aspect of mandibular molars. All these anatomic characteristics could make the occurrence of the sinus tract more susceptible in these specific regions of the maxillary and mandibular alveolar bone.

Apical Foramen Position in Relation to Proximal Root Surfaces of Human Permanent Teeth Determined by Using a New Cone-beam Computed Tomographic Software.

INTRODUCTION: The purpose of this study was to determine the position of the apical foramen (AF) in relation to root surfaces of human permanent teeth using cone-beam computed tomographic (CBCT) imaging and novel advanced imaging analysis software (e-Vol DX; CDT Software, Bauru, SP, Brazil). METHODS: The AF position was determined on CBCT scans viewed and analyzed using e-Vol DX of 1400 teeth (422 patients) according to the root surface as follows: buccal, mesiobuccal, mesial, mesiolingual/palatal, lingual/palatal, distolingual/palatal, distal, distobuccal, and central. Categoric variables were described as frequencies and percentages. Frequencies were reported with their confidence intervals (95%). Categoric variables were analyzed using the chi-square test with Yates correction. The level of significance was set at α = 0.05. RESULTS: The most frequent AF position in maxillary anterior teeth was central (46%-60%). The AF in mandibular central incisors was buccal in 44% of the cases. In maxillary first and second premolars, 39.98% and 42.56% of all AFs were central. In maxillary first and second molars, 46.12% and 57.49% of all AFs were central. The most frequent AF position in mandibular first and second premolars was central (42.85% and 50.98%). In mandibular first molars, 48.72% of all AFs were central. CONCLUSIONS: The AF position in human permanent teeth was central in 48.95% and 42.08% of the maxillary and mandibular teeth. CBCT images analyzed by e-Vol DX can be used to determine the true anatomic position of the AF and can be a useful tool for the treatment planning of nonsurgical and surgical endodontic treatments.

Large Reactional Osteogenesis in Maxillary Sinus Associated with Secondary Root Canal Infection Detected Using Cone-beam Computed Tomography.

Inflammatory injuries in the maxillary sinus may originate from root canal infections and lead to bone resorption or regeneration. This report describes the radiographic findings of 4 asymptomatic clinical cases of large reactional osteogenesis in the maxillary sinus (MS) associated with secondary root canal infection detected using cone-beam computed tomographic (CBCT) imaging. Apical periodontitis, a consequence of root canal infection, may lead to a periosteal reaction in the MS and osteogenesis seen as a radiopaque structure on imaging scans. The use of a map-reading strategy for the longitudinal and sequential slices of CBCT images may contribute to the definition of diagnoses and treatment plans. Root canal infections may lead to reactional osteogenesis in the MS. High-resolution CBCT images may reveal changes that go unnoticed when using conventional imaging. Findings may help define initial diagnoses and therapeutic plans, but only histopathology provides a definitive diagnosis. Surgical enucleation of the periapical lesion is recommended if nonsurgical root canal treatment fails to control apical periodontitis.

Cone-beam computed tomography as a diagnostic method for determination of gingival thickness and distance between gingival margin and bone crest.

The objective of the present study was to assess cone-beam computed tomography (CBCT) as a diagnostic method for determination of gingival thickness (GT) and distance between gingival margin and vestibular (GMBC-V) and interproximal bone crests (GMBC-I). GT and GMBC-V were measured in 348 teeth and GMBC-I was measured in 377 tooth regions of 29 patients with gummy smile. GT was assessed using transgingival probing (TP), ultrasound (US), and CBCT, whereas GMBC-V and GMBC-I were assessed by transsurgical clinical evaluation (TCE) and CBCT. Statistical analyses used independent t-test, Pearson's correlation coefficient, and simple linear regression. Difference was observed for GT: between TP, CBCT, and US considering all teeth; between TP and CBCT and between TP and US in incisors and canines; between TP and US in premolars and first molars. TP presented the highest means for GT. Positive correlation and linear regression were observed between TP and CBCT, TP and US, and CBCT and US. Difference was observed for GMBC-V and GMBC-I using TCE and CBCT, considering all teeth. Correlation and linear regression results were significant for GMBC-V and GMBC-I in incisors, canines, and premolars. CBCT is an effective diagnostic method to visualize and measure GT, GMBC-V, and GMBC-I.

The use of three-dimensional cephalometric references in dentoskeletal symmetry diagnosis

OBJECTIVE: The aim of this study is to assess dentoskeletal symmetry in cone-beam computed tomography (CBCT) scans of Brazilian individuals with Angle Class I malocclusion. MATERIAL: A total of 47 patients (22 females and 25 males) aged between 11 and 16 years old (14 years) seen in a private radiology service (CIRO, Goiânia, GO, Brazil) were assessed. All CBCT scans were obtained from January, 2009 to December, 2010. Cephalometric measurements were taken by multiplanar reconstruction (axial, coronal and sagittal) using Vista Dent3DPro 2.0 (Dentsply GAC, New York, USA). Minimum, maximum, mean and standard deviation values were arranged in tables, and Student t-test was used to determine statistical significance (P < 0.05). RESULTS: Data were homogeneous, and differences between the right and left sides were not significant. CONCLUSIONS: Cephalometric measurements of Brazilian individuals with Angle Class I malocclusion can be used to establish facial symmetry and three-dimensional standard references which might be useful for orthodontic and surgical planning. .

OBJETIVO: o objetivo deste estudo é avaliar a simetria dentoesqueléticas em imagens de tomografia computadorizada de feixe cônico (TCFC) de indivíduos brasileiros com má oclusão Classe I de Angle. MÉTODOS: quarenta e sete pacientes (22 meninas e 25 meninos), com idades entre 11 e 16 anos (14 anos, em média), foram atendidos em um serviço de radiologia privado. Todas as imagens de TCFC foram adquiridas a partir de janeiro de 2009 a dezembro de 2010. Medições cefalométricas foram realizadas por reconstruções multiplanares (axial, coronal e sagital) usando o VistaDent 3D Pro 2.0 ( Dentsply GAC, Nova Iorque, EUA). O desvio-padrão mínimo, máximo e a média foram descritos em tabelas, e o teste t de Student foi utilizado para definir significância estatística (p < 0,05). RESULTADOS: os dados foram homogêneos e as diferenças entre os lados direito e esquerdo não foram significativas. CONCLUSÕES: as medidas cefalométricas de indivíduos brasileiros com má oclusão Classe I de Angle podem ser usadas para definir a simetria facial e referências de padrão tridimensional, que podem ser úteis para o planejamento ortodôntico e cirúrgico. .

The use of three-dimensional cephalometric references in dentoskeletal symmetry diagnosis.

OBJECTIVE: The aim of this study is to assess dentoskeletal symmetry in cone-beam computed tomography (CBCT) scans of Brazilian individuals with Angle Class I malocclusion. MATERIAL: A total of 47 patients (22 females and 25 males) aged between 11 and 16 years old (14 years) seen in a private radiology service (CIRO, Goiânia, GO, Brazil) were assessed. All CBCT scans were obtained from January, 2009 to December, 2010. Cephalometric measurements were taken by multiplanar reconstruction (axial, coronal and sagittal) using Vista Dent3DPro 2.0 (Dentsply GAC, New York, USA). Minimum, maximum, mean and standard deviation values were arranged in tables, and Student t-test was used to determine statistical significance (P < 0.05). RESULTS: Data were homogeneous, and differences between the right and left sides were not significant. CONCLUSIONS: Cephalometric measurements of Brazilian individuals with Angle Class I malocclusion can be used to establish facial symmetry and three-dimensional standard references which might be useful for orthodontic and surgical planning.

Detection of Root Canal Isthmuses in Molars by Map-Reading Dynamic using CBCT images

The aim of this study was to detect root isthmuses in maxillary and mandibular molars and evaluate their frequencies using map-reading dynamics in CBCT images. Two hundred extracted human maxillary and mandibular molars were used in ex vivo assay. A consecutive sample of two hundred maxillary and mandibular molars (first and second) was selected from CBCT exams. The isthmuses were detected from the pulp orifice to the apex and were recorded according to their beginning and their end, into categories: 1. begin and end in cervical third; 2. beginning in cervical third and end in middle third; 3. beginning in cervical third and end in apical third; 4. beginning and end in middle third; 5. begin in middle third and end in apical third; 6. beginning and end in apical third; 7. no isthmus. The scans were obtained in different planes with map-reading in axial slices of 0.5 mm/0.5 mm involved the coronal to apical direction. The frequencies of isthmus were analyzed according to the level of root and evaluated by Chi-square test. The level of significance was set at α=0.05. The presence of isthmus detected in maxillary molars was 86% in ex vivo assay and 62% in vivo assay, whereas in mandibular molars was observed 70% in ex vivo assay and 72% in vivo assay. The frequency of isthmus was high in both study models. The map-reading dynamics in CBCT images was found to be precise to detect the localization of isthmus.

O objetivo deste estudo foi detectar a presença de istmos em molares superiores e inferiores, e avaliar a frequência usando dinâmica de navegação em imagens de tomografia computadorizada de feixe cônico (TCFC). Duzentos molares superiores e inferiores humanos foram usados em ensaio ex vivo. Uma amostra consecutiva de duzentos molares (superiores e inferiores, primeiros e segundos) foi selecionada a partir de exames de TCFC. Os istmos foram detectados a partir do orifício de entrada da cavidade pulpar em direção ao ápice, de acordo com o início e o fim, nas categorias: 1. início e término no terço cervical; 2. início no terço cervical e término no terço médio; 3. início no terço cervical e término no terço apical; 4. início e fim no terço médio; 5. início no terço médio e término no terço apical; 6. início e término no terço apical ; 7. ausência de istmo radicular. Os exames de TCFC foram obtidos em diferentes planos com estratégias de navegação em cortes axiais de 0,5 mm/0.5 mm de coronal para a direção apical. As frequências de istmo radicular foram analisadas de acordo com o terço da raiz e avaliadas pelo teste do qui-quadrado. O nível de significância estabelecido foi de 5%. A presença de istmo radicular em molares superiores foi de 86% em ensaio ex vivo e 62% em ensaio in vivo, enquanto que, em molares inferiores foram observados 70% em ensaio ex vivo e 72% em ensaio vivo. A frequência radicular de istmo foi elevada em ambos os modelos de estudo. A dinâmica da estratégia de navegação em imagens de TCFC é precisa para detectar a localização do istmo radicular.

Detection of root canal isthmuses in molars by map-reading dynamic using CBCT images.

The aim of this study was to detect root isthmuses in maxillary and mandibular molars and evaluate their frequencies using map-reading dynamics in CBCT images. Two hundred extracted human maxillary and mandibular molars were used in ex vivo assay. A consecutive sample of two hundred maxillary and mandibular molars (first and second) was selected from CBCT exams. The isthmuses were detected from the pulp orifice to the apex and were recorded according to their beginning and their end, into categories: 1. begin and end in cervical third; 2. beginning in cervical third and end in middle third; 3. beginning in cervical third and end in apical third; 4. beginning and end in middle third; 5. begin in middle third and end in apical third; 6. beginning and end in apical third; 7. no isthmus. The scans were obtained in different planes with map-reading in axial slices of 0.5 mm/0.5 mm involved the coronal to apical direction. The frequencies of isthmus were analyzed according to the level of root and evaluated by Chi-square test. The level of significance was set at α=0.05. The presence of isthmus detected in maxillary molars was 86% in ex vivo assay and 62% in vivo assay, whereas in mandibular molars was observed 70% in ex vivo assay and 72% in vivo assay. The frequency of isthmus was high in both study models. The map-reading dynamics in CBCT images was found to be precise to detect the localization of isthmus.

Effect of root canal filling materials on dimensions of cone-beam computed tomography images.

OBJECTIVE: To evaluate the discrepancy of root canal filling (RCF) measurements obtained from original root specimens and cone-beam computed tomography (CBCT) images. MATERIAL AND METHODS: Seventy-two human maxillary anterior teeth were prepared up to an ISO #50 K-File 1 mm short of the apical foramen. Thus, the teeth were randomly divided into 8 groups, according to the root canal filling material: Sealapex®, Sealapex®+gutta-percha points, Sealer 26®, Sealer 26®+gutta-percha points, AH PlusTM, AH PlusTM+gutta-percha points, Grossman Sealer, and Grossman Sealer+gutta-percha points. After root canal preparation and RCF, CBCT scans were acquired and the specimens were sectioned in axial, sagittal and coronal planes. The RCF measurements were obtained in different planes and thicknesses to determine the discrepancy between the original root specimens (using a digital caliper) and the CBCT images (using the scanner's proprietary software). One-way analysis of variance and Tukey tests were used for statistical analyses. The significance level was set at α=5%. RESULTS: Measurements of the different endodontic filling materials were 9% to 100% greater on the CBCT images than on the original root specimens. Greater RCF dimensions were found when only sealers were used, with statistically significant difference among the groups. CONCLUSIONS: RCF dimensions were greater on CBCT images than on the original root specimens, especially when only sealer was used.

Alteração da altura papilar interincisiva devido a movimentação ortodôntica: avaliação em modelos de estudo e imagens tridimensionais / Change of incisive papilla height due to orthodontic movement: an evaluation in study models and three-dimensional images

The presence of gingival papillae in the anterior maxilla is essential to the aesthetics of the smile. The aim of this study was to evaluate alterations in the height of the upper central incisive papilla, before and after orthodontic movement, using study casts and cone beam computed tomography (CBCT). Sixteen patients between the ages of 13 and 18 years underwent orthodontic treatment. The height of the papillae was calculated in both initial and final study casts by drawing a horizontal line tangent to the zenith of the central incisors and inscribing a vertical line perpendicular to the horizontal line. Papilla height was defi ned as the distance from the tip of the papilla to the point of intersection between the two lines. Initial and final (after orthodontic treatment) CBCT images were analyzed, and the height of interproximal papillae was calculated by measuring the distance from the tip of the papilla to the alveolar bone crest. This measurement was performed in both sagittal and coronal plane views. Data were statistically analyzed using the Student t test. The level of significance was 5%. Initial mean papilla height was 4.6 ± 0.8 mm, and the final value in study casts was 4.3 ± 1.2 mm; there was not a statistically significant difference between initial and final values (p = 0.309). In the CBCT coronal sections, initial mean papilla height was 3.5 ± 1.2 mm vs. 3.1 ± 0.7 mm after treatment (p = 0.094); again, no statistically significant differences were observed. In the sagittal plane, there was a significant difference (p = 0.05) between initial (3.7 ± 1.1 mm) and final (3.1 ± 0.6 mm) mean papilla height. According to our findings, and to the different measuring techniques employed, the height of the papilla changed little as a result of orthodontic therapy.

A presença de papila gengival na região anterior da maxila é essencial para a estética do sorriso. O objetivo deste estudo foi avaliar as alterações na altura papilar dos incisivos centrais superiores, antes e após movimentação ortodôntica, utilizando modelos de estudo e tomografia computadorizada de feixe cônico (TCFC). Dezesseis pacientes, com idades entre 13 e 18 anos, foram submetidos a tratamento ortodôntico. A altura da papila foi calculada nos modelos de estudo iniciais e finais. Para isso, uma linha horizontal foi traçada tangente ao zênite dos incisivos centrais e uma linha vertical foi inscrita perpendicularmente à linha horizontal. A altura papilar foi definida como a distância entre a ponta da papila até o ponto de intersecção entre as duas linhas . Nas imagens TCFC inicial e final de cada paciente, a altura da papila foi caldulada com base na distância do ponto de contato interproximal até a crista do osso alveolar. Esta medida foi realizada em cortes sagitais e coronais. Os dados foram analisados estatisticamente utilizando teste t de Student. O nível de significância foi de 5%. A altura média inicial papilar foi de 4,6± 0,8 mm, e a final, de 4,3 ± 1,2 mm; não houve diferença estatisticamente significativa entre as medidas (p = 0,309). No corte coronal da TCFC, a altura média inicial papilar foi de 3,5 ± 1,2 mm, e a final, de 3,1 ± 0,7 mm final (p = 0,094); novamente, não houve diferença estatisticamente significativa. No corte sagital, houve uma diferença significativa (p = 0,05) entre as alturas inicial (3,7 ± 1,1 mm) e final (3,1 ± 0,6 mm) média papilar. De acordo com nossos resultados e com os diferentes métodos de medição empregados, a altura da papila sofreu pouca alteração após terapia ortodôntica.

Effect of root canal filling materials on dimensions of cone-beam computed tomography images

OBJECTIVE:To evaluate the discrepancy of root canal filling (RCF) measurements obtained from original root specimens and cone-beam computed tomography (CBCT) images. MATERIAL AND METHODS: Seventy-two human maxillary anterior teeth were prepared up to an ISO #50 K-File 1 mm short of the apical foramen. Thus, the teeth were randomly divided into 8 groups, according to the root canal filling material: Sealapex ®, Sealapex®+gutta-percha points, Sealer 26®, Sealer 26®+gutta-percha points, AH PlusTM, AH PlusTM+gutta-percha points, Grossman Sealer, and Grossman Sealer+gutta-percha points. After root canal preparation and RCF, CBCT scans were acquired and the specimens were sectioned in axial, sagittal and coronal planes. The RCF measurements were obtained in different planes and thicknesses to determine the discrepancy between the original root specimens (using a digital caliper) and the CBCT images (using the scanner’s proprietary software). One-way analysis of variance and Tukey tests were used for statistical analyses. The significance level was set at α=5%. RESULTS: Measurements of the different endodontic filling materials were 9% to 100% greater on the CBCT images than on the original root specimens. Greater RCF dimensions were found when only sealers were used, with statistically significant difference among the groups. CONCLUSIONS: RCF dimensions were greater on CBCT images than on the original root specimens, especially when only sealer was used.

Efeito de retentores intrarradiculares na dimensão das imagens da tomografia computadorizada de feixe cônico

Objetivo: este estudo avaliou o efeito causado pelos constituintes dos retentores intrarradiculares sobre as dimensões das imagens de tomografia computadorizada de feixe cônico (TCFC) em dentes tratados endodonticamente. Métodos:quarenta e cinco dentes humanos anteriores superiores foram divididos em 5 grupos, de acordo com os tipos de pinos: fibra de vidro, fibra de carbono, metálicos pré-fabricados,liga de prata e pinos de liga de ouro. Os canais radiculares foram preparados, obturados, desobturados parcialmente e preparados para os retentores intrarradiculares.O material de cimentação utilizado foi um cimento resinoso(RelyX Unicem®). Exames tomográficos foram obtidos, e os espécimes seccionados nos planos axial, sagital e coronal.As medidas das dimensões dos retentores intrarradiculares foram adquiridas em diferentes planos para a determinação das diferenças entre as medidas originais dos retentores intrarradiculares e as medidas das imagens da TCFC. Análise de variância “one-way”, testes de Tukey e Kruskall-Wallisforam utilizados para análises estatísticas. O nível de significância foi estabelecido em α = 5%. Resultados: as medidas das imagens na TCFC foram maiores que nos espécimes de 7,7% a 100%. Os retentores intrarradiculares de liga de ouro e prata mostraram maiores variações (p>0,05) emrelação aos de fibra de vidro, fibra de carbono e pré-fabricados(p<0,05). Conclusões: as dimensões nas imagens da TCFC dos retentores de ouro e prata foram maiores quenos espécimes originais

Effect of intracanal posts on dimensions of cone beam computed tomography images of endodontically treated teeth

Objectives: This study evaluated the effect caused by intracanalposts (ICP) on the dimensions of cone beam computedtomography (CBCT) images of endodontically treatedteeth. Methods: Forty-five human maxillary anteriorteeth were divided into 5 groups: Glass-Fiber Post®, CarbonFiber Root Canal®, Pre-fabricated Post – Metal Screws®,Silver Alloy Post® and Gold Alloy Post®. The root canalswere prepared and filled; after that, the gutta-percha fillingwas removed, and the ICP space was prepared. The postcementation material was resin cement. CBCT scans wereacquired, and the specimens were sectioned in axial, sagittaland coronal planes. The measures of ICP were obtainedusing different 3D planes and thicknesses to determine thediscrepancy between the original ICP measurements andthe CBCT scan measurements. Results: One-way analysisof variance, Tukey and Kruskall-Wallis tests were usedfor statistical analyses. The significance level was set atα = 5%. CBCT scan ICP measurements were from 7.7%to 100% different from corresponding actual dimensions.Conclusion: Gold alloy and silver alloy posts had greatervariations (p>0.05) than glass fiber, carbon fiber and metalposts (p<0.05). Gold alloy and silver alloy post dimensionswere greater on CBCT scans than on original specimens.

Medidas lineares dos estágios de desenvolvimento da dentição permanente humana usando Tomografia Computadorizada de Feixe Cônico: um estudo preliminar / Linear measurements of human permanent dental development stages using Cone-Beam Computed Tomography: A preliminary study

OBJETIVO: determinar as medidas lineares dos estágios de desenvolvimento da dentição permanente humana, usando tomografia computadorizada de feixe cônico (TCFC). MÉTODOS: este estudo foi desenvolvido a partir de bancos de dados de clínicas radiológicas privadas, envolvendo 18 pacientes (13 do sexo masculino, 5 do sexo feminino, com idades variando entre 3 e 20 anos). As imagens das TCFC foram obtidas por meio do sistema i-CAT e medidas com uma função específica do programa desse mesmo sistema. Duzentos e trinta e oito dentes foram analisados, em diferentes estágios de desenvolvimento, nos planos coronal e sagital. O método foi baseado na delimitação e mensuração das distâncias entre pontos anatômicos correspondentes ao desenvolvimento das coroas e raízes dentárias. A partir dos valores obtidos, pôde-se desenvolver um modelo quantitativo para se avaliar os estágios inicial e final de desenvolvimento para todos os grupos dentários. RESULTADOS E CONCLUSÕES: as medidas obtidas dos diferentes grupos dentários estão de acordo com as estimativas das investigações publicadas previamente. As imagens por TCFC dos diferentes estágios de desenvolvimento podem contribuir no diagnóstico, planejamento e resultado dos tratamentos em diversas especialidades odontológicas. As dimensões das coroas e das raízes dentárias podem ter importantes aplicações clínicas e em pesquisas, constituindo uma técnica não invasiva que contribui com estudos in vivo. Entretanto, mais estudos são recomendados a fim de minimizar possíveis variáveis metodológicas.

OBJECTIVE: To determine the linear measurements of human permanent dentition development stages using Cone-Beam Computed Tomography. METHODS: This study was based on databases of private radiology clinics involving 18 patients (13 male and 5 female, with age ranging from 3 to 20 years). Cone-Beam Computed Tomography (CBCT) images were acquired with i-CAT system and measured with a specific function of the i-CAT software. Two hundred and thirty-eight teeth were analyzed in different development stages in the coronal and sagittal planes. The method was based on delimitation and measurement of the distance between anatomical landmarks corresponding to the development of the dental crowns and roots. These measurements allowed the development of a quantitative model to evaluate the initial and final development stages for all dental groups. RESULTS AND CONCLUSIONS: The measurements acquired from different dental groups are in agreement with estimates of investigations previously published. CBCT images of different development stages may contribute to diagnosis, planning and outcome of treatment in various dental specialties. The dimensions of dental crowns and roots may have important clinical and research applications, constituting a noninvasive technique which contributes to in vivo studies. However, further studies are recommended to minimize methodological variables.

Alterações dimensionais do côndilo mandibular em indivíduos de 3 a 20 anos de idade usando tomografia computadorizada de feixe cônico: um estudo preliminar / Mandibular condyle dimensional changes in subjects from 3 to 20 years of age using Cone-Beam Computed Tomography: A preliminary study

INTRODUÇÃO: o exame de tomografia computadorizada de feixe cônico (TCFC) oferece excelente representação dos tecidos duros da articulação temporomandibular (ATM). OBJETIVO: investigar as alterações morfológicas do côndilo mandibular, da infância à idade adulta, utilizando a TCFC. MÉTODOS: um estudo transversal foi conduzido envolvendo 36 côndilos de 18 indivíduos com idades variando entre 3 e 20 anos. As imagens dos côndilos foram obtidas por meio do sistema i-CAT e medidas com uma ferramenta do programa específica para ATM, que permite cortes perpendiculares à cabeça do côndilo, com correção individual em função das diferenças angulares de cada um. As maiores distâncias nas vistas lateral e frontal foram consideradas tanto para os côndilos do lado direto como para os do lado esquerdo. RESULTADOS: a dimensão lateral do côndilo mandibular parece ser estabelecida de maneira precoce, sofrendo poucas alterações com o passar dos anos, enquanto a dimensão frontal tende a aumentar. Assimetrias entre o côndilo esquerdo e o direito foram comumente observadas; no entanto, tais diferenças não apresentaram significância estatística para as vistas lateral (P=0,815) e frontal (P=0,374). CONCLUSÕES: os côndilos apresentaram simetria com relação ao tamanho, sendo observado crescimento apenas na dimensão frontal Os resultados sugerem que a TCFC constitui-se numa ferramenta útil na mensuração e avaliação das dimensões condilares.

INTRODUCTION: Cone-Beam Computed Tomography (CBCT) imaging provides an excellent representation of the temporomandibular joint bone tissues. OBJECTIVE: The aim of this study was to investigate morphological changes of the mandibular condyle from childhood to adulthood using CBCT. METHODS: A cross-sectional study was conducted in 36 condyles of 18 subjects from 3 to 20 years of age. Condyles were scanned with the i-CAT Cone-Beam 3D imaging system and linear dimensions were measured with a specific i-CAT software function for temporomandibular joint, which permitted slices perpendicular to the condylar head, with individual correction in function of angular differences for each condyle. The greatest distances in lateral and frontal sections were considered on both left and right mandibular condyles. RESULTS: The linear dimension of the mandibular condyle on the lateral section varied little with growth and seemed to be established early, while the dimension of the frontal section increased. Small asymmetries between left and right condyles were common but without statistical significance for both lateral (P=0.815) and frontal (P=0.374) dimensions. CONCLUSIONS: The condyles were symmetric in size and only the frontal dimension enlarged during growth. These preliminary data suggest that CBCT is a useful tool to measure and evaluate the condylar dimensions.

Influence of intracanal post on apical periodontitis identified by cone-beam computed tomography.

The determination of the success of endodontic treatment has been often discussed based on outcome obtained by periapical radiography. The aim of this study was to verify the influence of intracanal post on apical periodontitis detected by cone-beam computed tomography (CBCT). A consecutive sample of 1020 images (periapical radiographs and CBCT scans) taken from 619 patients (245 men; mean age, 50.1 years) between February 2008 and September 2009 were used in this study. Presence and intracanal post length (short, medium and long) were associated with apical periodontitis (AP). Chi-square test was used for statistical analyses. Significance level was set at p<0.01. The kappa value was used to assess examiner variability. From a total of 591 intracanal posts, AP was observed in 15.06%, 18.78% and 7.95% using periapical radiographs, into the different lengths, short, medium and long, respectively (p=0.466). Considering the same posts length it was verified AP in 24.20%, 26.40% and 11.84% observed by CBCT scans, respectively (p=0.154). From a total of 1,020 teeth used in this study, AP was detected in 397 (38.92%) by periapical radiography and in 614 (60.19%) by CBCT scans (p<0.001). The distribution of intracanal posts in different dental groups showed higher prevalence in maxillary anterior teeth (54.79%). Intracanal posts lengths did not influenced AP. AP was detected more frequently when CBCT method was used.

Influence of intracanal post on apical periodontitis identified by cone-beam computed tomography

The determination of the success of endodontic treatment has been often discussed based on outcome obtained by periapical radiography. The aim of this study was to verify the influence of intracanal post on apical periodontitis detected by cone-beam computed tomography (CBCT). A consecutive sample of 1020 images (periapical radiographs and CBCT scans) taken from 619 patients (245 men; mean age, 50.1 years) between February 2008 and September 2009 were used in this study. Presence and intracanal post length (short, medium and long) were associated with apical periodontitis (AP). Chi-square test was used for statistical analyses. Significance level was set at p<0.01. The kappa value was used to assess examiner variability. From a total of 591 intracanal posts, AP was observed in 15.06 percent, 18.78 percent and 7.95 percent using periapical radiographs, into the different lengths, short, medium and long, respectively (p=0.466). Considering the same posts length it was verified AP in 24.20 percent, 26.40 percent and 11.84 percent observed by CBCT scans, respectively (p=0.154). From a total of 1,020 teeth used in this study, AP was detected in 397 (38.92 percent) by periapical radiography and in 614 (60.19 percent) by CBCT scans (p<0.001). The distribution of intracanal posts in different dental groups showed higher prevalence in maxillary anterior teeth (54.79 percent). Intracanal posts lengths did not influenced AP. AP was detected more frequently when CBCT method was used.

O objetivo deste estudo foi determinar a influência de retentores intraradiculares na periodontite apical (PA), detectados por radiografia periapical (RP) e tomografia computadorizada de feixe cônico (TCFC). Um total de 1.020 imagens, tomadas de 619 pacientes (245 homens, idade média de 50,1 anos), entre Fevereiro de 2008 e Setembro de 2009, foram avaliadas. A presença e o comprimento de retentores intraradiculares (curto, médio e longo) foram associados com a PA. Os dados foram estatisticamente avaliados empregando-se os testes Qui-quadrado e o Kappa. Três observadores avaliaram todas as imagens, considerando-se a presença de retentor intraradicular, seu comprimento e a PA. De um total de 1.020 dentes analisados no estudo, a PA foi detectada em 397 (38,92 por cento) usando RP e em 614 (60,19 por cento) usando TCFC (p<0,001). Em 591 retentores intraradiculares, nos diferentes comprimentos (curto, médio, longo) foram observadas PA usando RP em 15,06 por cento; 18,78 por cento e 7,95 por cento, respectivamente (p=0,466). Considerando os mesmos comprimentos de retentores foram observados PA em 24,20 por cento; 26,40 por cento e 11,84 por cento por meio de TCFC, respectivamente (p=0,154). A distribuição de retentores nos diferentes grupos dentários mostrou elevada prevalência em dentes anteriores superiores (54,79 por cento). Os retentores intraradiculares não influenciaram a PA e as TCFC detectaram mais freqüentemente a periodontite apical.