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.

Rare case of gemination and fusion involving supernumerary teeth and second mandibular molar - Case report.

This article presents the rare case of a patient with gemination and fusion involving conical supernumerary teeth and the second mandibular molar, along with its treatment. The 13-year-old girl, without any associated syndromes and currently undergoing orthodontic treatment, was referred for evaluation due to the presence of a supernumerary tooth. Following a clinical examination and analysis of a panoramic radiograph, a cone beam computed tomography was requested for a more detailed assessment of the supernumerary tooth and its relationship with adjacent structures. The sagittal sections revealed the presence of two conical paramolar supernumerary teeth, which were geminated and fused to the mesial root of tooth 47. The suggested treatment was the surgical removal of the supernumerary teeth, which was successfully performed without complications and with good healing. After one-year post-procedure, the formation of periodontal ligament was verified at the site where the supernumerary teeth were extracted. The simultaneous occurrence of gemination of two supernumerary teeth and their fusion to a mandibular molar is extremely rare, and their surgical removal provided the patient with better plaque control in the region and contributed to the progress of orthodontic treatment. Key words:Gemination and fusion of supernumerary teeth and second mandibular molar.

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.

Blooming artifact reduction using different cone-beam computed tomography software to analyze endodontically treated teeth with intracanal posts.

BACKGROUND: The appearance of high-density root obturating materials, such as gutta-percha and intracanal posts, on cone-beam computed tomography (CBCT) scans is substantially different from that seen in the specimen. This study evaluated the effectiveness of different CBCT software in the reduction of blooming artifacts when examining teeth with intracanal posts. METHOD: The sample included 42 human single-rooted teeth with two types of posts: G1 - low-fusion alloy posts; G2 - gold alloy posts. CBCT scans were obtained using two scanners, PreXion 3D Elite® and Carestream 9000C 3D®. First, the posts were measured using a digital micrometer (standard reference, control). Post diameters were determined using the Blooming Artifact Reduction (BAR) tool of the e-Vol DX software and of the PreXion3D Image Analysis System. Statistical data were evaluated using the van Der Waerden nonparametric analysis of variance and, after that, normalized data were analyzed using the Tukey test. The level of significance was set at α = 5 %. RESULTS: There were no significant differences (p > 0.05) between the diameters of intracanal posts on the CT scans when the e-Vol DX was used, or when these results were compared with those obtained using a micrometer. There were significant differences in post diameters determined using the PreXion3D Image Analysis System when compared with the e-Vol DX and the micrometer values (p < 0.05). CONCLUSIONS: The use of the e-Vol DX BAR filter eliminated blooming artifacts. There were no dimensional changes in the CBCT images of the low-fusion and gold alloy intracanal posts using the e-Vol DX BAR filter.

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.

Defeito osteoporótico focal nos maxilares: estudo transversal retrospectivo em 525 tomografias computadorizadas de feixe cônico / A cross-sectional retrospective study on focal osteoporotic bone marrow jaw defects: evaluation of 525 CBCT images

Objetivo: avaliar a prevalência do defeito osteoporótico focal nos maxilares (DOFMO) através de imagens radiográficas. Material e métodos: neste estudo transversal e retrospectivo, tomografias computadorizadas de feixe cônico (TCFC) – voxel = 0,2 mm, 120 KVp, 36,12 mA – foram selecionadas a partir de um banco de dados e analisadas em um programa de computador específico. O DOFMO foi definido como uma imagem hipodensa no trabeculado medular, circunscrita, sem limites muito definidos e sem envolvimento cortical, ausência de expansão, sem aspectos de lesão cística e nenhum envolvimento odontogênico, delimitado por linhas hiperdensas finas e contínuas separadas do trabeculado ósseo vizinho. Dois examinadores calibrados foram constituídos, e as discordâncias foram resolvidas por um terceiro avaliador. Resultados: o número total de TCFCs investigadas foi 525 (maxila = 258, mandíbula = 267), sendo 195 homens e 330 mulheres, com média de idade de 50,7 anos. Foram observados 91 DOFMOs (17,3%), sendo 32 (61,5%) no sexo feminino e 21 (38,4%) no sexo masculino. Em 44 casos (83,1%), observou-se o defeito na mandíbula; em nove casos (6,9%), observou-se o defeito na maxila. Em 38 casos (71,7%), o DOFMO se deu bilateralmente; em 15 casos (28,3%), foi observada distribuição unilateral, sendo que 12 foram encontrados na mandíbula e três na maxila. Conclusão: através deste estudo, pôde-se concluir que o DOFMO não se apresentou incomum e deve ser considerado durante o planejamento cirúrgico de instalação de implantes dentários.

Objective: to evaluate the prevalence of osteoporotic focal defect in the jaw (OFDJ) through radiographic images. Material and methods: in the cross-sectional retrospective study, CBCTs (voxel = 0.2 mm, 120 KVp, 36.12 mA) were selected from a databank and analyzed with a specifi c computer program. OFDJ was defined as circumscribed, hypodense image at the marrow area without defined limits without cortical involvement, no expansion, no aspects of cystic lesion and no odontogenic involvement, bounded by thin and continuous hyperdense lines separated from the adjacent trabecular bone. Two calibrated examiners made the diagnosis; disagreements were arbitrated by a third reviewer. Results: 525 CBCTs were investigated (maxilla = 258; mandible = 267), being 195 men and 330 women (mean age of 50.7 years). 91 OFDJ cases (17.3%) were seen, being 32 (61.5%) female and 21 (38.4%) and male. In 44 cases (83.1%) there was a mandibular defect, whereas 9 cases (6.9%) were seen in the maxillary arch. Bilateral distributions were seen for 38 cases (71.7%), while the unilateral pattern was observed only for 15 cases (28.3%), being these 12 in the mandible and 3 in the maxilla. Conclusion: OFDJ is not uncommon and must be considered during the planning for dental implant placement.

Fifteen-year follow-up of a conservatively managed, root-fractured permanent incisor.

The purpose of this case report was to describe the successful long-term conservative management of a root-fractured permanent maxillary right central incisor in an 8-year-old patient. After the initial approach of splinting the traumatized tooth, the patient was followed on a regular basis for 15 years. Clinically, the crown of the root-fractured incisor showed no displacement or discoloration, and thermal tests suggested pulp vitality over the follow-up period. Radiographically, an increase in the diastasis was observed between the apical and coronal fragments due to both the growth of the alveolar process and the healing with interposition of hard and soft tissue between the fragments and confirmed with computed tomography scan in the 15-year follow-up appointment.

Tomografia computadorizada Cone Beam: revolução na Odontologia / Cone-beam computed tomography: revolution of Dentistry

Uma das descobertas responsáveis pela revolução mundial é a informática. A aplicação dos benefícios nos distintos setores da saúde permitiu expressivo auxílio no diagnóstico, na terapêutica, na ciência, economia de tempo, além de influenciar a qualidade de vida. A biotecnologia continua revolucionando o pensamento atual. As imagens interpretadas pelas radiografias em apenas dois planos, desde sua descoberta por Rõntgen em 1895, atravessaram quase um século. Hoje a tomografia computadorizada Cone Beam (CBCT) permite uma visualização de uma imagem tridimensional, em que um novo plano é adicionado: a profundidade. Sua aplicação clínica, com elevada acurácia, se direciona a quase todas as áreas da Odontologia - Cirurgia, Implantodontia, Ortodontia, Endodontia, Periodontia, Distúrbio Temporomandibular e Diagnóstico por Imagens. A visão real da associação destes indicadores aos aspectos clínicos projeta a quarta dimensão, marcada pela necessidade de tempo e espaço. Assim, estudou-se a revolução da Odontologia a partir da CBCT.

One of the responsible founds for the world revolution is the informatics. The application of the benefits in different sectors of health allowed expressive aid of diagnosis, therapeutic, science, economy of time, besides influencing in life quality. A biotechnology continues revolutionizing the current thought. The images interpreted by the x-rays in only two plans, since their discovery for Rõntgen in 1895, they almost crossed one century. Today, the tomography computerized Cone Beam allows a visualization of a three-dimensional image, where a new plan is added, the depth. Its clinical application, with high accuracy, directed to all of the areas of the Dentistry - Surgery, Implantodontology, Orthodontics, Endodontics, Periodontology, Temporomandibular Joint (TMJ) Dysfunctions and Diagnosis for Images. The real vision of the association of these indicators to the clinical aspects, projects the fourth dimension, marked by the need of time and space. Therefore, the objective of this paper was to study the revolution of the dental practice starting from the Cone Beam computed tomography.

Análise computadorizada do sorriso em Ortodontia / Computadorized analysis of the smile in Orthodontics

A procura pelo tratamento ortodôntico está, na maioria das vezes, relacionada a motivos estéticos. Um belo sorriso é de extremo valor perante a sociedade de hoje. Estabelecer elementos de diagnóstico e planejamento, visando buscar um sorriso harmonioso e bem balanceado, tornou-se uma obrigação nos consultórios de Odontologia. A estética do sorriso baseia-se numa avaliação não apenas dos tecidos ósseos, mas também da sua relação com os tecidos tegumentares. Uma boa maneira para obter essa avaliação é fazendo uso da fotografia. Com base nesse contexto, este trabalho tem por objetivo uma análise de fotografias computadorizadas, padronizadas, do sorriso máximo, em pacientes do sexo masculino, como complemento à documentação ortodôntica, para auxiliar não somente no diagnóstico e planejamento, mas também na avaliação dos resultados obtidos. As fotografias foram produzidas na posição natural da cabeça, e sobre elas foram realizadas medidas lineares, angulares e proporcionais por meio do método computadorizado (program CEFX2001 - CDT). A amostra consistiu em 28 pacientes, do sexo masculino, com idade entre 19 e 25 anos, com oclusão de classe I, não tratados ortodonticamente. Foram obtidos os valores das estatísticas descritivas e da análise do erro. Os resultados foram comparados aos valores encontrados na literatura, assim como aos alcançados numa análise com amostras do sexo feminino, utilizando-se o mesmo programa computadorizado CEFX2001. Os resultados foram semelhantes aos valores encontrados na literatura e nas amostras do sexo feminino

In most cases the search for orthodontic treatment is related with esthetics cause. Nowadays, a beautiful smile is extremely important for the society. Establishing elements for diagnosis and planning, looking at a harmonious and well-balanced smile became an obligation at dentistry offices. The esthetics is evaluated by the outline of the bone tissues and its relation with the soft tissues. A good way to get this evaluation is using photographs. The purpose of this research was to analyze computer standard pictures of the maximum smile, as complement to the orthodontic documentation to help not only in the diagnostic and planning but also in the valuation of obtained results. Standard pictures of the maximum smile were obtained in the natural position of the head. Linear, angular and proportional measures were evaluated through the computerized program (CEFX2001 ­ CDT). The sample consisted of 28 patients, white, male, age between 19 and 25 years old, with Class I occlusion and no previous orthodontic treatment. The values of the descriptive statistics and error analysis were obtained. The results were compared with the values found in the literature, and the values found at a study using the same computerized program CEFX2001 ­ CDT, but with female patients. The final results were similar to the values found in the literature and the values found in a study using the same computerized program CEFX2001 ­ CDT, but with female patients