Assessing peri-implant bone microarchitecture: conventional vs. osseodensification drilling - ex vivo analysis.

The aim was to evaluate primary implant stability and bone microarchitecture in two drilling situations, by comparing the conventional technique (CT) and osseodensification (OD) (Versah Burs - Jackson - Mississippi - USA). The implant insertion torque (IT), implant stability quotient (ISQ), and the peri-implant trabecular microstructure were assessed on bone fragments obtained from pig's tibia (n=12), divided between CT (n=6) and OD (n=6). After the drilling procedure, the implants were installed (3.5x8.5 mm, Epikut - SIN - São Paulo - Brazil). The IT and ISQ were measured using a digital torque wrench and resonance frequency analysis. Then, the bone fragments containing the implants were removed with a trephine and analyzed by Microtomography (µCT, 8.0 µm). The comparison between groups was performed using the unpaired t-test (α=0.05). The results revealed that OD promotes a higher insertion torque (CT: 7.67±2.44 Ncm; OD: 19.78±5.26 Ncm) (p=0.0005), although ISQ was not different (CT: 61.33±4.66; OD: 63.25±4.58) (p=0.48). There was a significant increase in peri-implant bone volume (CT: 23.17±3.39 mm3; OD: 32.01±5.75 mm3) (p=0.008), and trabecular parameters: separation (CT: 0.4357±0.03 mm; OD: 0.3865±0.04 mm) (p=0.0449), number (CT: 1.626±0.18 1/mm; OD: 1.946±0.13 1/mm) (p=0.007), and thickness (CT: 0.1130±0.009 mm; OD: 0.1328±0.015 mm) (p=0.02). Structure model index (SMI) data demonstrate no significant differences between groups (CT: 1.7±0.2; OD: 1.4±0.4) (p=0.12). In conclusion, OD increases the insertion torque values and promotes beneficial changes regarding bone microarchitecture compared with CT, revealing more peri-implant bone volume with consequent higher primary stability.

Assessing peri-implant bone microarchitecture: conventional vs. osseodensification drilling - ex vivo analysis

Abstract: The aim was to evaluate primary implant stability and bone microarchitecture in two drilling situations, by comparing the conventional technique (CT) and osseodensification (OD) (Versah Burs - Jackson - Mississippi - USA). The implant insertion torque (IT), implant stability quotient (ISQ), and the peri-implant trabecular microstructure were assessed on bone fragments obtained from pig's tibia (n=12), divided between CT (n=6) and OD (n=6). After the drilling procedure, the implants were installed (3.5x8.5 mm, Epikut - SIN - São Paulo - Brazil). The IT and ISQ were measured using a digital torque wrench and resonance frequency analysis. Then, the bone fragments containing the implants were removed with a trephine and analyzed by Microtomography (µCT, 8.0 µm). The comparison between groups was performed using the unpaired t-test (α=0.05). The results revealed that OD promotes a higher insertion torque (CT: 7.67±2.44 Ncm; OD: 19.78±5.26 Ncm) (p=0.0005), although ISQ was not different (CT: 61.33±4.66; OD: 63.25±4.58) (p=0.48). There was a significant increase in peri-implant bone volume (CT: 23.17±3.39 mm3; OD: 32.01±5.75 mm3) (p=0.008), and trabecular parameters: separation (CT: 0.4357±0.03 mm; OD: 0.3865±0.04 mm) (p=0.0449), number (CT: 1.626±0.18 1/mm; OD: 1.946±0.13 1/mm) (p=0.007), and thickness (CT: 0.1130±0.009 mm; OD: 0.1328±0.015 mm) (p=0.02). Structure model index (SMI) data demonstrate no significant differences between groups (CT: 1.7±0.2; OD: 1.4±0.4) (p=0.12). In conclusion, OD increases the insertion torque values and promotes beneficial changes regarding bone microarchitecture compared with CT, revealing more peri-implant bone volume with consequent higher primary stability.

Resumo O objetivo deste estudo foi avaliar a estabilidade de implante e a microarquitetura óssea em duas técnicas de fresagem, comparando a técnica convencional (CT) e a osseodensificação (OD) (Versah Burs - Jackson - Mississippi - EUA). O torque de inserção do implante (IT), quociente de estabilidade primária (ISQ) e a estrutura trabecular peri-implantar foram avaliados em fragmentos ósseos obtidos de tíbia de porco (n=12), divididos entre CT (n=6) e OD (n=6). Após o procedimento de fresagem, foram instalados implantes (3,5x8,5 mm, Epikut - SIN - São Paulo - Brasil). O IT e o ISQ foram aferidos por meio de um torquimetro digital e análise de frequência de ressonância. Em seguida, os fragmentos ósseos contendo os implantes foram removidos com trefina e analisados ​​por microtomografia computadorizada (µCT, 8,0 µm). A comparação entre os grupos foi realizada por meio do teste-t não-pareado (α=0.05). Os resultados revelaram que a OD promove maior torque de inserção (CT: 7,67 ± 2,44º Ncm; OD: 19,78 ± 5,26 Ncm) (p=0,0005), embora a estabilidade primária não tenha sido diferente (CT: 61.33 ± 4.66; OD:63.25 ± 4.58) (p=0,48). Houve um aumento significativo no volume ósseo peri-implantar (CT: 23,17±3,39 mm3; OD: 32,01±5,75 mm3) (p=0,0089) e parâmetros trabeculares: separação (CT: 0,4357 ± 0,03 mm; OD: 0,3865 ± 0,04 mm) (p=0,0449), número (CT: 1,626 ± 0,18 1/mm; OD: 1,946 ± 0,13 1/mm) (p=0,007) e espessura (CT: 0,1130 ± 0,009 mm; OD: 0,1328 ± 0,015 mm) (p=0,02) O índice de modelo estrutural (SMI) não demostrou diferença estatisticamente significativa (p=0.1228). Concluindo, OD apresenta maiores valores de torque de inserção e promove mudanças benéficas na microarquitetura óssea em comparação com a TC, revelando maior volume ósseo peri-implantar.

Cortical microarchitecture and remodeling-associated gene expression related to oral cancer prognosis.

The objective of this study was to assess the remodeling-associated gene expression in the mandible of patients diagnosed with oral squamous cell carcinoma (OSCC), investigating the cortical microarchitecture, and their influence on disease-free survival (DFS) and overall survival (OS) rates. A total of twenty-four patients who underwent mandibulectomy for OSCC treatment had two bone fragments harvested from the mandible for gene expression (RANK, RANKL, OPG, and SOST), and microarchitecture analysis, including bone volume, surface, mineral density, degree of anisotropy, and fractal dimension. The prognosis of the patients was assessed. The results revealed that RANK, RANKL, and SOST were predominantly downregulated, while OPG was completely downregulated. Tumors located adjacent to the posterior region of the mandible (p = 0.02), with a bone mineral density below 1.03 g/cm3 HA (p = 0.001), and a bone volume less than 86.47% (p = 0.03) were associated with poor outcomes. In conclusion, bone-remodeling-associated genes exhibited downregulation in the cortex of the mandible in OSCC patients. Additionally, the tumor's location within the mandible, bone volume, and cortical bone mineral density were identified as factors impacting DFS.

Cortical microarchitecture and remodeling-associated gene expression related to oral cancer prognosis

Abstract The objective of this study was to assess the remodeling-associated gene expression in the mandible of patients diagnosed with oral squamous cell carcinoma (OSCC), investigating the cortical microarchitecture, and their influence on disease-free survival (DFS) and overall survival (OS) rates. A total of twenty-four patients who underwent mandibulectomy for OSCC treatment had two bone fragments harvested from the mandible for gene expression (RANK, RANKL, OPG, and SOST), and microarchitecture analysis, including bone volume, surface, mineral density, degree of anisotropy, and fractal dimension. The prognosis of the patients was assessed. The results revealed that RANK, RANKL, and SOST were predominantly downregulated, while OPG was completely downregulated. Tumors located adjacent to the posterior region of the mandible (p = 0.02), with a bone mineral density below 1.03 g/cm3 HA (p = 0.001), and a bone volume less than 86.47% (p = 0.03) were associated with poor outcomes. In conclusion, bone-remodeling-associated genes exhibited downregulation in the cortex of the mandible in OSCC patients. Additionally, the tumor's location within the mandible, bone volume, and cortical bone mineral density were identified as factors impacting DFS.

Artifacts caused by titanium implants in CBCT images of the mandible: an experimental study.

This study evaluated the quantity of metal artifacts produced by dental implants placed in different mandibular regions using various cone beam computed tomography (CBCT) protocols. Titanium implants were placed in 4 regions (incisor, canine, premolar, and molar) of an artificial mandible and subjected to CBCT examinations with the mandibular model placed in different positions within the field of view (FOV) and imaged with different FOV and voxel sizes. An axial section of the cervical region of each implant was selected for artifact quantification. The artifacts were measured by normalizing the actual standard deviation (ASD) of the voxel values. Kruskal-Wallis and Student-Newman-Keuls tests were used to compare the tooth regions and the different positions of the mandible. The Wilcoxon test was used to compare changes in FOV and voxel size. The intraobserver agreement was calculated using the intraclass correlation coefficient. The significance level was 5%. The incisor region showed significantly more artifacts than other regions (P = 0.0315). No statistically significant difference was found when the position of the mandible varied within the FOV (P = 0.7418). Smaller FOV and smaller voxels produced more artifacts (P < 0.0001). The quantity of metal artifacts was affected by FOV and voxel size as well as by anatomical region. Variation of the mandible location within the FOV did not affect the artifacts as defined by the normalized ASD of the voxel values.

Implant site preparation-related bone microdamage: An alternative ex vivo analysis of drilling speed protocols / Microdanos ósseos gerados na preparação do sítio de instalação de implantes: uma alternativa para análise ex vivo de diferentes protocolos de velocidade de perfuração

ABSTRACT Objective: The aim of this study was to evaluate bone microdamage in sites prepared for implant placement by using an ex vivo model with three drilling rotation speeds. Methods: Bovine bone ribs were used for the creation of 18 osteotomy sites at different rotation speeds: 1200 rpm, 800 rpm, and 400 rpm. Specimens were stained with xylenol orange and prepared for histological analysis by using fluorescence and polarized light microscopies. Bone microdamage was evaluated by number and based on total bone area, as follows: microfracture density (Fr.D = n/mm2), microcrack morphology (diffuse or linear), and density (Cr.D = n/mm2), and presence of bone chips. To complement the analysis, linear microcracks were assessed by using confocal microscopy for three-dimensional visualization. Results: Bone microdamage on the osteotomy sites included microcracks, diffuse damages, microfracture, and bone chip formation. There was an association between bone microdamage and cancellous bone (p 0.0016), as well as a positive correlation between Fr.D and Cr.D (p 0.05, r 0.54). BM occurrence was not different between the three rotation speeds. In 3D, the height of the microcrack depth was 60.81 µm. Conclusion: Bone microdamage occurs during osteotomy, and the ex vivo model used was effective for the assessment of these biomechanical parameters. In addition, microdamage was not influenced by the drilling rotation speed in this experimental condition.

RESUMO Objetivo: O objetivo desse estudo foi avaliar os microdanos ósseos em locais preparados para a instalação de implantes utilizando um modelo ex vivo acessando três velocidades de rotação de perfuração. Métodos: Fragmentos ósseos de costela bovina foram utilizados para a criação de 18 sítios de osteotomia em diferentes velocidades de rotação: 1200 rpm, 800 rpm e 400 rpm. As amostras foram coradas com Alaranjado de Xilenol e preparadas para análise microscópica em fluorescência e luz polarizada. Os microdanos ósseos foram avaliados em número e calibrados com base na área total óssea: densidade de microfraturas (Fr.D = n/mm2), morfologia (difusa ou linear) e densidade de microtrincas (Cr.D = n / mm2) e presença de espículas ósseas. Para complementar a análise, microtrincas lineares foram avaliadas por meio de microscopia confocal para visualização tridimensional. Resultados: Os microdanos ósseos incluíram microtrincas, danos difusos, microfraturas e formação de espículas. Houve uma associação entre MO e localização em osso esponjoso (p=0,0016), bem como uma correlação positiva entre Fr.D e Cr.D (p=0,05, r = 0,54). A ocorrência de microdanos ósseos não foi diferente entre as três velocidades de rotação utilizadas. Em 3D, a profundidade maior da microfissura atingiu 60,81 µm. Conclusão: Microdanos ósseos ocorrem durante a osteotomia e podem ser acessados em um modelo ex vivo na condução de experimentos em biomecânica. Sugere-se que a presença de microdanos não é influenciada pela velocidade de rotação durante a perfuração.

Immediate three-dimensional changes in the oropharynx after different mandibular advancements in counterclockwise rotation orthognathic planning.

BACKGROUND: A retrospective cohort study was performed to evaluate the immediate effect on the oropharynx dimensions from different mandibular advancements in patients undergone counterclockwise rotation (CCW) of the maxillomandibular complex. MATERIAL AND METHODS: 138 CBCT images of patients, who had undergone orthognathic surgery, were identified from Dolphin Imaging archive according to pre- (T0) and post-operative (T1) times. Each pre-operative CBCT image was selected considering retrognathic mandible. Superimpositions of CBCT images were performed to measure mandibular advancement at B point in millimeters (mm) and divided into three groups: G1 (< 5 mm), G2 (between 5 and 10 mm) and G3 (> 10 mm). For evaluating oropharynx dimension at T0 and T1 for each group, medial sagittal area (MSA), volume, and minimum cross-sectional axial area (CSA) were measured on Dolphin Imaging. Pearson correlation verified reliability of method. Paired t-test were applied to compare values of measurements between T0 and T1 (p ≤ 0.05). RESULTS: 88 CBCT images were included. Method was reliable (r ≥ 0.93). According to MSA, volume and CSA values from G1, there was no significant difference between T0 and T1. CSA values presented significant difference comparing T0 and T1 in G2 (p ≤ 0.05). In subjects of G3, measurements increased in T1 significantly affecting oropharynx dimension. CONCLUSIONS: MSA, volume and CSA values showed a significant increase affecting upper airway in advancements higher than 10 mm. Mandibular advancement range showed different effects in the airway space and should be considered to achieve favorable post-operative results in the oropharynx dimensions. Key words:Retrognathia, orthognathic surgery, three-dimensional imaging, oropharynx, airway.

Panoramic versus CBCT used to reduce inferior alveolar nerve paresthesia after third molar extractions: a systematic review and meta-analysis.

OBJECTIVES: The aim of this systematic review was to verify whether CBCT in comparison with panoramic radiography reduced the cases of temporary paresthesias of the inferior alveolar nerve (IAN) associated with third molar extractions. METHODS: The literature search included five databases (PubMed, Scopus, Web of Science, Cochrane, SciELO), in addition to gray literature and hand search of reference list of included studies. Two reviewers independently screened titles/abstracts, and full texts according to eligibility criteria, extracted data and evaluated risk of bias through Revised Cochrane Risk of Bias Tool for Randomized Trials (RoB 2.0). Data were meta-analyzed by comparing CBCT versus panoramic radiographs for number of events (temporary paresthesia after third molar surgery). Fixed effect model was used for non-significant heterogeneity; relative risk (RR) and 95% CI were calculated. The certainty of evidence was evaluated by Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). RESULTS: Four randomized controlled trials (RCTs) were included in meta-analysis, and for the majority of domains they presented low risk of bias. RR was 1.23 (95% IC: 0.75-2.02; I2: 0%; p = 0.43) favouring panoramic radiography, but without significant effect, and with moderate certainty of evidence. CONCLUSIONS: We concluded that both interventions had a similar ability to reduce temporary paresthesia of the IAN after third molar surgery with moderate certainty of evidence.

Medical emergencies teaching in dentistry undergraduate courses in Southeastern Brazil

Aim: The aim of this study is to offer an overview of the MedicalEmergencies (ME) discipline offer in Dentistry graduations insoutheastern Brazil and to observe the curricular characteristicsof the discipline when present. Methods: This cross-sectionaldocumentary study analyzed the available curricular frameworksin the official websites of Higher Education Institutions (HEI)in southeastern Brazil registered on the Ministry of Education'se-MEC website. The data were analyzed and tabulated using theGraphPad Prism 8.1.2 software, being described by absolute andrelative frequencies. Fisher's exact test was used to compare theproportions between public and private institutions. Results:Of the 176 courses in the Southeast, 144 were included in thestudy for providing access to the curriculum, 19 (13.19%) werepublic and 125 (86.81%) were private. Only 27 (18.75%) of the HEIpresent the discipline of ME, with a greater tendency of supply inprivate HEIs (20.80%) when compared to public HEIs (5.26%),but this difference was not statistically significant (p> 0.05).As a positive aspect, the discipline is predominantly mandatory(88.88%), and the with regard to the teaching methodology ispredominantly theoretical (68.18%). The average workload is50.14 hours (SD=19.54). Conclusions: In only 18.75% of thedental institutions in Southeast Brazil, ME discipline were offered.When offered, the discipline is predominantly theoretical andmandatory. This study raises an important discussion regardingthe need to include specific and mandatory subjects on ME inthe dentistry curricula in Brazil and reflects the need to updateand standardize the national curricular guidelines for dentistry

Fatigue Behavior of Different CAD/CAM Materials for Monolithic, Implant-Supported Molar Crowns.

PURPOSE: To evaluate the fracture resistance after the thermal and mechanical fatigue of feldspathic, lithium disilicate, and resin-modified CAD/CAM monolithic crowns cemented onto a universal post abutment. MATERIALS AND METHODS: A right second mandibular molar was designed in CAD/CAM software, and 30 crowns were machined using three different materials (n = 10): feldspathic ceramic, finished only with a glaze cycle (G1); lithium disilicate, sintered and finished with a glaze cycle (G2); and resin, modified by nanoceramic and finished with rubber (G3). All crowns were cemented under a constant 50 N load, the excess cement was removed, and the crowns were light-cured for 30 seconds. After being immersed in deionized water for 7 days, the crowns were submitted to thermal cycling, which consisted of varying the temperature from 2 to 50°C for 350,000 cycles, and mechanical cycling in a fatigue simulator, where a 250 N load was applied for 1,000,000 cycles at 2 Hz. The resistance of each crown was verified in a compression-to-failure test at 1 mm/min in a universal test machine. The groups were compared using one-way ANOVA with a Bonferroni post hoc test and Weibull statistics. RESULTS: The resin-modified group was the least resistant group (1755 ± 124 N), followed by the feldspathic (2147 ± 412 N) and lithium disilicate groups (2804 ± 303 N). The Weibull statistics demonstrated that lithium disilicate is the most reliable material and has the lowest fracture probability. CONCLUSIONS: It was possible to conclude that all of the tested CAD/CAM materials can be used as monolithic, implant-supported molar crowns.

Avaliação biomecânica da angulação dos implantes posteriores nas reabilitações totais implantossuportadas em mandíbula através de método de elementos finitos / Biomechanical evaluation of hindraft implant anglulation in total implant-su-pported mandible rehabilitations through finite element method

Introdução: Como uma opção de tratamento ao edentulismo mandibular foi desenvolvido o conceito All-on-4®, uma técnica de ancoragem com a instalação de quatro implantes distribuídos na região anterior da mandíbula edêntula para uma reabilitação total implantossuportada. Objetivo: Neste estudo, analisamos pelo método de elementos finitos o comportamento biomecânico dos implantes e tecidos ósseos. Material e métodos: Foram utilizados 3 modelos tridimensionais computadorizados, cada um com 4 implantes hexágono externo 3,75x13mm na região interforames mentuais, os implantes anteriores mantidos na posição axial e a variação ocorreu nos implantes posteriores: grupo 1, implantes posteriores retos; grupo 2, implantes posteriores com inclinação em 17° e grupo 3, com implantes posteriores inclinados em 30°. Uma carga axial de 150N foi aplicada nos molares e de 100N nos pré-molares bilateralmente. Resultados: Após análises evidenciou-se que nos grupos 17° (13,68Mpa, 34,76Mpa e 14,36Mpa para as tensões de tração, compressão e cisalhamento respectivamente) e 30° (14,26Mpa, 23,14Mpa e 10,31Mpa para as tensões de tração, compressão e cisalhamento respectivamente) apresentaram menores picos de tensão no osso. O mesmo padrão de distribuição de tensões foi observado para os implantes, com redução quando inclinamos os implantes distais. Conclusão: Os resultados mostraram que a angulação dos implantes favoreceu a distribuição das tensões no osso e implantes, interferindo positivamente na performance biomecânica das reabilitações totais implantossuportadas em mandíbulas edêntulas, considerando que no grupo dos implantes retos os valores das tensões foram maiores.

Introduction: As a treatment option for mandibular edentulism, the All-on-4® concept was developed, an anchoring technique with the installation of four implants distributed in the anterior region of the edentulous mandible for total implant-supported rehabilitation. Objective: In this study, we analyzed by the finite element method the biomechanical behavior of implants and bone tissues. Material and methods: Three computerized three-dimensional models were used, each with 4 external hexagon 3.75x13mm implants in the mental interforam region, the anterior implants kept in the axial position and the variation occurred in the posterior implants: group 1, straight posterior implants; group 2, posterior implants inclined at 17° and group 3, posterior implants inclined at 30°. An axial load of 150 N was applied to the molars and 100 N to the premolars bilaterally. Results: After analysis, it was found that in the 17° (13.68Mpa, 34.76Mpa and 14.36Mpa groups for tensile, compressive and shear stresses respectively) and 30 ° (14.26Mpa, 23.14Mpa and 10.31Mpa for tensile, compressive and shear stresses respectively) presented lower stress peaks in the bone. The same pattern of stress distribution was observed for the implants, with reduction when the distal implants were tilted. Conclusion: The results showed that the angulation of the implants favored the distribution of stresses in the bone and implants, positively interfering in the biomechanical performance of the total implant-supported rehabilitations in edentulous jaws, considering that in the group of straight implants the stress values were higher.

Nível de conhecimento sobre suporte básico de vida dos estudantes de odontologia / Knowledge level of basic life support among dentistry students

Introdução: As doenças cardiovasculares são responsáveis por vinte por cento das mortes na população acima de trinta anos de idade e correspondem a um grave problema da saúde pública no Brasil.Dessas doenças a parada cardiorrespiratória é o quadro emergencial predominante. Nesse contexto, destaca-se a importância do conhecimento sobre as manobras de suporte básico de vida e manutenção da vida do paciente até a chegada de uma equipe de suporte avançado. Objetivo: Avaliar o nível de conhecimento dos estudantes de Odontologia da Universidade Federal de Juiz de Fora quanto ao suporte básico de vida. Material e métodos: Questionário contendo questões de múltipla escolha, aplicado a 126 alunos, abordando as condutas para o suporte básico de vida de acordo com as diretrizes atuais da American Heart Association. Para avaliar o nível de conhecimento foram utilizadas duas categorias com base no percentual individual de acertos das questões: nível de conhecimento satisfatório (acertos ≥51%) e nível de conhecimento insatisfatório (acertos ≤50%).Resultados: 104 (82,5%) estudantes acertaram até 50% do questionário. 100 estudantes (79,4%) responderam não ter recebido treinamento prático para o suporte básico de vida, enquanto que 26 (20,6%) afirmaram ter recebido algum treinamento, embora sem certificação pela American Heart Association.Quanto à capacitação teórica, 77(61,1%) estudantes afirmaram ter recebido alguma orientação durante a graduação. Ao comparar os resultados entre os alunos do 1º, 6º e 10º período, observa-se uma evolução do conhecimento apenas entre o 1º e o 6º período, não havendo melhoria significante no aprendizado entre o 6º e 10º período. Conclusão:Os estudantes de Odontologia do campus sede da Universidade Federal de Juiz de Fora apresentam nível de conhecimento insatisfatório sobre a atuação no suporte básico de vida.

Introduction: The cardiovascular diseases are responsible for twenty percent of deaths among the population over thirty years of age, which means they are a serious public health problem in Brazil, being the cardiopulmonary arrest the main emergency situation of these diseases. In this context, the knowledge about the basic life support is crucial for the maintenance of the patient's life until the arrival of advanced support. Objective: Evaluating the knowledge of the dentistry students of the Juiz de Fora Federal University about basic life support. Material and methods: A questionnaire applied to 126 students, composed by fourteen multiple choice questions about the conduct for basic life support according to the current guidelines of the American Heart Association. In order to evaluate the knowledge level, two different categories based on the student's score have been utilized: satisfactory knowledge level (rightanswers≥51%) and unsatisfactory knowledge level (rightanswers≤50%). Results: 104 (82,5%) of the students scored up to 50% of the questionnaire. 100 students (79,4%) claimed that they hadn't received any training for basic life support, while 26 (20,6%) claimed that they had received some training, although without the American Heart Association certification. 77 (61,1%) claimed that they had received some theoretical orientation during the graduation. By comparing the results between1st, 6th and 10th grade students, evolution has only been noticed between 1st and 6th grades. However, no significant evolution has been noticed between 6thand 10th grades. Conclusion: The dentistry students of the Juiz de Fora Federal University have presented unsatisfactory knowledge level on basic life support.

Effect of anatomical region on the formation of metal artefacts produced by dental implants in cone beam computed tomographic images.

OBJECTIVES: To quantitatively compare metal artefacts produced by implants in different maxillomandibular regions on cone beam CT (CBCT) images. METHODS: A total of 200 implants selected from CBCT examinations were divided into four groups: Group 1 (n = 50)-implants located in the anterior maxilla; Group 2 (n = 50)-implants located in the posterior maxilla; Group 3 (n = 50)-implants located in the anterior mandible and Group 4 (n = 50)-implants located in the posterior mandible. The implants were further classified as isolated or adjacent to other implants. Three axial reconstructions were selected for each sampled implant (apical, middle and cervical). On each slice, the artefacts produced by the implants were counted. The Mann-Whitney test was used to compare the variables between groups. The Kruskal-Wallis and Student-Newman-Keuls tests were used to compare the axial reconstructions. RESULTS: The mandible showed a greater number of artefacts than the maxilla (apical image: p = 0.0024; middle image: p < 0.0001). The anterior region produced more artefacts than the posterior region (apical image: p = 0.0105; middle image: p < 0.0316). There was no significant difference in the number of artefacts between isolated and adjacent implants, and the cervical image was most affected by artefacts. CONCLUSIONS: Dental implants always produce metal artefacts in CBCT images, and these artefacts are affected by the anatomical location in the dental arch.

Uma atualização sobre biomateriais em implantodontia / Biomaterials in Implantology: an update

O processo alveolar é uma estrutura dente dependente que sofre alterações dimensionais após a exodontia. Defeitos ósseos resultantes prejudicam a colocação de implantes e o sucesso em longo prazo. Diversas técnicas cirúrgicas e biomateriais tem sido apresentados como opções terapêuticas para preservação e recuperação dos rebordos edêntulos. Assim, o objetivo desta revisão narrativa é evidenciar o estado atual dos biomateriais disponíveis bem como as possíveis perspectivas futuras. A utilização de biomateriais para cirurgias de reconstrução e manutenção de rebordo alveolar com sucesso é evidente. As cirurgias de reconstrução e preservação de rebordo alveolar com a utilização de novos biomateriais apresentam sucesso evidente. A impressão em 3D de estruturas biocompatíveis, fatores de crescimento, a matriz de dentina desmineralizada (DDM), parafusos e membranas reabsorvíveis podem ser as perspectivas futuras.

The alveolar bone depends on the presence of teeth and dimensional changes occurs after tooth extraction. The resulting bone defects impair both implant installation and long term success. Surgical procedures and biomaterials are considered as treatment options for maintenance and recovery of edentulous ridge. Thus, the aim of this narrative review is to present the current biomaterials as well as future perspectives. Surgical procedures for alveolar ridge preservation and reconstruction with new biomaterials are successful. 3D-Printed biocompatible scaffolds, growth factors, decellularized extracellular matrix (dECM), resorbable pins and membranes could be the future perspectives.

Three-dimensional analysis of impacted maxillary third molars: A cone-beam computed tomographic study of the position and depth of impaction.

PURPOSE: The classification of impacted maxillary third molars (IMTMs) facilitates interdisciplinary communication and helps estimate the degree of surgical difficulty. Thus, this study aimed to develop a 3-dimensional classification of the position and depth of impaction of IMTMs and to estimate their prevalence with respect to gender and age. MATERIALS AND METHODS: This cross-sectional retrospective study analyzed images in sagittal and coronal cone-beam computed tomography (CBCT) sections of 300 maxillary third molars. The proposed classification was based on 3 criteria: buccolingual position (buccal, lingual, or central), mesial-distal position (mesioangular, vertical, or distoangular), and depth of impaction (low, medium, or high). CBCT images of IMTMs were classified, and the associations of the classifications with gender and age were examined using analysis of variance with the Scheffé post-hoc test. To determine the associations among the 3 classifications, the chi-square test was used (P<.05). RESULTS: No significant association of the classifications with gender was observed. Age showed a significant relationship with depth of impaction (P=.0001) and mesial-distal position (P=.005). The most common positions were buccal (n=222), vertical (n=184), and low (n=124). Significant associations among the 3 tested classifications were observed. CONCLUSION: CBCT enabled the evaluation of IMTMs in a 3-dimensional format, and we developed a proposal for a new classification of the position and depth of impaction of IMTMs.

Tratamento cirúrgico e conservador de cisto periapical de grande proporção: relato de caso / Surgical and conservative treatment of large periapical cyst: case report

O objetivo deste estudo foi descrever uma técnica de tratamento conservadora, cuja conduta preconizada foi a realização da descompressão seguida pela enucleação cística através do relato de um caso de cisto periapical de grande extensão. Paciente de 50 anos de idade, melanoderma, apresentando cisto periapical com aproximadamente 4,5 cm em seu maior diâmetro associado ao incisivo central inferior esquerdo. Na primeira etapa do tratamento, foi realizada descompressão cística e biopsia incisional, cujo exame histopatológico confirmou o diagnóstico clínico. Após 25 semanas de acompanhamento, houve uma considerável regressão do tamanho da lesão e a mesma foi enucleada sem comprometimento dos elementos dentários envolvidos e dos tecidos adjacentes. O relato de caso evidenciou que o tratamento cirúrgico e conservador pode ser um recurso em cistos periapicais de maior dimensão, sendo importante a cooperação do paciente no acompanhamento pós-operatório.

The aim of this study was to describe a conservative treatment technique, the recommended therapeutic of which was performed decompression and followed by cystic enucleation through the report of a large periapical cyst case. A 50-year-old melanoderma patient presented a periapical cyst with approximately 4,5 cm in its largest diameter associated with the left lower central incisor. In the first stage of the treatment, cystic decompression and incisional biopsy were performed; whose histopathological examination confirmed the clinical diagnosis. After follow-up, there was a considerable regression of the size of the lesion and it could be enucleated without compromising the dental elements involved and adjacent tissues. The case report showed that surgical and conservative treatment may be a resource in larger periapical cysts, and patient cooperation in postoperative follow-up is very important.

Evaluation of bone remodeling around single dental implants of different lengths: a mechanobiological numerical simulation and validation using clinical data.

Algorithmic models have been proposed to explain adaptive behavior of bone to loading; however, these models have not been applied to explain the biomechanics of short dental implants. Purpose of present study was to simulate bone remodeling around single implants of different lengths using mechanoregulatory tissue differentiation model derived from the Stanford theory, using finite elements analysis (FEA) and to validate the theoretical prediction with the clinical findings of crestal bone loss. Loading cycles were applied on 7-, 10-, or 13-mm-long dental implants to simulate daily mastication and bone remodeling was assessed by changes in the strain energy density of bone after a 3, 6, and 12 months of function. Moreover, clinical findings of marginal bone loss in 45 patients rehabilitated with same implant designs used in the simulation (n = 15) were computed to validate the theoretical results. FEA analysis showed that although the bone density values reduced over time in the cortical bone for all groups, bone remodeling was independent of implant length. Clinical data showed a similar pattern of bone resorption compared with the data generated from mathematical analyses, independent of implant length. The results of this study showed that the mechanoregulatory tissue model could be employed in monitoring the morphological changes in bone that is subjected to biomechanical loads. In addition, the implant length did not influence the bone remodeling around single dental implants during the first year of loading.

Associação terapêutica de dexametasona e meloxicam no controle inflamatório, após cirurgias de terceiros molares / Combination therapeutic dexamethasone and meloxicam in inflammatory controlafter third molars surgery

Os corticosteroides (CS) e anti-inflamatórios não esteroides (AINES) têm sido usados na busca do controle de processos inflamatórios em pacientes submetidos a cirurgias. O objetivo deste estudo foi avaliar o efeito entre o uso exclusivo de dexametasona e a associação desta e meloxicam no controle de edema, trismo e dor após selecionaram se cirurgias de terceiros molares inclusos. 15 pacientes com terceiros molares mandibulares inclusos (3MI) em posições simétricas, divididos por sorteio em grupos terapêuticos (GT). No grupo 1(GT1), receberam dose única via oral de 12 mg de dexametasona uma hora antes do procedimento cirúrgico; grupo 2 (GT2), 12 mg de dexametasona uma hora antes do procedimento cirúrgico e 15 mg de meloxicam no pós-operatório imediato por via oral, mantido a cada 24 horas, durante 3 dias. O edema e trismo foram avaliados, respectivamente, através de mensurações lineares da face e da distância interincisal pré e pós-operatória (24, 48 e 72h). A intensidade de dor foi avaliada através da escala visual analógica (EVA). Os dados foram submetidos ao teste t-student e teste Levene (p<0,05). As medidas de edema e trismo não apresentaram diferenças estatisticamente significativas. A associação resultou em menor intensidade de dor com diferença estatisticamente significativa. Concluiu-se que as duas terapias foram válidas no controle do edema e trismo, sendo a terapia combinada de dexametasona e meloxicam mais eficiente no controle da dor... (AU)

This Corticosteroids and anti-inflammatory non-steroidal drugs have been used in the search control inflammation of patients submitted to dental surgery. The goalwastoevaluate the effect of exclusive use of dexamethasoneandcombinationofdexamethasoneandmeloxicam in control of edema, trismus and pain following the extraction of impacted third molars (3MI). Fifteen healthy patients with indication for removal third molars in symmetricalpositionswereselected, dividedbydrawlot in therapeuticgroups (GT). In group1 (GT1), received a single oral dose of dexamethasone 12 mg one hour before the surgical procedure; in group 2 (GT2), oral dose of dexamethasone 12 mg one hour beforesurgery, and oral dose of 15 mg of meloxicamimmediatelypostoperative oral, at 24, 48 e 72h following surgery. At 24, 48 and 72 h following surgery, swelling was determine dusing linear measurement son the face andtrismus, by maximal mouth opening. Postoperative pain was self-recorded by patientsusing a visual analoguescale (VAS). Data analysisinvolved t-studentte stand Levenetest (p <0.05). Edema measures and trismus showed no statistically significant differences. The combination the rapeuticresulted in less pain with statistically significant difference. In conclusion, both the rapieswerevalids in controlling edema andtrismus, and combination the rapeutic more effective in pain control... (AU)

Development of estimation models of bone height considering the potential presence of anterior extension of the mandibular canal.

PURPOSE: To evaluate the presence of the anterior extension (AE) of the mandibular canal and to measure the bone height (BH) at different points along the extension. MATERIALS AND METHODS: Cone-beam computed tomography examinations of 108 patients were bilaterally evaluated regarding the presence of the AE, and linear measurements of the AE and BH were obtained. For comparisons between sides and genders, Student t test was applied. Variations in BH measurements were assessed by a 2-way analysis of variance. Through a simple linear regression analysis, formulas were determined for calculations of the BH in the AE. RESULTS: A right AE was detected in 76.9% and left AE in 77.8% of the samples. In the majority of the cases, the extension was of the rectilinear type. The mean length of the AE was 8.5 mm, and there was no statistically significant difference observed in relation to gender or side. It was observed that the BH increases as it approaches the midline. CONCLUSION: The AE of the mandibular canal must be evaluated during presurgical planning. The formulae presented in this study provide a method to calculate BH values in the interforaminal region and can be used to assist in presurgical planning, especially in the cases in which the identification of the hipodense site, which corresponds to the AE, is not evident.