Neuza Maria Souza Picorelli Assis

Maurício Silva Demétrio, Saulo de Matos Barbosa, Raphaela Kassia Lima, Yuri de Lima Medeiros, Daniel Amaral Alves Marliére, Neuza Maria Souza Picorelli Assis. JKAOMS 2025;51:108-16. https://doi.org/10.5125/jkaoms.2025.51.2.108

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.

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.

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.

Os concentrados de Plaquetas (CPs), como a Fibrina Rica em Plaquetas (PRF) são utilizados em Odontologia com o intuito de melhorar a cicatrização. Um dos procedimentos cirúrgicos onde este material é mais utilizado é na cirurgia de elevação do assoalho sinusal (EAS). Pode auxiliar tanto a regeneração de tecidos duros quanto moles e pode ser utilizado sozinho ou com outros biomateriais e auxiliar na prevenção e tratamento da perfuração da membrana de Schneider. O objetivo deste estudo foi revisar a literatura sobre a PRF e suas aplicações na cirurgia de levantamento de assoalho de seio maxilar. Foi realizado uma busca de artigos, na língua inglesa, utilizando as bases de dados LILACS, Pubmed e Google Scholar, no período de 2006 a 2021. Os artigos científicos incluíram estudos clínicos, revisões de literatura e revisões sistemáticas. A PRF se mostrou um método fácil, simples e econômico de auxílio na reparação tecidual. Pode auxiliar na correção de deficiências de altura óssea, complementando e auxiliando positivamente a cirurgia de levantamento de assoalho sinusal. No entanto, ainda não existe um consenso em relação à sua contribuição efetiva na cirurgia de levantamento de seio. Assim, mais estudos randomizados e utilizando o mesmo protocolo de obtenção deste concentrado de plaquetas são necessários.

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. A impressão em 3D de estruturas biocompatíveis, fatores de crescimento, as DDMs, parafusos e membranas reabsorvíveis podem ser as perspectivas futuras.

Rafael Guimar?es Lima, DDS, MS/Tito Guimar?es Lima, DDS, MS/Carlos Eduardo Francischone, DDS, MS, PhD/Cecilia Turssi, DDS, MS, PhD/Neuza Maria Souza Picorelli Assis, DDS, MS, PhD/Bruno Salles Sotto-Maior, DDS, MS, PhD: Purpose: The aim of this study was to evaluate volumetric stability of autologous and xenogeneic block grafts and primary stability of implants in maxillary grafted areas. Materials and Methods: Each patient received one autologous block and xenogeneic block, both covered with a membrane. Bone thickness measurements clinically and tomographically were made before, immediately, and 6 months postoperatively. After 6 months, identical implants were placed in each grafted area, and primary stability was measured. Results: Eight patients with anterior horizontal bone defects were selected. Clinical outcomes at 6 months postgrafting in the autologous block revealed a mean thickness of 7.4 ? 1.6 mm, with an initial mean measurement of 3.4 ? 1.7 mm and 2.6% resorption, whereas the mean in the xenogeneic block was 8.9 ? 1.5 mm, 3.3 ? 1.6 mm, and 7.3%, respectively. Tomographic evaluation of the thickness at 6 months postgrafting in the autologous block was a mean 7.8 ? 1.8 mm, with an initial mean of 3.7 ? 1.6 mm and resorption of 0%, while the mean in the xenogeneic block was 9.3 ? 1.6 mm, 3.6 ? 1.4 mm, and 2.1%, respectively. No significant difference in bone thickness was observed immediately or 6 months after the procedure. The mean implant placement torque was 32 ? 22 Ncm in the autologous block and 18 ? 9 Ncm in the xenogeneic block (P = .004). Conclusion: Xenogeneic block was shown to be a suitable alternative to reconstruct horizontal defects in the alveolar ridge that had undergone extensive resorption, though lower insertion torques were obtained during implant placement.

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.

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.