Publications by authors named "Rubens Spin-Neto"

99 Publications

Sella Turcica Area and Location of Point Sella in Cephalograms Acquired with Simulated Patient Head Movements.

J Contemp Dent Pract 2021 Mar 1;22(3):207-214. Epub 2021 Mar 1.

Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark, e-mail:

Aim And Objective: This study assesses changes in the sella turcica area (STA) and location of the cephalometric point sella (S) on lateral cephalograms acquired by charge-coupled device (CCD)-based cephalostats with and without simulated patient head movements.

Materials And Methods: A real skull was placed on a robot, able to simulate four head movements (anteroposterior translation/lifting/nodding/lateral rotation) at three distances (0.75/1.5/3 mm) and two patterns (returning to 0.5 mm away from the start position/staying at maximum movement excursion). Two ProMax-2D cephalostats (Dimax-3, D-3 or Dimax-4, D-4), and an Orthophos-SL cephalostat (ORT) acquired cephalograms during the predetermined movements ("cases," 48 images/unit) and without movement ("controls," 24 images/unit). Three observers manually traced the contour of sella turcica and marked point sella using a computer mouse. STA was calculated in pixels by dedicated software based on the tracing. S was defined by its and coordinates recorded by the same software in pixels. Ten percent of the images were assessed twice. The difference between cases and controls (case control) for the STA and S (namely Diff-STA and Diff-S) was calculated and assessed through descriptive statistics.

Results: Inter- and intraobserver agreement ranged from moderate to good for STA and S. Diff-STA ranged from -42.5 to 12.9% (D-3), -15.3 to 9.6% (D-4), and -25.3 to 39.9% (ORT). Diff-S was represented up to 50% (D-3), 134% (D-4), and 103% (ORT) of the mean sella turcica diameter in control images.

Conclusion: Simulated head movements caused significant distortion in lateral cephalograms acquired by CCD-based cephalostats, as seen from STA and S alterations, depending on the cephalostat.

Clinical Significance: Patient-related errors, including patient motion artifacts, are influential factors for the reliability of cephalometric tracing.
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March 2021

Fully versus conventionally guided implant placement by dental students: A randomized controlled trial.

Clin Oral Implants Res 2021 Jun 24. Epub 2021 Jun 24.

Oral Rehabilitation, Section for Oral Health, Society and Technology, Department of Odontology, Faculty of Health and Medical Sciences Sciences, University of Copenhagen, Copenhagen, Denmark.

Objective: To compare fully guided with conventionally guided implant surgery performed by dental students in terms of deviation of actual implant position from an ideal implant position.

Materials And Methods: Twenty-five patients in need of 26 straightforward implant-supported single crowns were randomly allocated to a fully guided (FG, n = 14) or a conventionally guided (CG, n = 12) implant surgery. In the preoperative CBCTs, 3 experienced investigators placed a virtual implant in the ideal position, twice, allowing deviational analysis in the facio-lingual (coronal) and mesio-distal (sagittal) planes for 7 parameters. Facio-lingual crestal deviation, facio-lingual apical deviation, facio-lingual angular deviation, mesio-distal crestal deviation, mesio-distal apical deviation, mesio-distal angular deviation, and vertical deviation between the ideal, virtually placed position and actual implant position for the FG and CG groups were compared statistically (p < .05).

Results: Statistically significant differences between ideal and actual implant position were only seen for the facio-lingual apical deviation (p = .047) and for the facio-lingual angular deviation (p = .019), where the CG group deviated more from the ideal position than the FG group. The 5 other examined variables did not show any significant differences, and none of the implants in the FG group and CG group were placed in conflict with the clinical guidelines.

Conclusions: The present study reported no difference in 5 out of 7 deviational parameters concerning actual implant position in relation to ideal implant position between a FG and CG implant placement protocol performed by dental students. Facio-lingual angular deviation and apical deviation were lower, when a FG protocol was followed. All implants were positioned according to clinical guidelines.
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http://dx.doi.org/10.1111/clr.13802DOI Listing
June 2021

Magnetic Resonance Imaging for the Planning, Execution, and Follow-up of Implant-Based Oral Rehabilitation: Systematic Review.

Int J Oral Maxillofac Implants 2021 May-Jun;36(3):432-441

Purpose: To undertake a systematic literature review of magnetic resonance imaging (MRI) employed in the three phases of implant-based oral rehabilitation: planning, execution, and follow-up.

Materials And Methods: MEDLINE (PubMed) and EMBASE bibliographic databases were searched up to January 2020 for studies assessing the use of MRI alone or in connection with CT and/or CBCT in the planning, execution, or follow-up of dental implant placement and/or bone grafting procedures in the maxilla or the mandible. Included studies were also assessed according to the diagnostic imaging efficacy scale presented by Fryback and Thornbury (F&T).

Results: The search strategy yielded 10 studies, which were included in the systematic review. Six studies focused on the implant planning phase, one on the immediate follow-up phase, and three on both planning and follow-up. No studies acquired signal from the bone. There was no consensus on the gold standard, MRI sequence, or field strength (T). One study reached F&T level 1, eight reached level 2, and one reached level 3.

Conclusion: The possible transition from radiography to ionizing-radiation-free imaging through MRI is still a novelty in dentistry and has yet to establish itself as a viable imaging modality suitable for replacing CT and CBCT. More studies are needed on the accuracy of the diverse MRI possibilities when applied for implant planning, execution, and follow-up before this diagnostic method can be considered as a reality for the clinician.
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http://dx.doi.org/10.11607/jomi.8536DOI Listing
June 2021

Cortical Bone Modifications after Radiotherapy: Cortex Porosity and Osteonal Changes Evaluated Over Time.

Braz Dent J 2021 Jan-Feb;32(1):9-15

Periodontology Department, Faculty of Dentistry, UFU - Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.

Aiming to evaluate cortical bone microarchitecture and osteonal morphology after irradiation, twelve male New Zealand rabbits were used. The animals were divided: control group (no radiation-NIr); and 3 irradiated groups, sacrificed after: 7 (Ir7d); 14 (Ir14d) and 21 (Ir21d) days. A single radiation dose of 30 Gy was used. Computed microtomography analyzed the cortical microarchitecture: cortical thickness (CtTh), bone volume (BV), total porosity (Ct.Po), intracortical porosity (CtPo-cl), channel/pore number (Po.N), fractal dimension (FD) and degree of anisotropy (Ct.DA). After scan, osteonal morphology was histologically assessed by means: area and perimeter of the osteons (O.Ar; O.p) and of the Haversian canals (C.Ar; C.p). Microtomographic analysis were performed by ANOVA, followed by Tukey and Dunnet tests. Osteon morphology analyses were performed by Kruskal-Wallis, and test Dunn's. Cortical thickness was significant difference (p<0.010) between the NIr and irradiated groups, with thicker cortex at Ir7d (1.15±0.09). The intracortical porosity revealed significant difference (p<0.001) between irradiated groups and NIr, with lower value for Ir7d (0.29±0.09). Bone volume was lower in Ir14d compared to control. Area and perimeter of the osteons were statistically different (p<0.0001) between NIr and Ir7d. Haversian canals also revealed lower values (p<0.0001) in Ir7d (80.57±9.3; 31.63±6.5) compared to NIr and irradiated groups. Cortical microarchitecture was affected by radiation, and the effects appear to be time-dependent, mostly regarding the osteons morphology at the initial days. Cortex structure in Ir21d revealed similarities to control suggesting that microarchitecture resembles normal condition after a period.
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http://dx.doi.org/10.1590/0103-6440202103384DOI Listing
May 2021

Radiographic changes in height and volume after lateral GBR procedures with different ratios of deproteinized bovine bone mineral and autogenous bone at different time points. An experimental study.

Clin Oral Implants Res 2021 Feb 22;32(2):167-179. Epub 2020 Dec 22.

Department of Oral and Maxillofacial Surgery, Aalborg University Hospital and Department of Clinical Medicine, The Faculty of Medicine, Aalborg University, Aalborg, Denmark.

Objective: Estimate changes in augmentation height and volume after lateral guided bone regeneration (GBR) augmentation with different ratios of deproteinized bovine bone mineral (DBBM) and particulate autogenous bone (PAB) and autogenous bone block (ABB), at different time points.

Material And Methods: Twenty-four minipigs were randomly allocated into three healing periods. Lateral augmentation in 96 sites with standardized quantity of graft material was performed with different ratios of DBBM and PAB (50:50, 75:25, and 100:0) and ABB in combination with DBBM, covered by a collagen membrane. Changes in augmentation height and volume were assessed on CT volumes acquired 10, 20, and 30 weeks after surgery.

Results: Reduction in bone augmentation height was as follows: 50:50-1.7 mm (-33.1%), 75:25-1.8 mm (-37.8%), 100:0-1.7 mm (-35.8%), and ABB - 0.2 mm (-3.7%), after 30 weeks. The augmentation height was significantly better preserved with ABB compared to 50:50, 75:25, and 100:0, while no significant difference was present among particulate grafts. No significant difference in volumetric reduction was found among 50:50, 75:25, 100:0 and ABB after 30 weeks, while 100:0 presented significant less reduction compared to 50:50, 75:25 and ABB after 10 and 20 weeks.

Conclusions: Augmentation height following GBR was better preserved with ABB covered with DBBM. Addition of PAB to DBBM did not affect the changes in height of the graft. The volumetric stability seems to be comparable for ABB covered by DBBM and all particulate grafts after 30 weeks. However, DBBM alone revealed significant less volume reduction in the early healing phase.
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http://dx.doi.org/10.1111/clr.13687DOI Listing
February 2021

Head motion and perception of discomfort by young children during simulated CBCT examinations.

Dentomaxillofac Radiol 2021 Mar 30;50(3):20200445. Epub 2020 Oct 30.

Oral Radiology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.

Objectives: To assess the frequency and characteristics (number, complexity, and distance) of head movements, and the perception of discomfort during simulated CBCT examinations in children, considering units with different patient positioning method and head immobilization device combinations.

Methods: Forty children (20 boys/20 girls, age range 10-14 years) were video-recorded during simulated CBCT examinations. Children were randomly allocated to a sequence of five CBCT units: Newtom-5G, Orthophos-SL, Cranex-3Dx (patient standing/sitting), and X1. The child scored his/her discomfort perception (visual scale) and the preferred/ill-favored unit. Three observers scored the videos (20% in duplicate): child movement (yes/no), number (<3/≥3/continuous), complexity (uniplanar/multiplanar) and distance (<3 mm/≥3 mm). κ statistics provided intra-/interobserver reproducibility. Severe/extreme motion was defined based on movement characteristics. Chi-square tests assessed the frequency differences of severe/extreme motion among the units, age and operator. Logistic regression analyses with severe/extreme motion as outcome were performed.

Results: The range of ntra- and inter-observer reproducibility for movement observation was 0.78-0.89 and 0.61-0.64, respectively. Between 60% (Newtom-5G) and 100% (X1) of children moved during the examination. Severe/extreme motion was significantly related to unit and age. There was significantly less severe/extreme motion, when the child was in the supine position with a foam headrest as head support. The younger the child, the higher the risk for severe/extreme motion. The majority of the children preferred the unit with the supine position and a foam headrest.

Conclusions: The prevalence of severe and extreme motion was associated with the unit's patient positioning method and head immobilization devices combined, and child age.
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http://dx.doi.org/10.1259/dmfr.20200445DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7923072PMC
March 2021

Effect of a formalin-based fixation method on bone mineral content in human specimens.

Acta Odontol Scand 2021 Apr 13;79(3):212-217. Epub 2020 Oct 13.

Section of Oral Radiology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.

Objective: Histopathology of formalin-fixated human specimens may be used as reference standard for evaluation of diagnostic index tests like CBCT or MRI. The aim was to estimate changes in bone mineral content (BMC) over time in human bone specimens fixated in a formalin-based solution for 24 h followed by storage in an alcohol-based medium for six months, assessed by dual-energy X-ray absorptiometry (DXA).

Methodology: Bone specimens ( = 19) from human mandibles donated for science were included. BMC was measured by DXA before fixation (D), after 24 h of immersion fixation in a formalin-based solution (D), and hereafter every 30 days (M-M) during storage in a 30% ethanol-based storage medium for 6 months. Changes in BMC from D to D and from D to M were calculated and mean change in BMC estimated.

Results: Mean change in BMC from D to D was -0.73% (95% CI -1.75%; 0.29%), and from D to M -1.19% (95% CI -2.14%; -0.23%).

Conclusions: No changes in BMC of human bone specimens were found after 24 h formalin-based immersion fixation. After six months storage in an ethanol-based medium, BMC mean loss of 1% was detected. In this range, changes in BMC are not clinically relevant.
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http://dx.doi.org/10.1080/00016357.2020.1832701DOI Listing
April 2021

Alendronate Impairs Healing of Calvaria Critical Defects After Bone Graft With Different Bone Substitute Materials.

J Oral Maxillofac Surg 2020 Dec 27;78(12):2184-2194. Epub 2020 Aug 27.

Associate Professor, Department of Periodontology, Dental School, UFU - Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil. Electronic address:

Purpose: The aim of this preclinical study was to evaluate the healing of critical-sized defects (CSDs) in the calvarial bone of rats grafted with deproteinized bovine bone graft (DBB) and with a combination of hydroxyapatite (HA) and β-tricalcium phosphate (TCP) and bisphosphonate treatment.

Materials And Methods: Eighty-four animals were randomly divided into 2 groups according to the type of solution administered: the control group (CTR, saline solution) and the test group (alendronate [ALD]; sodium alendronate-50 μg/kg/day). Medications were administered via oral gavage starting 15 days before the surgical procedure until the end of the experiment. A CSD (5 mm in diameter) was made in the calvaria of each animal, and the rats were randomly allocated to 3 subgroups according to the biomaterial used to fill the defect: coagulum, DBB, and HA/TCP. The animals were sacrificed 15 and 60 days after the surgical procedure (n = 7 animals/period/subgroup). Microcomputed tomography was used to evaluate the percentage of mineralized tissues (volume). The amount of newly formed bone and remaining bone substitute material in the calvaria were analyzed by histomorphometry.

Results: There were no differences between the CTR and ALD groups with regard to the volume of mineralized tissues. The DBB and HA/TCP subgroups of CTR animals presented a significant increase in newly formed bone compared with these subgroups of ALD animals after 60 days of healing.

Conclusions: Collectively, our findings indicate that the use of oral ALD reduced bone formation in CSD in the calvaria of rats grafted with DBB and HA/TCP.
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http://dx.doi.org/10.1016/j.joms.2020.08.022DOI Listing
December 2020

Effect of section thickness on cone beam computed tomography-based measurements of intrabony defects compared with clinical measurements.

J Periodontol 2021 05 3;92(5):670-677. Epub 2020 Sep 3.

Department of Dentistry and Oral Health, Section of Oral Radiology, Aarhus University, Aarhus, Denmark.

Background: It is unknown whether cone beam computed tomography (CBCT) image reconstruction characteristics, including section thickness, may affect linear bone measurements of periodontal intrabony defects. The aim of this study was to compare intrasurgical and CBCT-based linear measurements of intrabony defects focusing on CBCT section thickness.

Methods: Sixty-six intrabony defects were assessed in 21 patients with chronic generalized severe periodontitis. Linear measurements of alveolar bone (radiographic bone level [rBL]), assessed in CBCT images at diverse section thicknesses: 0.25 mm (voxel size), 1 mm, and 3 mm, were compared with clinical bone level (cBL) measurements obtained intrasurgically. To provide identical reference points for rBL and cBL measurements, individually adjusted grooves on the reference stent were prepared for each periodontal defect site. CBCT measurements were performed in two rounds by two trained observers. Observer agreement was assessed by intraclass correlation coefficients (ICC). ANOVA assessed the difference among cBL and rBL at different section thicknesses.

Results: Intra- and inter-observer agreement was excellent (ICC >0.99) and highly significant independent of the observer, evaluation round, and CBCT section thickness. Mean rBL in the diverse CBCT section thicknesses was very close to that measured clinically (cBL). There was no statistically significant difference between cBL and rBL for any section thickness, neither for the overall evaluated sites, nor the maxilla or mandible separately.

Conclusions: No statistically significant difference between clinical and radiographic bone level for 0.25-, 1-, and 3-mm CBCT section thicknesses were observed when assessing intrabony periodontal defects.
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http://dx.doi.org/10.1002/JPER.20-0338DOI Listing
May 2021

Remodelling of sinus bone grafts according to the distance from the native bone: A histomorphometric analysis.

Clin Oral Implants Res 2020 Oct 1;31(10):959-967. Epub 2020 Sep 1.

Department of Diagnosis and Surgery, Araraquara Dental School, UNESP, Araraquara, Brazil.

Objectives: To evaluate graft remodelling according to the distance from the native bone in maxillary sinuses grafted with anorganic bovine bone (ABB).

Material And Methods: Bilateral sinus grafting was performed in twenty patients with residual bone height <5 mm before implant placement. After 8 months, biopsy samples were harvested, and histomorphometric analysis was performed to examine bone formation according to the distance (in mm) from the native bone (sinus floor). In the grafted area, the percentages of new bone (NB), residual graft material (rABB), and soft tissue (ST) were evaluated.

Results: A total of 103 biopsy samples were evaluated, and the percentages of NB, rABB, and ST were 31.62 ± 9.85%, 18.94 ± 7.88%, and 49.41 ± 9.52%, respectively, in the 1st mm; 27.15 ± 9.83%, 23.33 ± 9.45%, and 49.53 ± 11.73%, respectively, in the 2nd mm; 23.61 ± 13.02%, 21.35 ± 11.08%, and 55.03 ± 16.14%, respectively, in the 3rd mm; and 21.67 ± 12.29%, 19.67 ± 10.28%, and 58.66 ± 12.46%, respectively, in the 4th mm. The 1st millimetre of the grafted area (closer to the native bone) presented a larger amount of NB than the other portions of the grafted areas and a smaller amount of rABB than the 2nd mm of the grafted area (p < .05). The amount of ST was larger in the 3rd and 4th mm of the grafted area than in the first 2 millimetres (p < .05).

Conclusion: The distance from the native bone influences bone formation following maxillary sinus augmentation.
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http://dx.doi.org/10.1111/clr.13639DOI Listing
October 2020

Objective assessment of the combined effect of exomass-related- and motion artefacts in cone beam CT.

Dentomaxillofac Radiol 2021 Jan 19;50(1):20200255. Epub 2020 Aug 19.

Oral Radiology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.

Objectives: To assess quantitatively the combined effect of exomass-related- and motion artefacts on voxel value parameters in cone beam CT (CBCT).

Methods: A cylindrical phantom was manufactured, containing 21 tubes filled with a radiopaque solution, allowing the inclusion of three titanium implants in the periphery to induce exomass-related artefacts. The phantom was mounted on a robot simulating 0.75-, 1.5-, and 3 mm movements (nodding/lateral rotation/tremor). CBCT images with/without exomass and with/without movements were acquired in duplicate in three units: Cranex 3Dx, Orthophos SL-3D, and X1 (with motion-artefact correction). A cylindrical volume of interest was defined in each tube and voxel value mean and standard deviation were assessed. For each CBCT volume, the 21 mean voxel values were averaged providing the overall mean voxel value (MVV), and the standard deviation (among the 21 values) was calculated providing overall voxel value inhomogeneity (VVI). The standard deviation from each of the 21 volumes-of-interest were averaged, providing overall image noise (IN). The effect of the diverse tested situations was inferred from a repeated-measures analysis of variance, followed by Sidak's test ( = 0.05).

Results: Overall, images acquired with exomass showed significantly ( ≤ 0.05) lower MVV, and higher VVI and IN. Motion artefacts aggravated exomass-related alterations. MVV and VVI were mostly affected by 3 mm nodding movements. Motion-artefact correction eliminated the deleterious effect of movement.

Conclusions: CBCT voxel-value parameters are altered by exomass-related artefacts, and this finding is aggravated in the presence of motion artefacts. Motion-artefact correction effectively eliminated the deleterious impact of movement.
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http://dx.doi.org/10.1259/dmfr.20200255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7780835PMC
January 2021

Radiopacity of endodontic materials using two models for conversion to millimeters of aluminum.

Braz Oral Res 2020 15;34:e080. Epub 2020 Jul 15.

Department of Restorative Dentistry, Araraquara School of Dentistry, Universidade Estadual Paulista, Araraquara, SP, Brazil.

The aims of the present study were to compare conventional radiography, radiographs digitized with a scanner or photographic camera, and digital radiography, used to evaluate the radiopacity of endodontic materials, and to compare the accuracy of linear and quadratic models used to convert radiopacity values to equivalent millimeters of aluminum (mm Al). Specimens of AH Plus, Endofill, Biodentine and BioMTA materials (n = 8) were radiographed next to an aluminum step-wedge using radiographic films and digital radiography systems (FONA CMOS sensor, Kodak CMOS sensor and photosensitive phosphor plate-PSP). Conventional radiographs were digitized using a scanner or photographic digital camera. Digital images of all the radiographic systems were evaluated using dedicated software. Optical density units (ODU) of the specimens and the aluminum step-wedge were evaluated by a photo-densitometer (PTDM), used in conventional radiographs. The radiopacity in equivalent mm Al of the materials was determined by linear and quadratic models, and the coefficients of determination (R2) values were calculated for each model. Radiopacity of the materials ranged from -9% to 25% for digital systems and digitized radiographs, compared to the PTDM (p < 0.05). The R2 values of the quadratic model were higher than those of the linear model. In conclusion, the FONA CMOS sensor showed the lowest radiopacity variability of the methodologies used, compared with the PTDM, except for the BioMTA group (higher than PTDM). The quadratic model showed higher R2 values than the linear model, thus indicating better accuracy and possible adoption to evaluate the radiopacity of endodontic materials.
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http://dx.doi.org/10.1590/1807-3107bor-2020.vol34.0080DOI Listing
September 2020

Effect of computer-assisted-learning and simulation clinics on dental students' cognitive and performance skills: panoramic image errors related to patient's head position.

Dentomaxillofac Radiol 2020 Oct 18;49(7):20200154. Epub 2020 Jun 18.

Section for Oral Radiology, Department of Dentistry and Oral Health, Health Faculty, Aarhus University, Aarhus, Denmark.

Objectives: To assess dental students' ability to recognize head positioning errors in panoramic (PAN) images after individual learning via computer-assisted-learning (CAL) and in a simulation clinic (SIM). Both cognitive skills and performance in patient examination were assessed.

Methods And Materials: 60 students (mean age 23.25 years) participated in lectures on the relation between PAN-image errors and patient's head position. Immediately after they took a test, based on which they were randomized to three groups: control (CON) group, CAL group, and SIM group (both CAL and training in a simulation clinic with a phantom). 4-5 weeks after intervention/no intervention, all students individually examined a patient with PAN-exposure. A blinded rater, not knowing group allocation, supervised patient exposure and assessed student's performance (correct/incorrect head position in three planes). 1-2 weeks after, the students scored positioning errors in 40 PAN-images. Differences in cognitive test scores between groups were evaluated by ANOVA and in patient examination by χ tests, and within-group differences by sign-tests.

Results: No statistically significant difference in cognitive test scores was seen between the SIM and CAL group, while the CON group scored lower ( < 0.003). In all groups, several students positioned the patient incorrectly in the Frankfort horizontal plane. All students performed well in the sagittal plane. Students in SIM group positioned the patient more correctly in the coronal plane.

Conclusions: Training with CAL increased students' cognitive skills compared with a control group. Simulated patient exposure with a phantom increased to some extent their performance skills in examination of patients.
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http://dx.doi.org/10.1259/dmfr.20200154DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549529PMC
October 2020

Histology of augmented autogenous bone covered by a platelet-rich fibrin membrane or deproteinized bovine bone mineral and a collagen membrane: A pilot randomized controlled trial.

Clin Oral Implants Res 2020 Aug 14;31(8):694-704. Epub 2020 May 14.

Department of Dentistry and Oral Health, Section for Prosthetic Dentistry, Aarhus University, Aarhus C, Denmark.

Objectives: This study aimed to evaluate histologic and histomorphometric bone characteristics with a focus on vitality after lateral alveolar ridge augmentation using an autogenous bone graft as a block covered by either a platelet-rich fibrin (PRF) membrane (test group) or a standard procedure involving coverage of the bone block with a deproteinized bovine bone mineral and a resorbable collagen membrane (control group).

Material And Methods: A total of 27 (test = 14, control = 13) partially edentulous patients with indication for bone block augmentation before implant installation were included. For analyses, a biopsy of augmented bone was retrieved six months after bone grafting.

Results: Histologic evaluation of augmented bone revealed a predominance of non-vital bone toward the periosteum and few localized areas of vital bone in the center of the graft in both groups. In contrast, augmented bone toward the native bone demonstrated extensive bone remodeling in both groups. Histomorphometric analyses demonstrated a mean of 14% vital bone, 80% non-vital bone, 5% soft tissue, and 1% blood vessels in the test group. In the control group, the corresponding shares were 14% vital bone, 63% non-vital bone, 22% soft tissue, and 1% blood vessels. We observed no significant differences between the groups (p > .05).

Conclusion: In conclusion, a comparable low bone vitality of augmented bone was observed in the PRF and in the control group. Consequently, the present study could not verify the potential beneficial effect of a PRF membrane on bone vitality of an autogenous bone graft used as a block.
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http://dx.doi.org/10.1111/clr.13605DOI Listing
August 2020

Bone formation around two titanium implant surfaces placed in bone defects with and without a bone substitute material: A histological, histomorphometric, and micro-computed tomography evaluation.

Clin Implant Dent Relat Res 2020 Apr 23;22(2):177-185. Epub 2020 Feb 23.

Department of Diagnosis and Surgery, School of Dentistry, Sao Paulo State University, Araraquara, Brazil.

Objective: To evaluate the histological and microtomographic response of peri-implant bone tissue around titanium implants with different surface treatments, placed in bone defects filled or not filled with bone substitute materials.

Materials And Methods: Thirty rabbits were divided into two groups according to the implant surface treatment. A bone defect was created in both tibias of all the rabbits, followed by the placement of one implant in each of these defects. On the left tibia, the defect was filled with a blood clot (BC), and on the right tibia, the defect was filled with biphasic hydroxyapatite/β-tricalcium-phosphate (HA/TCP); thus, there were four groups in total: BC-N: bone defect filled with a BC and porous surface titanium implant (control group); BC-A: bone defect filled with a BC and porous-hydrophilic surface titanium implant; HA/TCP-N: bone defect filled with a bone substitute material and porous surface titanium implant; HA/TCP-A: bone defect filled with a bone substitute material and porous-hydrophilic surface titanium implant. The animals were submitted for euthanasia at three distinct periods: 15, 30, and 60 days after implant installation. The samples were evaluated histologically and histometrically, to assess the quantity and quality of cells and the remaining bone substitute material in the grafted areas. The bone quantity was assessed by micro-computed tomography (CT).

Results: For both surface types, the presence of a bone substitute material led to higher values in all evaluated micro-CT parameters, except in the bone surface/volume ratio parameter. No significant statistical difference was found for new bone formation between the four groups (P < .05; CI 95%). At all periods, the HA/TCP-A group had a higher percentage of new bone formation.

Conclusion: These results suggest that a porous hydrophilic surface in the presence of bone substitute material can accelerate peri-implant bone tissue formation.
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http://dx.doi.org/10.1111/cid.12880DOI Listing
April 2020

Cyclosporine A impairs bone repair in critical defects filled with different osteoconductive bone substitutes.

Braz Oral Res 2020 7;34:e007. Epub 2020 Feb 7.

Universidade Estadual de São Paulo - Unesp, School of Dentistry Araraquara, Department of Diagnosis and Surgery, Araraquara, SP, Brazil.

The aim of this study was to assess the influence of cyclosporine administration on the repair of critical-sized calvaria defects (CSDs) in rat calvaria filled with diverse biomaterials. Sixty animals were divided into two groups: the control (CTR) group (saline solution) and the cyclosporine (CCP) group (cyclosporine, 10 mg/kg/day). These medications were administered daily by gavage, beginning 15 days before the surgical procedure and lasting until the day the animals were euthanized. A CSD (5 mm Ø) was made in the calvaria of each animal, which was allocated to one of 3 subgroups, according to the biomaterial used to fill the defect: coagulum (COA), deproteinized bovine bone (DBB), or biphasic calcium phosphate ceramics of hydroxyapatite and β-phosphate tricalcium (HA/TCP). Euthanasia of the animals was performed 15 and 60 days after the surgical procedure (n = 5 animals/period/subgroup). Bone repair (formation) assessment was performed through microtomography and histometry, while the analyses of the expression of the BMP2, Osteocalcin, and TGFβ1 proteins were performed using immunohistochemistry. The CSDs not filled with biomaterials demonstrated lower bone formation in the CCP group. At 15 days, less bone formation was observed in the CSDs filled with DBB, a smaller volume of mineralized tissue was observed in the CSDs filled with HA/TCP, and the expression levels of BMP2 and osteocalcin were lower in the CCP group compared to the CTR group. The use of cyclosporine impaired bone repair in CSD, and this effect can be partially explained by the suppression of BMP2 and osteocalcin expression.
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http://dx.doi.org/10.1590/1807-3107bor-2020.vol34.0007DOI Listing
February 2020

Odontogenic Myxoma: Systematic review and bias analysis.

Eur J Clin Invest 2020 Apr 14;50(4):e13214. Epub 2020 Mar 14.

Oral Medicine, Department of Diagnosis and Surgery, School of Dentistry, São Paulo State University (UNESP), Araraquara, Brazil.

Background: Odontogenic myxoma (OM) is a rare neoplasm, which originates from odontogenic ectomesenchyme. There is no study in the literature that analyses the best standards for OM diagnosis and how the treatment modalities may influence the recurrence rates.

Objective: To evaluate the best standards for odontogenic myxoma (OM) diagnosis and treatment, and how these may influence the recurrence rates.

Study Design: Two independent researchers performed a systematic review in many databases. Fifty-two eligible studies were included for qualitative analysis. Bias analysis was conducted according to Oxford Centre for Evidence-Based Medicine.

Results: A total of 1363 OM cases were reported on, and female gender with average age of 27 years is the most common patient profile. Conventional microscopic findings were observed in 93.43% of the reported cases. In 57.49% of the cases, multilocular radiographic appearance was present, followed by unilocular appearance (32.87%). Posterior mandible was the site with the major prevalence, while surgical resection was the most common treatment modality, followed by enucleation. Recurrence rates for both treatment modalities were approximately close (13.04% and 25.0%, respectively).

Conclusion: The correct diagnosis of OM relies on the association of clinical, radiographic and microscopic findings. About imaging examinations, panoramic radiography and computed tomography are sufficient for the evaluation of OM. Recurrence rates were closely among the two most used surgery treatments. So according to some clinical-radiological aspects, conservative surgery may be preferred than aggressive surgery modalities.
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http://dx.doi.org/10.1111/eci.13214DOI Listing
April 2020

Image-stitching artefacts and distortion in CCD-based cephalograms and their association with sensor type and head movement: study.

Dentomaxillofac Radiol 2020 Mar 18;49(3):20190315. Epub 2019 Nov 18.

Department of Dentistry and Oral Health, Oral Radiology, Aarhus University, Vennelyst Boulevard 9, 8000, Aarhus, Denmark.

Objectives: To assess presence and severity of image-stitching artefacts and distortion in lateral cephalograms acquired by CCD-based sensors and their association with movement.

Methods: A human skull was mounted on a robot simulating five head movement types (anteroposterior translation/lifting/nodding/lateral rotation/tremor), at three distances (0.75/1.5/3 mm), based on two patterns (skull returning/not returning to the initial position, except for tremor). Three cephalometric units, two ProMax-2D (Planmeca Oy, Finland), one with Dimax-3 (D-3) and one with Dimax-4 (D-4) sensor, and one Orthophos-SL (ORT, Dentsply-Sirona, Germany), acquired cephalograms during the predetermined movements, in duplicate (54 with movement and 28 controls with no movement per unit). One observer assessed the presence of an image-stitching line (none/thin/thin with vertical stripes or thick), misalignment between the anatomical structure display (none/<1/1-3/>3 mm), and distortion in each image quadrant (present/absent), in duplicate. Severe image-stitching artefacts were defined for images scored with a thin line with vertical stripes or thick line and/or misalignment between anatomical structure display ≥1 mm. Severe distortion was defined for images scored with distortion in both anterior quadrants of the skull. κ-statistics provided intraobserver agreement.

Results: Intraobserver reproducibility was >0.8 (all assessed parameters). Severe image-stitching artefacts were scored in 70.4 and 18.5% of D-3 and D-4 movement images, respectively. Severe distortion was scored in 64.8% of D-3, 5.6% of D-4 and 37% of ORT movement images. Neither severe image-stitching artefacts nor severe distortion were observed in control images.

Conclusion: Sensor type, movement type, distance and pattern affected presence and severity of image-stitching artefacts and distortion in CCD-based cephalograms.
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http://dx.doi.org/10.1259/dmfr.20190315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7068076PMC
March 2020

Bone tissue formation around two titanium implant surfaces placed in bone defects filled with bone substitute material or blood clot: A pilot study.

Clin Implant Dent Relat Res 2019 Dec 6;21(6):1175-1180. Epub 2019 Nov 6.

Department of Diagnosis and Surgery, School of Dentistry, Sao Paulo State University, Araraquara, Brazil.

Objectives: The objective of this study was to evaluate the peri-implant bone tissue formation around titanium implants with different surface treatments, placed in bone defects filled or not with bone substitute material (BSM).

Materials And Methods: Ten animals were divided into two groups according to implant surface treatment. In each tibia, a bone defect was created followed by the placement of one implant. On the left tibia, the defect was filled with blood clot (BC), and on the right tibia, the defect was filled with biphasic hydroxyapatite/β-tricalcium-phosphate (HA/TCP) generating four subgroups: BC-N: blood clot and porous surface; BC-A: blood clot and porous-hydrophilic surface; HA/TCP-N: BSM and porous surface; HA/TCP-A: BSM and porous-hydrophilic surface. The animals were submitted to euthanasia 60 days after implant installation. After light-curing resin inclusion, the blocks containing the implant and the bone tissue were stained and evaluated by means of histomorphometry to assess the percentages of bone implant contact (% BIC). Data was normally distributed and the group differences were examined using the parametric tests of Two-Way ANOVA.

Results: The BC-A group presented the higher mean value of BIC (46.43%). The HA/TCP-A group presented the higher mean value of BIC. The porous-hydrophilic surfaces presented better results of BIC when compared to the porous surface in both conditions of defect filling. No statistically significant differences were found among all groups (95% confidence interval and P < .05).

Conclusion: According to histomorphometric analysis, after 60-days in a rabbit model, hydrophilic and hydrophobic surfaces have the same behavior in the presence or absence of HA/TCP.
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http://dx.doi.org/10.1111/cid.12855DOI Listing
December 2019

Strontium enhances proliferation and osteogenic behavior of bone marrow stromal cells of mesenchymal and ectomesenchymal origins in vitro.

Clin Exp Dent Res 2019 10 21;5(5):541-550. Epub 2019 Aug 21.

Department of Dentistry and Oral Health, Faculty of Health Aarhus University Aarhus Denmark.

Obejective: To investigate the effect of increasing Strontium (Sr) concentrations on the growth and osteogenic behavior of human bone marrow stromal cells (BMSCs) from mesenchymal (i.e., fibula) and ectomesenchymal (i.e., mandible) embryonic origins.

Materials And Methods: Fibula and mandible BMSCs were cultured in media without (Ctrl) or with Sr in four diverse concentrations: Sr1, 11.3 × 10 mg/L, human seric physiological level; Sr2, 13 mg/L, human seric level after strontium ranelate treatment; Sr3, 130 mg/L, and Sr4, 360 mg/L. Proliferation rate (1, 3, and 7 days), osteogenic behavior (alkaline phosphatase [ALP] activity, 7 and 14 days; expression of osteogenic genes (ALP, osteopontin, and osteocalcin at 7, 14, and 21 days), and formation of mineralized nodules (14 and 21 days) of the BMSCs were assessed. Data was compared group- and period-wise using analysis of variance tests.

Results: Fibula and mandible BMSCs cultured with Sr4 showed increased proliferation rate, and osteocalcin and osteopontin gene expression together with more evident formation of mineralized nodules, compared all other Sr concentrations. For both cell populations, Sr4 led to lower ALP activity, and ALP gene expression, compared with the other Sr concentrations.

Conclusion: BMSCs from mesenchymal (i.e., fibula) and ectomesenchymal (i.e., mandible) embryonic origins showed increased cellular proliferation and osteogenic behavior when cultured with Sr4, in vitro.
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http://dx.doi.org/10.1002/cre2.221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6820574PMC
October 2019

Impact of movement and motion-artefact correction on image quality and interpretability in CBCT units with aligned and lateral-offset detectors.

Dentomaxillofac Radiol 2020 Jan 24;49(1):20190240. Epub 2019 Sep 24.

Department of Dentistry and Oral Health, Section of Oral Radiology, Aarhus University, Denmark, Europe.

Objectives: To evaluate the impact of movement and motion-artefact correction systems on CBCT image quality and interpretability of simulated diagnostic tasks for aligned and lateral-offset detectors.

Methods: A human skull simulating three diagnostic tasks (implant planning in the anterior maxilla, implant planning in the left-side-mandible and mandibular molar furcation assessment in the right-side-mandible) was mounted on a robot performing six movement types. Four CBCT units were used: Cranex 3Dx (CRA), Ortophos SL (ORT), Promax 3D Mid (PRO), and X1. Protocols were tested with aligned (CRA, ORT, PRO, and X1) and lateral-offset (CRA and PRO) detectors and two motion-artefact correction systems (PRO and X1). Movements were performed at one moment-in-time (t), for units with an aligned detector, and three moments-in-time (t-first-half of the acquisition, t-second-half, t-both) for the units with a lateral-offset detector. 98 volumes were acquired. Images were scored by three observers, blinded to the unit and presence of movement, for motion-related stripe artefacts, overall unsharpness, and interpretability. Fleiss' κ was used to assess interobserver agreement.

Results: Interobserver agreement was substantial for all parameters (0.66-0.68). For aligned detectors, in all diagnostic tasks a motion-artefact correction system influenced image interpretability. For lateral-offset detectors, the interpretability varied according to the unit and moment-in-time, in which the movement was performed. PRO motion-artefact correction system was less effective for the offset detector than its aligned counterpart.

Conclusion: Motion-artefact correction systems enhanced image quality and interpretability for units with aligned detectors but were less effective for those with lateral-offset detectors.
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http://dx.doi.org/10.1259/dmfr.20190240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957066PMC
January 2020

Quantitative assessment of variation in CBCT image technical parameters related to CBCT detector lateral-offset position.

Dentomaxillofac Radiol 2020 Feb 6;49(2):20190077. Epub 2019 Sep 6.

Department of Dentistry and Oral Health, Section of Oral Radiology, Aarhus University, Denmark, Europe.

Objectives: To assess the effect of CBCT detector position (aligned/lateral-offset) on image technical parameters (mean voxel value - MVV, standard deviation of voxel value (SDVV) distribution), comparing peripheral regions of interest (ROIs) to the central ROI in CBCT volumes.

Methods: 40 CBCT volumes of a wax phantom were acquired in six units with aligned and/or lateral-offset detectors: Cranex 3Dx (CRA), Ortophos SL (ORT), Picasso Trio (PIC), Promax 3D Mid (PRO), Scanora 3D (SCA), and X1. Four image-acquisition protocols used an aligned detector, and four a lateral-offset detector. In each volume, 13 ROIs (12 peripheral and 1 central) were evaluated. MVV and SDVV of the peripheral ROI were compared to those of the central ROI in the volume. MVVD (the difference in percentage, between the MVV of a peripheral and the central ROI) was calculated.

Results: For aligned-detectors, MVV increased (ORT and PRO) or decreased (CRA and X1) in the ROIs farther from the centre. For lateral-offset detectors, ROIs farther from the centre showed increased MVV. SDVV for most aligned detectors was lower, the nearer the ROI was to the centre. For lateral-offset detectors, it was lower for the peripheral ROIs, except with PIC. Range for MVVD was -32.8% to 22.8% for units with aligned detectors, and -20.7% to 69.5% for lateral-offset detectors.

Conclusion: Lateral-offset detectors to acquire CBCT images significantly change SDVV distribution within the field-of-view, and lead to MVVD with increased range, compared to aligned detectors. This must be taken in consideration in the clinic, if voxel-value dependent measurements are to be performed.
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http://dx.doi.org/10.1259/dmfr.20190077DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7026930PMC
February 2020

Prevalence and severity of image-stitching artifacts in charge-coupled device-based cephalograms of orthodontic patients.

Oral Surg Oral Med Oral Pathol Oral Radiol 2020 Feb 15;129(2):158-164. Epub 2019 Jul 15.

Oral Radiology, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.

Objectives: The aim of this study was to assess the prevalence and severity of image-stitching artifacts in charge-coupled device (CCD)-based cephalograms and their relationship to patient age.

Study Design: Cephalograms from 200 patients, acquired by using 2 Promax 2-D units (100 images using Dimax-3 [D-3] and 100 using Dimax-4 [D-4] sensors) were examined. Three observers assessed the presence and severity of image-stitching artifacts for stitching line visibility in 3 categories (none or almost invisible, thin, and thin with vertical stripes or thick) and misalignment between the anatomic structure display in 4 categories (none, <1 mm, 1-3 mm, and >3 mm). Severe artifacts were defined as a stitching line that was thin with vertical stripes or thick, and misalignment ≥1 mm. Patients were grouped by age: ≤13, 14-20, and >20 years old. Observer agreement was assessed by using Kappa statistics. Artifact prevalence and severity were calculated for both sensor types. The effect of age on the presence of severe artifacts was assessed.

Results: Stitching lines were observed in 86.7% of D-3 images and 3.3% of D-4 images. Young age had a significant effect on the presence of severe artifacts in D-3 images.

Conclusions: Sensor type and patient age have substantial effects on the prevalence and severity of image-stitching artifacts in CCD-based cephalograms.
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http://dx.doi.org/10.1016/j.oooo.2019.07.004DOI Listing
February 2020

Long-term radiographic assessment of titanium implants installed in maxillary areas grafted with autogenous bone blocks using two predefined sets of success criteria.

Clin Implant Dent Relat Res 2019 Oct 6;21(5):845-852. Epub 2019 Aug 6.

Department of Dentistry and Oral Health, Oral Radiology, Aarhus University, Aarhus, Denmark.

Purpose: Assess the radiographic peri-implant bone loss of implants installed in maxillary areas grafted with autogenous bone and classify the long-term (at least >4 ≤ 6 years) implant success according to two predefined sets of criteria.

Material And Methods: Sixty patients had full maxillary alveolar reconstructions using autogenous bone grafts (iliac crest), and 369 titanium implants were installed. The follow-up protocol was 5 (>4 ≤ 6) years; thereafter only patients who presented significant peri-implant bone loss were followed up to 12 years. The radiographic peri-implant bone level was assessed on panoramic radiographs in relation to the baseline and used to classify the long-term success of the implants according to the predefined success criteria presented by Albrektsson and coworkers (ALB; 1986) and the Pisa Consensus Conference (PCC; 2007).

Results: Fifteen implants were lost over the 12-year follow-up period (two up to >4 ≤ 6 years). Mean radiographic peri-implant bone loss was 2.7 mm at the >4 ≤ 6 years control and 4.2 mm after >11 ≤ 12 years. Different success criteria resulted in different types of prevalence of implants classified as "failures." At >4 ≤ 6 years, 48% of the implants would be "failures" according to ALB, while according to the PCC, only 0.8% would be "failures" and 18.1% would be classified as "compromised survival" and 44.8% as "satisfactory survival."

Conclusions: Mean peri-implant bone loss of implants installed in maxillary areas grafted with autogenous bone blocks was 2.7 mm after >4 ≤ 6 years, and two implants were lost during this period. The use of different success criteria significantly altered the prevalence of implants classified as "failure."
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http://dx.doi.org/10.1111/cid.12827DOI Listing
October 2019

Effect of the software binning and averaging data during microcomputed tomography image acquisition.

Sci Rep 2019 07 22;9(1):10562. Epub 2019 Jul 22.

Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of São Paulo (USP), São Paulo, Brazil.

This study describes the effect of the software binning and data averaging during micro CT volume acquisition, on the assessment of root resorption volumes. The mesial roots (n = 9), after orthodontic tooth movement during 14 days, were scanned, using a micro CT system (9 µm/pixel). All roots were reconstructed and the volumes of the resorption lacunae evaluated. The height and width of the pixels vary according to the parameters (A1, A2, A3, A4, A5, A6, A7, A8, A9) used during the scan. In the root #1 the mean volumes of resorption were similar in A4 and A7; in the root #2 there was no similarity in the mean volumes of resorption in any of the parameters; in root #3 only A4 presented mean volume different from zero (3.05 × 10°). In the root #5, the A1 and A7 presented similar mean volumes and in the A6 and A9 presented near mean volumes. In the root #9 the A1, A4, and A7 presented similar mean volumes and A6 and A9 also had similar mean volumes. Significant difference was detected in the volume of resorption among the roots #2, #5 and #9 (p = 0.04). When analyzing delicate structures such as the roots of rats' molars, the variation of such parameters will significantly influence the results.
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http://dx.doi.org/10.1038/s41598-019-46530-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6646350PMC
July 2019

Addition of zirconium oxide to Biodentine increases radiopacity and does not alter its physicochemical and biological properties.

J Appl Oral Sci 2019 Apr 1;27:e20180429. Epub 2019 Apr 1.

Universidade Estadual Paulista - UNESP, Faculdade de Odontologia de Araraquara, Departamento de Odontologia Restauradora, Araraquara, São Paulo, Brasil.

Objectives: To evaluate the radiopacity of Biodentine (BD) and BD associated with 15% calcium tungstate (BDCaWO4) or zirconium oxide (BDZrO2), by using conventional and digital radiography systems, and their physicochemical and biological properties.

Materials And Methods: Radiopacity was evaluated by taking radiographs of cement specimens (n=8) using occlusal film, photostimulable phosphor plates or digital sensors. Solubility, setting time, pH, cytocompatibility and osteogenic potential were also evaluated. Data were analyzed using one-way ANOVA and Tukey post-test or two-way ANOVA and Bonferroni post-test (α=0.05).

Results: BD radiopacity was lower than 3 mm Al, while BD ZrO2 and BD CaWO4 radiopacity was higher than 3 mm Al in all radiography systems. The cements showed low solubility, except for BDCaWO4. All cements showed alkaline pH and setting time lower than 34 minutes. MTT and NR assays revealed that cements had greater or similar cytocompatibility in comparison with control. The ALP activity in all groups was similar or greater than the control. All cements induced greater production of mineralized nodules than control.

Conclusions: Addition of 15% ZrO2 or CaWO4 was sufficient to increase the radiopacity of BD to values higher than 3 mm Al. BD associated with radiopacifiers showed suitable properties of setting time, pH and solubility, except for BDCaWO4, which showed the highest solubility. All cements had cytocompatibility and potential to induce mineralization in Saos-2 cells. The results showed that adding 15% ZrO2 increases the radiopacity of BD, allowing its radiography detection without altering its physicochemical and biological properties.
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http://dx.doi.org/10.1590/1678-7757-2018-0429DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6442842PMC
April 2019

Influence of residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone.

Clin Oral Implants Res 2019 Apr 18;30(4):315-323. Epub 2019 Mar 18.

Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.

Objective: To evaluate the influence of the posterior residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone.

Material And Methods: Bilateral sinus bone augmentation was performed using anorganic bovine bone in 20 patients with residual bone height <2 mm in at least one site on each side. Trephine samples were removed at the implant insertion site 8 months after the grafting procedure, and histological and histomorphometric analyses were performed to examine the relative amount (%) of new bone, anorganic bovine bone, and soft tissue in the grafted area. Based on cone beam computed tomography evaluation, the sites of implant insertion were classified according to sinus width into narrow, average, and wide, and according to residual bone height into ≤2 and >2 mm.

Results: A total of 146 implants were installed and 103 biopsies were evaluated. New bone formation in sites classified as narrow (69 sites), average (19 sites), and wide (15 sites) was 28.5% ± 9.24, 28.9% ± 8.61, and 30.3% ± 7.80, respectively. The mean posterior maxillary residual bone height was 4.0 ± 2.43 mm, and 26 and 77 sites were classified as ≤2 and >2 mm, respectively. New bone formation was 26.2% ± 9.10 and 29.8% ± 8.67 for residual bone height ≤2 and >2 mm, respectively. The differences were non-significant.

Conclusions: Within the limitations of the present study, posterior residual bone height and sinus width were not factors with influence on new bone formation in sinuses grafted exclusively with anorganic bovine bone after 8 months of healing.
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http://dx.doi.org/10.1111/clr.13417DOI Listing
April 2019

Cone beam computed tomography evaluation of staged lateral ridge augmentation using platelet-rich fibrin or resorbable collagen membranes in a randomized controlled clinical trial.

Clin Oral Implants Res 2019 Mar 25;30(3):277-284. Epub 2019 Feb 25.

Department of Dentistry and Oral Health, Section for Oral Surgery and Oral Pathology, Aarhus University, Aarhus C, Denmark.

Objectives: To evaluate the volumetric changes following lateral alveolar ridge augmentation using autogenous bone graft covered by either a platelet-rich fibrin membrane (test group) or an inorganic bovine bone substitute and a resorbable collagen barrier membrane (control group).

Material And Methods: A total of 27 partially edentulous patients (test n = 14, control n = 13) with the indication for lateral bone block augmentation were included in this randomized, controlled clinical trial. Cone beam computed tomography (CBCT) examination was performed prior to grafting and 2 weeks and 6 months after grafting. The volumetric changes between the various examinations times were evaluated by planimetric measurements on two-dimensional CBCT images of the grafted regions.

Results: The mean bone volumetric loss in the test group was 14.7%, SD ±8.9%, while the mean bone volume loss in the control group was 17.8%, SD ±13.3%. This difference was not significant (p = 0.48). A total of ten patients were operated in the incisor and canine region with a mean bone volume loss of 23.41% SD, ±10.87%, while 17 patients were operated in the premolar region with a mean bone volume loss of 11.89% SD ±9.05%. This difference was significant (p = 0.01).

Conclusion: The test and control group demonstrated no overall difference in volumetric bone changes of the augmented bone at the 6-month follow-up. The second major finding revealed a significantly larger amount of bone resorption in the incisor and canine region than in the premolar region of the maxilla, particularly in the control group.
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http://dx.doi.org/10.1111/clr.13413DOI Listing
March 2019

Comparison of Imaging Softwares for Upper Airway Evaluation: Preliminary Study.

Craniomaxillofac Trauma Reconstr 2018 Dec 25;11(4):273-277. Epub 2017 Aug 25.

Department of Diagnosis and Surgery, Dental School of Araraquara, São Paulo State University, Araraquara, São Paulo, Brazil.

The interest about upper airway evaluation has increased lately. Therefore, many softwares have been developed aiming to improve and facilitate the analysis of airway volume. The objective of this study was to compare two different softwares packages, Mimics and Dolphin, in their accuracy and precision in upper airway space measurements. Preoperative cone beam computed tomography scans of nine nonsyndromic patients submitted to surgically assisted rapid maxillary expansion were included in this study. The imaging exams were converted to DICOM (digital imaging and communications in medicine) files and imported to the softwares. The mean volume for the Dolphin group (G1) was 10.791 cm (SD = 4.269 cm ) and for the Mimics group (G2) was 10.553 cm (SD = 4.564 cm ). There was no statistically significant difference between the two groups (  = 0.105).
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http://dx.doi.org/10.1055/s-0037-1606247DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6224285PMC
December 2018

Effect of ionizing radiation after-therapy interval on bone: histomorphometric and biomechanical characteristics.

Clin Oral Investig 2019 Jun 27;23(6):2785-2793. Epub 2018 Oct 27.

Department of Oral and Maxillofacial Surgery, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4T, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil.

Objectives: This study aimed to evaluate the effects of radiotherapy on biomechanical, histomorphometric, and microstructural characteristics of bone, in diverse periods, compared with intact bone tissue.

Materials And Methods: Eighteen adult male New Zealand rabbits were treated with a single radiation dose of 30 Gy. The animals were randomly divided into six groups: NoIr, control group, no radiation, and five irradiated groups sacrificed after 24 h (Ir24h), 7 (Ir7d), 14 (Ir14d), 21 (Ir21d), and 28 (Ir28d) days. After these periods, the animals were sacrificed and their tibias (n = 6) evaluated using three-point bending test to calculate the ultimate force, work to failure, and bone stiffness. Dynamic indentation test was used to quantify Vickers hardness and elasticity modulus of bone tissue. Micro-CT was used to analyze the cortical volume (CtV), cortical thickness (CtTh), and porosity (Ct.Po). Histomorphometric assessment was based on the lacunarity of bone tissue. Data were analyzed using one-way ANOVA and Kruskal-Wallis tests followed by Tukey, Dunnet, and Dunn's post-tests (P < 0.05).

Results: The ultimate force, work to failure, stiffness, elastic modulus, and Vickers hardness values of irradiated bone were significantly lower that non-irradiated bone. Irradiated bone showed significantly lower CtTh and CtV values and higher CtPo than non-irradiated bone. No significant difference was found for lacunarity between non-irradiated bone and irradiated bone.

Conclusions: Ionizing radiation decreases normal anisotropy on microarchitecture of cortical bone, and increases bone fragility compared with non-irradiated bone. Further, these changes were seen after longer periods (e.g., 14 and 21 days), and not immediately after radiation therapy.

Clinical Relevance: The radiotherapy reduces bone mechanical properties and the normal structure of organic and inorganic bone matrix. For studying the protocols to protect the radiotherapy effect using rabbit model, the use of the sacrificing period between 14 and 21 days is recommended.
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http://dx.doi.org/10.1007/s00784-018-2724-3DOI Listing
June 2019
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