Marcelo Parra

Dr. Marcelo Parra

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 July 2018 in Materials
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Journal Article
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CZConsuelo C. Zumarán
Consuelo C. Zumarán
MPMarcelo Parra
Marcelo Parra
Sergio OlateSergio Olate
Sergio Olate
EFEduardo Fernandez
Eduardo Fernandez
FMFrancisco Munoz
Francisco Munoz
ZHZiyad Haidar
Ziyad Haidar
Platelet-Rich fibrin (PRF) is a three-dimensional (3-D) autogenous biomaterial obtained via simple and rapid centrifugation from the patient’s whole blood samples, without including anti-coagulants, bovine thrombin, additives, or any gelifying agents. At the moment, it is safe to say that in oral and maxillofacial surgery, PRFs (particularly, the pure platelet-rich fibrin or P-PRF and leukocyte and platelet-rich fibrin or L-PRF sub-families) are receiving the most attention, essentially because of their simplicity, cost-effectiveness, and user-friendliness/malleability; they are a fairly new “revolutionary” step in second-generation therapies based on platelet concentration, indeed. Yet, the clinical effectiveness of such surgical adjuvants or regenerative platelet concentrate-based preparations continues to be highly debatable, primarily as a result of preparation protocol variability, limited evidence-based clinical literature, and/or poor understanding of bio-components and clinico-mechanical properties. To provide a practical update on the application of PRFs during oral surgery procedures, this critical review focuses on evidence obtained from human randomized and controlled clinical trials only. The aim is to serve the reader with current information on the clinical potential, limitations, challenges, and prospects of PRFs. Accordingly, reports often associate autologous PRFs with early bone formation and maturation; accelerated soft-tissue healing; and reduced post-surgical edema, pain, and discomfort. An advanced and original tool in regenerative dentistry, PRFs present a strong alternative and presumably cost-effective biomaterial for oro-maxillo-facial tissue (soft and hard) repair and regeneration. Yet, preparation protocols continue to be a source of confusion, thereby requiring revision and standardization. Moreover, to increase the validity, comprehension, and therapeutic potential of the reported findings or observations, a decent analysis of the mechanico-rheological properties, bio-components, and their bioactive function is eagerly needed and awaited; afterwards, the field can progress toward a brand-new era of “super” oro-dental biomaterials and bioscaffolds for use in oral and maxillofacial tissue repair and regeneration, and beyond.

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Sergio OlateSergio Olate
Sergio Olate
VRVíctor Adolfo Ravelo
Víctor Adolfo Ravelo
CHClaudio Huentequeo
Claudio Huentequeo
MPMarcelo Parra
Marcelo Parra
AUAlejandro Unibazo
Alejandro Unibazo
The temporomandibular joint (TMJ) is a complex structure in the cranio-maxillomandibular region. The pathological changes of the joint cause deficiencies at different levels, making its replacement necessary in some cases. The aim of this article is to analyze the current indications, treatment and criteria, and follow-up using a systematic review and case series. A systematic review was carried out, identifying the indications for the use of a customized TMJ prosthesis and evaluating criteria and validation in the international literature. After review and exclusion, 8 articles were included with a minimum follow-up of 12 months. The age of the subjects was between 18 and 47 years old. In 226 patients, 310 TMJ prostheses were installed, 168 bilaterally and 142 unilaterally. In most of the articles, a good condition in the follow-up was observed, with a reduction in pain and better conditions of mandibular movement and function. TMJ prosthesis and replacement is a protocolized, defined, stable, and predictable procedure. Indications and criteria must be evaluated by specialists and patients related to the pathology involved in TMJ deformity or degeneration. Randomized research with an accurate diagnosis and follow-up is necessary to obtain the best indication for this treatment.

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VRVíctor Adolfo Ravelo
Víctor Adolfo Ravelo
GOGabriela Olate
Gabriela Olate
MMMarcio de Moraes
Marcio de Moraes
HGHenry Arturo García Guevara
Henry Arturo García Guevara
MPMarcelo Parra
Marcelo Parra
Sergio OlateSergio Olate
Sergio Olate
The aim of this research was to analyze the facial class, presence of malocclusion, and the mandibular plane and to relate this to the mandibular condyle position. A cross-sectional study in subjects under analysis for orthognathic surgery was done. The mandibular plane, the gonial angle, and the molar class were included to compare the coronal and sagittal position of the condyle and the joint space observed in the CBCT. The measurements were obtained by the same observer at an interval of two weeks. In addition, the Spearman test was performed to determine the correlation using a p value < 0.05 to observe any significant differences. Eighty-nine male and female subjects (18 to 58 years old, 24.6 ± 10.5) were included. In the coronal section, subjects with CIII had a greater mediolateral distance (MLD, p = 0.0001) and greater vertical distance (SID, p = 0.0001) than subjects with CII. In terms of the skeletal class and the mandibular plane, it was observed that subjects in the CII group had a greater mandibular angle (open angle) (p = 0.04) than the CII group and was related to the anterior position of the condyle. The most anterior condylar position was observed in the CII group (p = 0.03), whereas a posterior condylar position was significant in CIII subjects (p = 0.03). We can conclude that the sagittal position of the TMJ was related to the mandibular plane and the skeletal class showing a higher mandibular angle and most anterior position of the condyle in CII subjects and a lower mandibular angle and most posterior position of the condyle in CIII subjects. The implications for surgical treatment have to be considered.

27 March 2024 in Bioengineering
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SSSogand Schafer
Sogand Schafer
TSTina Swain
Tina Swain
MPMarcelo Parra
Marcelo Parra
BSBlaire Slavin
Blaire Slavin
NMNicholas Alexander Mirsky
Nicholas Alexander Mirsky
PCPaulo G. Coelho
Paulo G. Coelho
The energy state of endosteal implants is dependent on the material, manufacturing technique, cleaning procedure, sterilization method, and surgical manipulation. An implant surface carrying a positive charge renders hydrophilic properties, thereby facilitating the absorption of vital plasma proteins crucial for osteogenic interactions. Techniques to control the surface charge involve processes like oxidation, chemical and topographical adjustments as well as the application of nonthermal plasma (NTP) treatment. NTP at atmospheric pressure and at room temperature can induce chemical and/or physical reactions that enhance wettability through surface energy changes. NTP has thus been used to modify the oxide layer of endosteal implants that interface with adjacent tissue cells and proteins. Results have indicated that if applied prior to implantation, NTP strengthens the interaction with surrounding hard tissue structures during the critical phases of early healing, thereby promoting rapid bone formation. Also, during this time period, NTP has been found to result in enhanced biomechanical fixation. As such, the application of NTP may serve as a practical and reliable method to improve healing outcomes. This review aims to provide an in-depth exploration of the parameters to be considered in the application of NTP on endosteal implants. In addition, the short- and long-term effects of NTP on osseointegration are addressed, as well as recent advances in the utilization of NTP in the treatment of periodontal disease.

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QEQuinn Ehlen
Quinn Ehlen
NMNicholas Alexander Mirsky
Nicholas Alexander Mirsky
BSBlaire Slavin
Blaire Slavin
MPMarcelo Parra
Marcelo Parra
VNVasudev Vivekanand Nayak
Vasudev Vivekanand Nayak
PCPaulo G. Coelho
Paulo G. Coelho
Bone regeneration remains a significant clinical challenge, often necessitating surgical approaches when healing bone defects and fracture nonunions. Within this context, the modulation of adenosine signaling pathways has emerged as a promising therapeutic option, encouraging osteoblast activation and tempering osteoclast differentiation. A literature review of the PubMed database with relevant keywords was conducted. The search criteria involved in vitro or in vivo models, with clear methodological descriptions. Only studies that included the use of indirect adenosine agonists, looking at the effects of bone regeneration, were considered relevant according to the eligibility criteria. A total of 29 articles were identified which met the inclusion and exclusion criteria, and they were reviewed to highlight the preclinical translation of adenosine agonists. While preclinical studies demonstrate the therapeutic potential of adenosine signaling in bone regeneration, its clinical application remains unrealized, underscoring the need for further clinical trials. To date, only large, preclinical animal models using indirect adenosine agonists have been successful in stimulating bone regeneration. The adenosine receptors (A1, A2A, A2B, and A3) stimulate various pathways, inducing different cellular responses. Specifically, indirect adenosine agonists act to increase the extracellular concentration of adenosine, subsequently agonizing the respective adenosine receptors. The agonism of each receptor is dependent on its expression on the cell surface, the extracellular concentration of adenosine, and its affinity for adenosine. This comprehensive review analyzed the multitude of indirect agonists currently being studied preclinically for bone regeneration, discussing the mechanisms of each agonist, their cellular responses in vitro, and their effects on bone formation in vivo.

12 February 2026 in Journal of Clinical Medicine
Verified
Journal Article
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Sergio OlateSergio Olate
Sergio Olate
VRVíctor Adolfo Ravelo
Víctor Adolfo Ravelo
HGHenry Arturo García Guevara
Henry Arturo García Guevara
Roberto SaccoRoberto Sacco
Roberto Sacco
MPMarcelo Parra
Marcelo Parra
MMMarcio de Moraes
Marcio de Moraes
Background: Mandibular advancement is a commonly performed surgical procedure for the treatment of mandibular retrognathia and Class II dentofacial deformities; however, large advancements impose increased mechanical demands on fixation systems. Despite the availability of various fixation strategies, standard straight plate systems remain widely used worldwide due to their availability, cost-effectiveness, and clinical familiarity. Continuous biomechanical evaluation of these systems is therefore required to optimize stability and performance under demanding conditions. Objectives: The aim of this study was to evaluate the influence of plate design, plate thickness, and fixation architecture on the mechanical stability of mandibular advancement using finite element analysis. Methods: A three-dimensional finite element model simulating a unilateral mandibular osteotomy with a 10 mm gap was generated as mandibular advancement was developed. Fifteen fixation configurations were analyzed, including variations in plate design (simple and reinforced plates with partial or total inferior mesh extension), plate thickness (0.8 mm and 1.0 mm), and fixation architecture using independent plate systems (LN) or integrated fixation systems (FM). A vertical load was applied to the lower central incisor to simulate functional loading. Outcome measures included global equivalent stress considering screws and plate, equivalent stress within the plate, and global deformation of the fixation system. Results: The analyses demonstrated distinct mechanical behaviors among the evaluated configurations. Differences in stress distribution and deformation were observed according to plate design, thickness, and fixation architecture. Reinforced designs, increased plate thickness, and integrated fixation systems showed reduced deformation and more favorable stress distribution when compared with simple plate configurations. Conclusions: Plate design, thickness, and fixation architecture influenced the mechanical stability of mandibular advancement, supporting the importance of biomechanical optimization of standard fixation systems, particularly in large mandibular advancements.