Roberto Sacco

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.

Objectives: This study aims to describe and analyze the indications and clinical results of total TMJ replacement in participants with degenerative and/or inflammatory joint diseases, defining patient and intervention conditions. Methods: A systematic review was conducted according to the Cochrane Handbook for Systematic Reviews of Intervention and reported according to the PRISMA Items update. The search strategy was from 1997 to July 2024 in Pubmed, Embase, Scopus, and Web of Science. A search for gray literature was conducted in the databases Google Scholar and Open Access Theses and Dissertations (OATD), and there were no limitations on the language or study design. We incorporated studies involving human patients over 15 years of age with degenerative and/or inflammatory joint conditions who underwent joint prosthesis replacement, either concurrently or separately from orthognathic surgery, as an initial intervention or after prosthesis installation. Participants with a postoperative follow-up of 12 months or longer were included. A risk of bias analysis was performed for non-randomized studies using the ROBINS-I tool, and GRADE profiler (GRADEpro) software was used to assess the quality of evidence and synthesize the data. Results: All the selected studies performed postoperative follow-up with quantitative and qualitative parameters; 10 performed a follow-up of 2 to 5 years. The indication for joint prosthesis replacement due to system failure was only 4.07%. Concerning diagnoses, 579 presented degenerative and/or inflammatory joint diseases, with osteoarthritis being the most frequent, followed by osteoarthrosis, juvenile idiopathic arthritis, and rheumatoid arthritis. The maximum mouth opening of the participants with TMJ disease presented an average of 24.32 ± 5.8 mm with a range of 18 to 36.4 mm. Of the 579 participants, the studies mention that they presented a soft to liquid diet and pain associated with decreased mandibular functionality. Conclusions: A total of 76.18% of the participants presented a range of moderate to severe pain associated with a decrease in functionality and, after joint replacement, all participants mentioned a decrease in pain or absence of pain, a change in diet by incorporating solid foods, and an increase in opening with an average of 40.74 ± 3.1 mm. Total joint replacement shows favorable long-term results. It is not possible to identify the best time to perform joint replacement surgery, considering the time since diagnosis of the disease, the time since the start of non-surgical treatment, or the number of previous surgeries.

Background and Objectives: This study investigates the efficacy of 4% articaine buccal infiltration in patients with mandibular molar irreversible pulpitis. The goal is to understand the anatomical factors contributing to articaine’s success in mandibular infiltrations. Materials and Methods: A randomized controlled trial was conducted with 50 patients diagnosed with symptomatic irreversible pulpitis in mandibular molars. Patients were divided into two groups: 4% articaine buccal infiltration (n = 30) and 2% lidocaine nerve block (n = 20). Pain was assessed using visual analog scales (VASs) before diagnosis, after thermal pulp sensitivity testing, and 5 and 10 min post-anesthetic application. Cone beam computed tomography (CBCT) was used to measure mandibular bone parameters. Results: The success rate for articaine buccal infiltration was 36.55%, with no significant difference between the efficacy in the first and second molars. CBCT measurements indicated no significant influence of buccal cortical bone thickness or distance from the mental foramen on anesthetic efficacy. However, articaine administration achieved anesthesia in some cases where lidocaine did not. Conclusions: Anatomical structures such as cortical bone thickness and distance from the mental foramen do not significantly influence the anesthetic efficacy of articaine in mandibular posterior infiltration for irreversible pulpitis treatment. These findings suggest that factors other than anatomical variations contribute to articaine’s superior performance in some clinical scenarios.

The control of infectious diseases caused by biofilms is a continuing challenge for researchers due to the complexity of their microbial structures and therapeutic implications. Photodynamic therapy as an adjunctive anti-infective treatment has been described as a possible valid approach but has not been tested in polymicrobial biofilm models. This study evaluated the effect of photodynamic therapy in vitro with methylene blue (MB) 0.01% and red LEDs (λ = 660 nm, power density ≈ 330 mW/cm², 2 mm distance from culture) on the metabolic activity and composition of a multispecies subgingival biofilm. Test Groups LED and MB + LED showed a more significant reduction in metabolic activity than the non-LED application group (~50 and 55%, respectively). Groups LED and MB equally affected (more than 80%) the total bacterial count in biofilms. No differences were noted in the bacterial biofilm composition between the groups. In vitro LED alone or the MB + LED combination reduced the metabolic activity of bacteria in polymicrobial biofilms and the total subgingival biofilm count.

Dehiscence in surgeries involving membranes often leads to bacterial contamination, hindering the healing process. This study assessed bacterial colonization on various membrane materials. Polydioxanone (PDO) membranes, with thicknesses of 0.5 mm and 1 mm, and a collagen membrane were examined. Packages containing polystyrene pins were crafted using these membranes, attached to 24-well plates, and exposed to oral bacteria from supra and subgingival biofilm. After a week’s anaerobic incubation, biofilm formation was evaluated using the DNA–DNA hybridization test. Statistical analysis employed the Kruskal–Wallis test with Dunn’s post hoc test. The biofilm on the polystyrene pins covered by the 0.5 mm PDO membrane showed a higher count of certain pathogens. The collagen membrane had a greater total biofilm count on its inner surface compared to both PDO membranes. The external collagen membrane face had a higher total biofilm count than the 0.5 mm PDO membrane. Furthermore, the 1 mm PDO membrane exhibited a greater count of specific pathogens than its 0.5 mm counterpart. In conclusion, the collagen membrane presented more biofilm and pathogens both internally and on its inner surface.

Orthognathic surgery is indicated to modify the position of the maxillomandibular structure; changes in the mandibular position after osteotomy can be related to changes in the position of the mandibular condyle in the articular fossa. The aim of this study was to determine changes produced in the mandibular condyle 6 months after orthognathic surgery. A cross-sectional study was conducted that included subjects who had undergone bimaxillary orthognathic surgery to treat dentofacial deformity of Angle class II (group CII) or Angle class III (group CIII). Standardized images were taken using cone-beam computed tomography 21 days before surgery and 6 months after surgery; measurement scales were used to identify the condylar position and its relations with the anterior, superior, and posterior joint spaces. The results were analyzed using the Shapiro–Wilk and Student’s t-tests, while considering a value of p < 0.05 as indicating a significant difference. Fifty-two joints from 26 patients, with an average age of 27.9 years (±10.81), were analyzed. All subjects in both group CII and group CIII showed a significant change in the anterior, superior, and posterior joint spaces. However, postoperative changes in the position of the condyle in the articular fossa were not significant in the anteroposterior analysis. We conclude that orthognathic surgery causes changes in the sagittal position of the mandibular condyle in subjects with mandibular retrognathism and prognathism.

The study aimed to assess the efficacy of using Raloxifene with ultrasonic processing to enhance Bio-Oss^®, a bone graft substitute, for maxillary sinus bone height reconstruction. A total of 24 rabbit maxillary sinuses were distributed into three groups, each receiving different treatments: Bio-Oss^® only, sonicated Bio-Oss, and sonicated Bio-Oss^® with Raloxifene. Surgical procedures and subsequent histomorphometric and immunohistochemistry analyses were conducted to evaluate the bone formation, connective tissue, and remaining biomaterial, as well as the osteoblastic differentiation and maturation of collagen fibers. Results indicated that the sonicated Bio-Oss^® and Bio-Oss^® groups showed similar histological behavior and bone formation, but the Raloxifene group displayed inflammatory infiltrate, low bone formation, and disorganized connective tissue. The statistical analysis confirmed significant differences between the groups in terms of bone formation, connective tissue, and remaining biomaterial. In conclusion, the study found that while sonicated Bio-Oss^® performed comparably to Bio-Oss^® alone, the addition of Raloxifene led to an unexpected delay in bone repair. The findings stress the importance of histological evaluation for accurate bone repair assessment and the necessity for further investigation into the local application of Raloxifene. Future research may focus on optimizing bone substitutes with growth factors to improve bone repair.

Objectives This study aimed to compare the reconstruction with type 2.4 and three-dimensional (3D) grid plates relating the areas of weakness to anatomical regions of force incidence in atrophic mandibles with and without segmentation using finite element analysis (FEA). Materials and methods Strength and force quality in the mandible were also determined. The atrophic mandible models with and without segmentation were divided into four groups, and the behavior of each plate was analyzed using finite element analysis. In the atrophic mandible without segmentation using the type 2.4 reconstruction plate, the highest stress concentration in the plate was observed in the posterior region of the mandibular body and in the grid type 3D reconstruction plate was observed in the mandibular angle. Results In the segmented atrophic mandible with the 2.4 reconstruction plate, higher stress concentration was observed in the mandibular segment defect. Analysis of the 3D grid-like reconstruction plate revealed that the geometry of the plate conferred greater stiffness to the assembly, as the most significant stress concentration was observed at the mandibular angle. Conclusion The width of the plate design may influence the strength, not the thickness.

Background and objectives: Although it is very uncommon, medication-induced osteonecrosis of the jaw (also known as MRONJ) can have serious consequences. Traditionally, this adverse event has been recognised in patients who were treated with bisphosphonate (BP) drugs. Nevertheless, in recent years, it has been established that individuals having treatment with various types of medications, such as a receptor activator of nuclear factor kappa-Β ligand inhibitor (denosumab) and antiangiogenic agents, have had the same issue. The purpose of this research is to determine if the application of human amniotic membrane (hAM) may be used as a therapy for MRONJ. Material and Methods: A multi-source database (MEDLINE, EMBASE, AMED, and CENTRAL) systematic search was performed. The major objective of this study is to obtain an understanding of the efficacy of hAM when it is employed as a treatment modality for MRONJ. The protocol of this review was registered in the INPLASY register under the number NPLASY202330010. Results: The authors were able to include a total of five studies for the quality analysis, whereas for the quantity evaluation, only four studies were eligible. A total of 91 patients were considered for the investigation. After treatment with human amniotic membrane (hAM), a recurrence of osteonecrosis was observed in n = 6 cases (8.8%). The combined efficacy of surgical therapy and the use of hAM resulted in an overall success rate of 91.2%. Intraoperative complications were only documented in one article, and they were mostly caused by the positioning of the hAM, which led to wound breakdown at the surgical site. Conclusions: Based on the small amount of data and low-quality research included in this study, using human amniotic membranes to treat MRONJ might represent a feasible option. Nevertheless, further studies with a wider patient population are required to understand the long-term impacts.

Facial asymmetry associated with unilateral condylar hyperplasia (UCH) is a rare disease. The aim of this study was to evaluate the clinical conditions of progressive facial asymmetry in young subjects treated with high condylectomy. A retrospective study was performed including nine subjects diagnosed with UCH type 1B and progressive facial asymmetry around 12 years old with an upper canine progressing towards dental occlusion. After an analysis and a decision of treatment, orthodontics began one to two weeks prior to the condylectomy (with a mean vertical reduction of 4.83 ± 0.44 mm). Facial and dental asymmetry, dental occlusion, TMJ status and an open/closing mouth were analyzed before surgery and in the final stage of treatment, almost 3 years after surgery. Statistical analyses were performed using the Shapiro–Wilk test and a Student’s t-test considering a p value of p = 0.8), whereas the non-operated condyle showed greater height increase with an average of 3.88 mm of vertical growth (p = 0.0001). This indicated that the non-operated condyle remained steady and that the operative condyle did not register significant growth. In terms of facial asymmetry in the preoperative stage, a chin deviation of 7.55 mm (±2.57 mm) was observed; in the final stage, there was a significant reduction in the chin deviation with an average of 1.55 mm (±1.26 mm) (p = 0.0001). Given the small number of patients in the sample, we can conclude that high condylectomy (approx. 5 mm), if performed early, especially in the mixed-dentition stage before full canine eruption, is beneficial for the early resolution of asymmetry and thus the avoidance of future orthognathic surgery. However, further follow-up until the end of facial growth is required.