Maxillary Impaction Does Not Negatively Affect the Nasal Airway: A Systematic Review With Meta-Analysis.

PURPOSE: Le Fort I maxillary impaction is an orthognathic surgical procedure to reposition the maxillary complex superiorly. The objective of this study is to investigate if maxillary impaction negatively affects the nasal airway. METHODS: A systematic review with meta-analysis was performed to investigate the effects of maxillary impaction on the nasal cavity. PubMed, Embase, and Cochrane Library databases were accessed. Observational studies, nonrandomized, and randomized controlled trials were included if Le Fort 1 maxillary impaction and nasal airway outcomes assessments were performed. Studies were excluded if maxillary impaction or nasal airway outcome assessment was not performed or if the study included patients with cleft or craniofacial syndromes, previous nasal surgeries, or active respiratory tract. The demographic data, study methodology, magnitude of maxillary impaction, and outcomes related to the nasal airway were collected. These outcomes includes anatomical changes (evaluated by rhinoscopy, acoustic rhinometry, and computed tomography), changes to nasal airflow and resistance (evaluated by rhinomanometry) and changes to quality of life. RESULTS: The search yielded 7517 studies. Ten studies were included after the application of the selection criteria. A total of 126 patients underwent pure maxillary impaction, 97 underwent maxillary impaction and advancement, and 12 had impaction with setback. Despite that maxillary impactions decreased the nasal cavity volume by +21.7%, the cross-sectional area of the narrowest parts of the cavity was only reduced by -8.4%. Maxillary impactions generally increases the nasal airflow (+12.6%) while reducing nasal resistance (-20.2%). Rhinoscopies also showed a reduction in nasal obstruction. CONCLUSION: Maxillary impaction did not negatively affect the nasal airway. The surgeries did not lead to the reduction of the cross-sectional area at the strictures of the nasal cavities. The nasal airflow and resistance was not decreased and increased, respectively. The quality of life of the patients was also not shown to have worsened.

The effects of VY closure on lip morphology after Le Fort I maxillary advancement: A systematic review.

VY closure of the Le Fort 1 incision may commonly be indicated to mitigate the lip shortening effects of maxillary advancement. The objective of this systematic review was to investigate if VY closure prevents lip shortening when compared with conventional continuous closure (CS) methods, in patients who underwent le fort 1 maxillary advancement. PubMed, Embase, and Cochrane Library databases were accessed. Hand searching was also performed. Observational studies, non-randomised and randomized controlled trials were included if Le Fort 1 maxillary advancement was performed to correct a dentofacial deformity. Comparisons were made between VY and CS, and morphological changes to the upper lip were evaluated. The demographic data, study methodology, magnitude of maxillary movements and outcomes related to the lip morphology (length, vermillion exposure, thickness and angulation) were extracted. The search yielded 487 articles. Six studies were included after the application of the selection criteria. A total of 100 and 94 patients received CS and VY respectively. VY was not found to reliably prevent lip shortening. VY was more likely to mitigate lip shortening when there is a large maxillary advancement. It was consistent for a protrusive or "rolled-out" lip morphology to occur after a VY closure. This was demonstrated by the increase in lip vermillion exposure, thickness, and angulation. VY closure was a useful adjunctive technique in patients undergoing large maxillary advancements to mitigate the lip shortening effect from the procedure. Surgeons who employ this technique must also be aware of the consequence of a more protrusive lip with increased vermillion exposure and assess if this would be aesthetically desirable for the individual patient.

Mandibular asymmetry: Is there a difference in the bone and soft tissue thickness between both sides?

OBJECTIVE: The asymmetric mandible presents the clinician with unique anatomic challenges in orthognathic surgery correction. This study aims to investigate these characteristics of the asymmetric mandible: mandible bone thickness, soft tissue thickness, and the proximity of the bone cortex to the inferior alveolar nerve (IAN) canal. STUDY DESIGN: Three-dimensional virtual models were created of 35 participants of Asian descent with mandibular asymmetry. Mandibular bone thicknesses and soft tissue thicknesses were measured at certain landmarks. Statistical analysis of the thicknesses of both sides of the mandible was performed. Comparison of thicknesses between patients with minor and major asymmetry were also performed. RESULTS: The bone was significantly thinner at the longer side at all 4 mandible landmarks (P < .001). The bone lateral to the IAN was significantly thinner at the longer side, as well (P < .001). The soft tissue thickness did not differ significantly across sides, except at 1 landmark. These findings were even more exaggerated in the major asymmetry group. CONCLUSIONS: The longer side of the asymmetric mandible bone was thinner, and the bone lateral to the IAN was also thinner as a result. This asymmetric thinness was exaggerated in patients with severe asymmetry, which may predispose the longer side to IAN injury and unfavorable fractures. The differences in bone thickness in the asymmetric mandible may also result in residual postoperative asymmetry.

Should we stop dual anti-platelet therapy for dental extractions? An umbrella review for this dental dilemma.

OBJECTIVES: Dual Anti-platelet Therapy (DAPT) are prescribed to patients who had or are at risk of cerebrovascular or cardiovascular ischemic events. This umbrella review appraises existing systematic reviews on the risk of bleeding related complications during and after dental extractions for patients on DAPT. STUDY DATA AND SOURCES: This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered to the PROSPERO (International prospective register of systematic reviews) database. A systematic electronic literature search was conducted according to the PRISMA guidelines, via PubMed, Ovid, Cochrane and Embase. STUDY SELECTION: Four systematic reviews met the inclusion criteria and were included the analysis. They show DAPT increases the risk of bleeding related complications after dental extractions, but the differences may not be clinically significant as local haemostatic measures were adequate in controlling bleeding. CONCLUSION: Despite the increased risk of bleeding after dental extractions in patients on DAPT, it may not be necessary to interrupt the anti-platelet therapy. Local haemostatic agents may be sufficient in controlling both the primary or secondary bleeding. On the other hand, the complications of discontinuing DAPT may be more severe and fatal.

Preservation of the superficial temporal artery during resection of a pseudoaneurysm: A case report and review of the literature.

The superficial temporal artery (STA) is a structure that is particularly vulnerable to injury, given its prominent location in the head and neck region. Pseudoaneurysms of this artery may be encountered during the management of maxillofacial trauma. This article presents a review of the relevant literature on this topic. One of the common surgical interventions includes ligation of the entire feeding artery, which compromises the corresponding blood supply. Preservation of the main trunk of the STA can be achieved in certain cases; one such case is detailed in this report.

Bioactivity, physical and chemical properties of MTA mixed with propylene glycol.

OBJECTIVE: To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water. MATERIAL AND METHODS: White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey's post-hoc analysis (a=0.05). RESULTS: The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0. CONCLUSION: Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA.

Bioactivity, physical and chemical properties of MTA mixed with propylene glycol

AbstractObjective To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water.Material and Methods White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey’s post-hoc analysis (a=0.05).Results The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0.Conclusion Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA.