Comparison of frictional forces during the closure of extraction spaces in passive self-ligating brackets and conventionally ligated brackets using the finite element method

BACKGROUND

This study compared the frictional force resulting from the bracket/archwire interface and the stress at the root/periodontal ligament/bone interface, between passive self-ligating brackets and conventionally ligated brackets, during the space closure stage.

MATERIAL AND METHODS

A cone beam tomography was taken to a female patient that required extraction of upper first premolars and passive self-ligating system; three months after its activation, a cone beam tomography was taken again. The designs of the maxillary bone and the entire system were possible through tomography images and stereomicroscopic photographs. Validation of the Finite Element Method (FEM) was achieved comparing the amount of movement seen through tomography images and the FEM. Space closure was simulated for each system through the FEM and a comparison was made between the frictional force at the bracket/archwire interface, and the root/periodontal ligament/bone interface.

RESULTS

The most significant representation of frictional force at bracket/archwire interface and bone stress was found at the conventionally ligated system, while the passive self-ligating system accounted for the highest distribution of stress over the root.

CONCLUSIONS

The FEM is an accurate tool used to quantify frictional force and stress concentration during the orthodontic closure. The passive self-ligating system was seen less frictional during the closure state compared to conventional brackets. Key words:Friction, orthodontic bracket, finite element analysis.

The Potential Clinical Applications of a Microfluidic Lab-on-a-Chip for the Identification and Antibiotic Susceptibility Testing of Enterococcus faecalis-Associated Endodontic Infections: A Systematic Review

This systematic review evaluated the potential clinical use of microfluidic lab-on-a-chip (LOC) technology in the identification and antibiotic susceptibility testing of E. faecalis in endodontic infections. The search methodology employed in this review adhered to the PRISMA guidelines. Multiple scientific databases, including PubMed/MEDLINE, SCOPUS, and SCIELO, were utilized, along with exploration of grey literature sources. Up to September 2023, these resources were searched using specific keywords and MeSH terms. An initial comprehensive search yielded 202 articles. Ultimately, this systematic review incorporated 12 studies. Out of these, seven aimed to identify E. faecalis, while the remaining five evaluated its susceptibility to different antibiotics. All studies observed that the newly developed microfluidic chip significantly reduces detection time compared to traditional methods. This enhanced speed is accompanied by a high degree of accuracy, efficiency, and sensitivity. Most research findings indicated that the entire process took anywhere from less than an hour to five hours. It is important to note that this approach bypasses the need for minimum inhibitory concentration measurements, as it does not rely on traditional methodologies. Microfluidic devices enable the rapid identification and accurate antimicrobial susceptibility testing of E. faecalis, which are crucial for timely diagnosis and treatment in endodontic infections.

Bacterial resistance to antiseptics used in dentistry: A systematic scoping review of randomized clinical trials

OBJECTIVES

To evaluate the prevalence and proportions of bacteria resistant to antiseptics used in dentistry.

METHODS

A review of randomized clinical trials (RCTs) was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping reviews involving different databases. MeSH terms and keywords were provided to examine only RCTs with antiseptic-resistant results.

RESULTS

Five RCTs were included. These investigations analysed 442 patients. Concerning the prevalence and proportion of species resistant to antiseptics, it was found that the chlorhexidine group showed a statistically significant increase in Streptococcus mutans and Lactobacillus acidophilus counts indicating bacterial resistance (p < 0.001). Moreover, Veillonella species showed resistance to triclosan at the commencement and during the RCTs, and a slight increase in the proportion of resistant strains was observed. Porphyromonas gingivalis, Staphylococcus aureus, and Pseudomonas aeruginosa did not show resistance to cetylpyridinium chloride. Similarly, it was no observed resistance to medicinal herbal plant formulations.

CONCLUSIONS

Resistance of S. mutans and L. acidophilus to chlorhexidine was observed, this resistance increased during the follow-up period. Similarly, although in a slight proportion, an increase in the resistance of Veillonella spp. to triclosan during the study period was also described. No microorganisms resistance was observed to any of the other antiseptics studied.

Antibiotic Resistance in Patients with Peri-Implantitis: A Systematic Scoping Review

The implementation of adjunctive antibiotics has been recommended for the therapy of peri-implantitis (PI). In this review, antibiotic resistance patterns in PI patients were assessed. A systematic scoping review of observational studies and trials was established in conjunction with the PRISMA extension for scoping reviews. The SCOPUS, PubMed/MEDLINE, EMBASE, SCIELO, Web of Science, and LILACS databases were reviewed along with the gray literature. The primary electronic examination produced 139 investigations. Finally, four observational studies met the selection criteria. These studies evaluated 214 implants in 168 patients. Porphyromonas gingivalis and Fusobacterium nucleatum mainly presented high resistance to tetracycline, metronidazole, and erythromycin in PI patients. Similarly, Aggregatibacter actinomycetemcomitans was also highly resistant to clindamycin and doxycycline. Other microorganisms such as Tannerella forsythia, Parvimonas micra, and Prevotella intermedia/nigrescens also presented significant levels of resistance to other antibiotics including amoxicillin, azithromycin, and moxifloxacin. However, most microorganisms did not show resistance to the combination amoxicillin metronidazole. Although the management of adjunctive antimicrobials in the therapy of PI is controversial, in this review, the resistance of relevant microorganisms to antibiotics used to treat PI, and usually prescribed in dentistry, was observed. Clinicians should consider the antibiotic resistance demonstrated in the treatment of PI patients and its public health consequences.

Efficacy of microchips and 3D sensors for orthodontic force measurement: A systematic review of in vitro studies

OBJECTIVE

To evaluate the efficacy of microchips and 3D microsensors in the measurement of orthodontic forces.

METHODS

Through September 2023, comprehensive searches were conducted on PubMed/MEDLINE, SCOPUS and SCIELO without restrictions.

RESULTS

After removing duplicate entries and applying the eligibility criteria, 23 studies were included for analysis. All the studies were conducted in vitro, and slightly more than half of them were centred on evaluating orthodontic forces exerted by aligners. Eight utilized microchips as measurement tools, while the remaining studies made use of 3D microsensors for their assessments. In the context of fixed appliances, key findings included a high level of agreement in 3-dimensional orthodontic force detection between simulation results and actual applied forces. Incorporating critical force-moment combinations during smart bracket calibration reduced measurement errors for most components. Translational tooth movement revealed a moment-to-force ratio, aligning with the bracket's centre of resistance. The primary findings in relation to aligners revealed several significant factors affecting the forces exerted by them. Notably, the foil thickness and staging were found to have a considerable impact on these forces, with optimal force transmission occurring at a layer height of 150 μm. Furthermore, the type of material used in 3D-printing aligners influenced the force levels, with attachments proving effective in generating extrusive forces. Deliberate adjustments in aligner thickness were observed to alter the forces and moments generated.

CONCLUSIONS

Microchips and 3D sensors provide precise and quantitative measurements of orthodontic forces in in vitro studies, enabling accurate monitoring and control of tooth movement.

Benefits of adjunctive moxifloxacin in generalized aggressive periodontitis: a subgroup analyses in Aggregatibacter actinomycetemcomitans-positive/negative patients from a clinical trial

AIM

The aim of the present study was to evaluate the influence of the baseline detection of Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) on the clinical outcomes of moxifloxacin (MOX) as an adjunct to full-mouth scaling and root planing (SRP) in generalized aggressive periodontitis (GAgP).

METHODS

Forty patients were randomly distributed to two therapy protocols: SRP + placebo or SRP combined with MOX. A. actinomycetemcomitans was detected using culture methods. The significance of the treatment option (MOX or SRP + placebo) on the dependent variables (probing depth [PD] and clinical attachment level [CAL]), considering the interaction with the baseline detection of A. actinomycetemcomitans, was estimated.

RESULTS

MOX therapy led to a higher significant PD reduction and CAL gain in A. actinomycetemcomitans-positive patients at baseline. In A. actinomycetemcomitans-positive patients, the reduction of sites ≥5 mm was higher in the MOX group. A. actinomycetemcomitans was not present in sites with PD ≥6 mm in the MOX group. The interactions of A. actinomycetemcomitans and MOX were significantly associated with CAL gain and PD reduction at 6 months.

CONCLUSIONS

Adjunctive MOX trended toward better clinical responses in A. actinomycetemcomitans-positive patients at baseline. These results suggest that A. actinomycetemcomitans at baseline might modify the effect of adjunctive MOX in GAgP.

A Multilevel Approach on Self-Reported Dental Caries in Subjects of Minority Ethnic Groups: A Cross-Sectional Study of 6440 Adults

Regional contextual factors and dental caries using multilevel modeling related to adults in minority ethnic groups have been scantily explored. The influence of the socioeconomic context on self-reported dental caries (SRDC) in individuals of minority ethnic groups (IEG) in Colombia was studied. Data from the 2007 National Public Health Survey were collected in 34,843 participants of the population. The influence of different factors on SRDC in IEG was investigated with logistic and multilevel regression analyses. A total of 6440 individuals belonged to an ethnic group. Multilevel analysis showed a significant variance in SRDC that was smaller in IEG level than between states. Multilevel multivariate analysis also associated SRDC with increasing age, lower education level, last dental visit >1 year, unmet dental need and low Gross Domestic Product (GDP). Minority ethnic groups were at risk to report higher dental caries, where low GDP was an important variable to be considered.

Human papilloma virus genotypes in dysplasia and epithelial hyperplasia of oral cavity using the luminex xmap technology. A multicenter study

BACKGROUND

Oral cancer associated with high risk (HPV-HR) human papilloma virus (HPV) has been increasing. HPV-HR has been associated with epithelial dysplasia, however, little information exists on its frequency in epithelial hyperplasia lesions. The aim of this study is to compare HPV genotypes in dysplastic and hyperplastic lesions of oral cavity.

MATERIAL AND METHODS

Two hundred and fifty oral lesions: 131 dysplasia and 119 hyperplasia from two regions of Colombia were evaluated. One hundred seventy-four coming from urban area and 104 from a high risk population to oral cancer from a rural area. HPV was identified by qPCR and Twenty-four HPVs genotypes were evaluated by Luminex® technology. Logistic regressions were performed to establish the associations between HPV infections with oral dysplasia.

RESULTS

Twenty-eight percent (70/250) of the samples were positives for any HPV and HPV-HRs were more frequently than low risk HPVs. HPV-16 was the most detected genotype (16%) followed by HPV-31, 53, 18 and 45. HPV, HPV-HRs and HPV-16 were only associated with dysplasia in urban area; OR 3.28 (CI 95% 1.49-7.17), OR 7.94 (CI 95% 2.97-21.2) and OR 5.90 (CI 95% 2.05-17). Individuals in rural area showed more HPV and HPV-HRs infection in hyperplasic lesions than urban population. The majority of HPV+ lesions had multi-type of HPV (52/70) and the urban individuals showed more genotypes than rural population.

CONCLUSIONS

HPV-.HRs are frequently found in hyperplastic and dysplastic epithelial lesions. HPV-HRs and HPV-16 were associated with dysplasia in urban population. Rural high risk population and urban population differ in the frequency and variety of HPV genotypes.

Kounis Syndrome Secondary to Laxative Administration

Kounis syndrome (KS) is defined as an acute coronary syndrome triggered by the release of inflammatory mediators after an allergic attack. It usually occurs secondary to allergic injuries from foods, medications, and insect bites. However, there are no known reports of KS secondary to the intake of laxatives. This article reports the case of a 43-year-old woman who, after ingesting a dose of sodium phosphate monobasic/sodium phosphate dibasic, presented a maculopapular rash on the trunk and extremities. The electrocardiogram showed ST depression in V4-V5-V6 and signs of prolonged QTc; troponin I uptake was positive. Due to presumed myocardial injury and high suspicion of coronary disease, coronary angiography was requested, which showed epicardial coronary arteries, without angiographically significant stenosis, thus confirming the presence of KS secondary to the ingestion of a laxative.

Clinical Efficacy of Treatment of Endodontic-Periodontal Lesions: A Systematic Scoping Review of Experimental Studies

BACKGROUND

In this review, we evaluated the clinical efficacy of interventions used for the treatment of endo-perio lesions (EPL).

METHODS

A systematic scoping review of clinical trials was developed.

RESULTS

Seven clinical trials were studied. In at least one study group of six of the seven evaluated trials, endodontic and periodontal treatments were performed simultaneously. All trials showed improvement in probing depth in the studied groups; nevertheless, the experimental groups of five studies demonstrated a statistically significant reduction in this parameter. An increase in clinical attachment level was also reported (p < 0.05). Most trials reported an increase in the filling of the bone defect following therapy (p < 0.05). Mechanical periodontal therapy implemented simultaneously with endodontic therapy demonstrated efficacy in the treatment of concurrent EPL without communication. Endodontic treatment and immediate periodontal surgery did not affect the result of the management of combined EPL with apical communication. The use of diode laser, the management of platelet-rich fibrin (PRF) and titanium-prepared PRF, and the implementation of bone grafts plus endodontic treatment with mineral-trioxide or gutta-percha seems to be an adequate strategy in patients with EPL.

CONCLUSIONS

The treatment of EPL using simultaneous endodontic and periodontal therapies seems to be an acceptable treatment alternative.

Clinical and Microbiological Efficacy of Adjunctive Systemic Quinolones to Mechanical Therapy in Periodontitis: A Systematic Review of the Literature

OBJECTIVES

To assess the clinical and microbiological efficacy of systemic quinolones adjunctive to mechanical therapy in periodontitis patients. Materials and Methods. A systematic review of the scientific literature was carried out. The search scheme comprised the Scopus, PubMed/MEDLINE, SCIELO (Scientific Electronic Library Online), and LILACS (Literatura Latinoamericana y del Caribe en Ciencias de la Salud) databases, together with the gray literature. MeSH terms and keywords were utilized to explore publications in all idioms. Only randomized clinical trials (RCTs) that met the selection criteria were included.

RESULTS

A total of 4 RCTs were selected. These RCTs found superior clinical and microbiological efficacy of adjunctive systemic moxifloxacin (MOX) and levofloxacin (LV) compared to subgingival debridement plus placebo. Improvements in PD and CAL were 2.4 ± 0.8 mm and 2.7 ± 0.9 mm for LV, and 1.5 ± 0.5 mm and 1.8 ± 0.5 mm for MOX, respectively. After six months of follow-up, adjunctive MOX reduced the presence of Aggregatibacter actinomycetemcomitans to imperceptible levels, while LV markedly reduced this microorganism. Some adverse events were reported in the LV group and none in the MOX group.

CONCLUSIONS

Adjunctive MOX and LV improve probing depth and clinical attachment level compared with subgingival debridement alone in patients with periodontitis. The efficacy of these quinolones against A. actinomycetemcomitans was also superior.

Association between the presence of Treponema denticola and reduced levels of antiatherogenic high density lipoprotein in periodontitis

OBJECTIVE

Dyslipidemia, a disorder in the levels of cholesterol or lipoproteins in the plasma, is a feature of atherosclerosis, leading to cardiovascular disease. The objective of this study was to evaluate whether Tanerella forsythia and Treponema denticola are related to reduced levels of antiatherogenic high density lipoprotein (HDL).

METHOD AND MATERIALS

In this cross-sectional study, 108 patients were invited to participate. The diagnosis of chronic periodontitis and the diagnosis of adipose tissue disorders were made based on criteria previously defined. The presence of T forsythia and T denticola was detected by polymerase chain reaction.

RESULTS

A total of 61 women and 19 men with chronic periodontitis, and 18 women and 10 men without periodontitis were studied. The serum levels of total cholesterol and low density lipoprotein were similar in both groups. Inversely, the levels of triglycerides (TG) were higher in periodontitis patients compared to subjects without periodontitis (178 mg/dL vs 165 mg/dL; P < .05), and the levels of HDL were lower (44 mg/dL vs 50 mg/dL; P < .05), respectively. The presence of T denticola was associated with low levels of HDL in periodontitis patients after adjustment for possible confounders (OR, 3.03; 95% CI, 1.2-7.2).

CONCLUSION

Higher levels of TG and lower levels of HDL were associated with the presence of T denticola in chronic periodontitis. These results may suggest that the presence of T denticola could reduce the antiatherogenic potency of HDL and may increase the risk for cardiovascular disease in patients with chronic periodontitis.

Mandibular Body Reconstruction Utilizing a Three-Dimensional Custom-Made Porous Titanium Plate: A Four-Year Follow-Up Clinical Report

A clinical case of a 42-year-old woman patient, who had a mandibular reconstruction utilizing a three-dimensional (3D) custom-made porous titanium plate dental restoration, is presented. She showed a recurrence of a unicystic ameloblastoma involving the left hemimandible. The patient declined to be managed by a bone-free flap. A mandibular resection in the healthy areas was provided, followed by reconstruction utilizing a 3D custom-made porous titanium plate dental restoration with a hybrid dental prosthesis. The 3D rehabilitation was created considering slim tomodensitometric sections. The cutting guides and custom-created 3D plate were fabricated employing medical software via computer-aided design and fabricating with locations planned for healing abutments. The patient was contented with the rehabilitation, and the condition continued stable at the four-year follow-up.

Gram-negative enteric rods/Pseudomonas colonization in mucositis and peri-implantitis of implants restored with cemented and screwed reconstructions: A cross-sectional study

PURPOSE

To evaluate the association between Gram-negative enteric rods and Pseudomonas with mucositis and peri-implantitis, in implants restored with cemented and screw-retained reconstructions.

MATERIALS AND METHODS

Individuals treated with implants, diagnosed with peri-implant mucositis and or peri-implantitis, participated in this study. Microbiota from the implant and the gingival sulcus of two neighboring teeth were also studied. The microorganisms were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

A total of 52 and 51 implants cemented and screwed restored were evaluated in 31 patients. The presence of Gram-negative enteric rods/Pseudomonas (P = .01) was significantly higher in the cemented restored implants. When the unit of analysis was the implant, the presence of Gram-negative enteric rods/Pseudomonas was associated with cemented restored implants after adjustment for possible confounders (odds ratio [OR] = 3.7; 95% CI, 1.4-10; P = .01); besides, peri-implantitis was statistically significant in the multivariate model (P = .008). Considering the patient as a unit of analysis, peri-implantitis was associated with cemented restored implants (OR = 9.4; 95% CI, 2-46; P = .006); this statistically significant association remained after adjusting for potential confounders (OR = 6.8; 95% CI, 1.3-37; P = .02).

CONCLUSION

The presence of Gram-negative enteric rods/Pseudomonas was associated with cemented restored implants; besides, peri-implantitis was associated with cemented restored implants.

Effects on clinical outcomes of adjunctive moxifloxacin versus amoxicillin plus metronidazole in periodontitis patients harboring Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia: exploratory analyses from a clinical trial

Objective: Considering the etiopathogenesis of periodontitis, it is relevant to evaluate the efficacy of the adjunctive use of systemic antimicrobials based on microbial occurrence. This report explores whether patients harboring Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), or Tannerella forsythia (Tf) at baseline could receive greater clinical benefits from adjunctive moxifloxacin (MXF) and amoxicillin plus metronidazole (AM+MT) in comparison to patients without the presence of these microorganisms before therapy for generalized periodontitis. A control group was established that received subgingival debridement (SD) alone.
Method and materials: Thirty-six patients younger than 30 years of age were randomly allocated to one of three treatment groups: SD plus placebo, systemic MXF with SD, or AM+MT combined with SD. Subgingival samples were studied. The effects of the therapies on probing depth and clinical attachment level, including interactions with Aa, Pg, or Tf at baseline, were explored using regression models.
Results: At 6 months, all treatment groups showed improved clinical outcomes in patients harboring Aa, Pg, or Tf at baseline compared to the patients who did not harbor these microorganisms at baseline. Indeed, in the presence of Aa, Pg, or Tf at baseline, the patients receiving antimicrobial protocols showed the most significant gains compared to the control group. Furthermore, the percentage of sites ≥ 6 mm was reduced in the test groups, compared to the control group; these periodontopathogens were not present in sites with probing depth ≥ 6 mm in the MXF group. The interactions of Aa, Pg, and Tf with the test groups significantly improved clinical parameters at 6 months (P < .001). Interestingly, the R2 value in the models that explored clinical attachment gain produced a high degree of correlation (> 0.75), indicating that a high percentage (> 75%) of the total variation in clinical attachment level gain can be explained by the independent variables.
Conclusions: Although all patients benefited from the treatments, patients harboring Aa, Pg, or Tf at baseline showed improved clinical benefits at 6 months, suggesting that Aa, Pg, or Tf at baseline may change the effects of systemic MXF and AM+MT in generalized periodontitis. After 6 months, Aa, Pg, and Tf were not present in sites with probing depth ≥ 6 mm in the MXF group.

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Comparison of frictional resistance between passive self-ligating brackets and slide-type low-friction ligature brackets during the alignment and leveling stage

BACKGROUND

To compare the frictional resistance between passive self-ligating brackets and conventional brackets with low-friction ligature under bracket/archwire and root/bone interface during dental alignment and leveling.

MATERIAL AND METHODS

A tridimensional model of the maxilla and teeth of a patient treated with conventional brackets, and slide ligatures was generated employing the SolidWorks modeling software. SmartClip self-ligating brackets and Logic Line conventional brackets were assembled with slide low-friction ligatures, utilizing archwires with different diameters and alloys used for the alignment and leveling stage. Friction caused during the bracket/archwire interface and stress during the bone/root interface were compared through a finite element model.

RESULTS

SmartClip and Logic Line brackets with slide elastomeric low-friction elastomeric ligature showed similar frictional stress values of 0.50 MPa and 0.64 MPa, respectively. Passive self-ligating brackets transmitted a lower load along the periodontal ligament, compared to conventional brackets with a low-friction ligature.

CONCLUSIONS

Slide low-friction elastomeric ligatures showed frictional forces during the bracket/archwire interface similar to those of the SmartClip brackets, while the distribution of stresses and deformations during the root/bone interface were lower in the passive self-ligating brackets. Key words:Orthodontic friction, finite element analysis, orthodontic brackets, orthodontic wires.

Portal Vein Thrombosis in Liver Transplantation: A Retrospective Cohort Study

Portal vein thrombosis was considered a contraindication for liver transplantation. This study analyzes the perioperative complications and survival of liver transplant patients with portal vein thrombosis (PVT). A retrospective observational cohort study of liver transplant patients was conducted. The outcomes were early mortality (30 days) and patient survival. A total of 201 liver transplant patients were identified and 34 (17%) patients with PVT were found. The most frequent extension of thrombosis was Yerdel 1 (58.8%), and a portosystemic shunt was identified in 23 (68%) patients. Eleven patients (33%) presented any early vascular complication, PVT being the most frequent (12%). The multivariate regression analysis showed a statistically significant association between PVT and early complications (OR = 3.3, 95% confidence interval 1.4-7.7; p = 0.006). Moreover, early mortality was observed in eight patients (24%), of which two (5.9%) presented Yerdel 2. For Yerdel 1, patient survival according to the extent of thrombosis was 75% at 1 year and 3 years, while for Yerdel 2, it was 65% at 1 year, and 50% at 3 years (p = 0.04). Portal vein thrombosis significantly influenced early vascular complications. Furthermore, portal vein thrombosis Yerdel 2 or higher impacts the survival of liver grafts in the short and long term.

Primary retromolar malignant melanoma in a Latin American patient

Primary malignant melanoma of the oral mucosa is rare and has scarcely been reported in patients from Latin America. The most frequently affected sites include the palate and gingiva of the maxilla. In this report, we describe primary malignant melanoma in a Latin American patient. A 3 × 3.5-cm black tumor was observed on the upper left retromolar area. The lesion exhibited a sessile base, irregular edges, soft consistency, and pain on palpation. Immunohistochemistry staining results were positive for S100 and HMB-45; the Ki-67 index was 20%. Contrast tomography of the skull, face, abdomen, and thorax, as well as ultrasound of the liver, did not reveal metastatic lesions. The patient underwent wide surgical excision of the lesion, followed by radiotherapy; he was subsequently rehabilitated with a somato prosthesis.

Influence of Hyrax screw position on dental movement and cortical bone: A study of finite elements

BACKGROUND

Rapid maxillary expansion (RME) has effects on the dental and periodontal structures of the parts involved, which vary according to the design and position of the expansion screw. The purpose of the study was to determine the optimal three-dimensional position of the Hyrax screw to obtain precise control of the dental movement and effect on the bone cortex using the finite element method (FEM).

MATERIAL AND METHODS

RME was performed from the patient whom two Cone-Beam computerized tomography scans (CBCT) were obtained: T1 before expansion, and T2 three months after stabilization of RME. The FEM model was designed with T1 and of Hyrax photographs. FEM was obtained by comparing the simulation, T2, and clinical results. Three sagittal screw positions (anterior-middle-posterior) and vertical (upper-medium-low) were evaluated.

RESULTS

A coronal- buccal displacement of premolars and first molars was found which decreased in the occlusal-apical direction, presenting different types of dental movement in the screw positions; besides, a tendency of translational movement in the posterior-high location was observed. In the posterior-high position a higher concentration of efforts and homogeneous deformations in the periodontal ligament and vestibular cortex of the cervical area of first molars, first and second premolars were observed, with variations according to the screw position and the distribution of stresses.

CONCLUSIONS

The ideal location of the expansion screw for controlling dental movement and periodontal side effects was the high-posterior position. Key words:Maxillary expansion, dental movement, finite element analysis, orthodontic appliances.

Antimicrobial resistance in patients with endodontic infections: A systematic scoping review of observational studies

The aim of this study was to assess the prevalence and proportions of antimicrobial-resistant species in patients with endodontic infections. A systematic scoping review of scientific evidence was accomplished involving different databases. Nine investigations were selected including 651 patients. Enterococcus faecalis was resistant to tetracycline (30%-70%), clindamycin (100%), erythromycin (10%-20%), ampicillin (9%) and azithromycin (60%). On the contrary, Prevotella spp., Fusobacterium spp., Peptostreptococcus spp. and Streptococcus spp. were resistant to penicillin, tetracycline, doxycycline, ciprofloxacin, amoxicillin, erythromycin, metronidazole and clindamycin in different proportions. Fusobacterium nucleatum showed high resistance to amoxicillin, amoxicillin plus clavulanate and erythromycin. Prevotella oralis presented a predisposition to augment its resistance to clindamycin over time. Tanerella forsythia exhibited resistance to ciprofloxacin and rifampicin. Lactococcus lactis presented robust resistance to cephalosporins, metronidazole, penicillin, amoxicillin and amoxicillin-clavulanic acid. It was observed high levels of resistance to antimicrobials that have been utilised in the local and systemic treatment of oral cavity infections.

Treatment of Class III malocclusion using Hybrid Hyrax, Face Mask and Alt-RAMEC Protocol: A Case Report in a Latin-American patient

The management of Class III malocclusion is one of the greatest challenges of orthodontics. Current treatments offer the possibility of using direct skeletal anchorage to improve clinical outcomes. This case shows the results of using a Hyrax hybrid palatal anchorage, Alt-RAMEC (Alternate Rapid Maxillary Expansion and Contraction protocol) and a facemask to treat a maxillary hypoplasia Class III malocclusion in a Latin-American patient. The appliance design and the protocol used are widely described. Clinical and cephalometric results suggest that it is a good treatment option for this Latino patient, with moderate malocclusion and limitations in the dental anchorage. Key words:ALT-RAMEC, Angle Class III, malocclusion, maxillary expansion, mini-screws, orthodontic anchorage, TADs.

Ischemic Stroke Secondary to a Stab Wound to the Neck in a Young Adult

Vertebral artery dissection is a common cause of stroke in young adults without predisposing risk factors for cerebrovascular disease. We describe the case of a 28-year-old patient who presented with an ischemic stroke secondary to a stab wound to the neck that affected the vertebral artery. A physical examination revealed neurological deterioration (Glasgow 8/15), a sutured neck wound, no palpable hematoma, no thrills, and no active bleeding. A computed tomography angiography revealed a left vertebral artery arteriovenous fistula with a component of a pseudoaneurysm, for which a neurointerventional consultation was carried out. Due to neurological compromise, the airway was secured, and because the case involved a posterior fossa infarction with compression of the fourth ventricle and obstructive secondary hydrocephalus, an external ventricular shunt was inserted by neurosurgery. A fistula occlusion was performed with five Axium coils and a vial of Squid 12; the vertebral artery was catheterized, and a craniotomy was performed to manage hydrocephalus with a 12-mm H2O collecting system. The patient was discharged on the tenth day after admission with sequelae of left hemiparesis (predominantly brachial) and no other deficits. There was no hemorrhagic transformation on the control computed tomography scans and no further complications.

Aneurysmal bone cyst of the mandible with conservative surgical management: A case report

The aneurysmal bone cyst is a nonneoplastic, osteolytic and locally destructive lesion that mainly affects the metaphyseal area of long bones and only 2% of it is diagnosed in the maxillofacial skeleton. Although surgical treatment is the most common option, it is associated to high morbidity rates. The case of an aneurysmal bone cyst of a considerable size in a 27-year-old male patient illustrating a conservative surgical approach with preservation of the dental structures in the mandible to limit aesthetic and functional side effects is presented. Two-year clinical follow-up was performed with no evidence of recurrence. Key words:Aneurysmal bone cyst; curettage, conservative treatment, mandibular osteotomy.