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OBJECTIVE: Orthognathic surgery is a viable and reproducible treatment for facial deformities. Despite the precision of the skeletal planning of surgical procedures, there is little information about the relations between hard and soft tissues in three-dimensional (3D) analysis, resulting in unpredictable soft tissue outcomes. Three-dimensional photography is a viable tool for soft tissue analysis because it is easy to use, has wide availability, low cost, and is harmless. This review aims to establish parameters for acquiring consistent and reproducible 3D facial images. METHODS: A scoping review was conducted across PubMed, SCOPUS, Scientific Electronic Library Online (SciELO), and Web of Science databases, adhering to "Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews" guidelines. Articles presenting 3D facial photographs in the diagnostic phase were considered. RESULTS: A total of 79 articles were identified, of which 29 were selected for analysis. CONCLUSION: The predominant use of automated systems like 3dMD and VECTRA M3 was noted. User positioning has highest agreement among authors. Noteworthy aspects include the importance of proper lighting, facial expression, and dental positioning, with observed discrepancies and inconsistencies among authors. Finally, the authors proposed a 3D image acquisition protocol based on this research findings.
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Cara , Imagenología Tridimensional , Fotograbar , Humanos , Imagenología Tridimensional/métodos , Cara/diagnóstico por imagen , Cara/anatomía & histología , Fotograbar/métodos , Procedimientos Quirúrgicos Ortognáticos/métodos , Reproducibilidad de los ResultadosRESUMEN
Temporomandibular Joint Replacement (TMJ-R) is used to treat maxillomandibular disease related to condylar head augmentation, condylar head reduction, absence of the condylar head and TMJ reconstruction. In most of the cases, TMJ-R could be used together with orthognathic surgery. In cases with facial asymmetry related to overgrowth of the mandibular condyle as in the cases of osteochondroma, there is a progressive facial asymmetry with enlargement of the unilateral mandibular ramus and mandibular body, creating strong mandibular contouring when comparing to the contralateral side. Usually, in this case, a lack is observed in the antegonial notch. âThe aim of this technical note âis to provide the strategy to obtain facial symmetry using the TMJ prosthesis and contouring osteotomy in the same procedure.
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Facial contouring relates to hard and soft structures that make up the face. Skeletal class II and III subjects present bone structure and position changes, significantly impacting the soft tissues. This study aims to analyze the morphology of the mandible at mandibular ramus and angle level in subjects with skeletal facial deformity class II and III who are candidates for orthognathic surgery and to define implications in facial contour. A cross-sectional study used cone beam computed tomography to compare the mandibular contour (mandibular angle and ramus region) in orthognathic surgery candidates. One hundred sixty orthognathic surgery candidates were analyzed, ranging in age from 18 to 58 years (31.29 ± 11.97). Regarding the skeletal class, 95 (59.37%) were skeletal class II, and 65 (40.62%) were skeletal class III. Class II subjects had a larger antegonial notch than class III subjects. Concerning the mandibular contour, class II subjects presented less vertical distance than class III subjects, but both presented similar gonial angles. Concerning the ideas to assess the need for mandibular contouring surgery, the 2 proposals to determine the need for mandibular contouring surgery in class II and III subjects present a similar distribution. The mandibular notch is an objective element and is commonly present in subjects with a class II facial pattern; this element can be used in contour analysis to define expected facial characteristics, including the patient's facial sex, in the decision of surgical techniques for lower facial contour augmentation or reduction.
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INTRODUCTION: Artificial intelligence (AI) is constantly developing in several medical areas and has become useful to assist with treatment planning. Orthodontics and maxillofacial surgery use AI-based technology to identify and select cephalometric points for diagnostics. Although some studies have shown promising results from the use of AI, the evidence is still limited. Hence, additional investigation is justified. MATERIALS AND METHODS: In this retrospective study, 2 human operators (1 expert and 1 inexperienced) and 1 software analyzed 30 lateral cephalograms of individuals with orthodontic treatment indications. They measured 10 cephalometric variables and then 2 weeks later, repeated measurements on 30% of the sample. We evaluated the reliability of the measurements between the 2-time points and the differences in the means between the expert operator and the AI software and between the expert and inexperienced operators. RESULTS: There was high reliability for the expert operator and AI measurements, and moderate reliability for the inexperienced operator measurements. There were some significant differences in the means produced by the AI software and the inexperienced operator compared with the expert operator. CONCLUSION: Although AI is useful for cephalometric analysis, it should be used with caution because there are differences compared with analysis by humans.
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Inteligencia Artificial , Cefalometría , Competencia Clínica , Programas Informáticos , Humanos , Cefalometría/métodos , Estudios Retrospectivos , Reproducibilidad de los Resultados , Femenino , Masculino , AdolescenteRESUMEN
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.
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Osteonecrosis de los Maxilares Asociada a Difosfonatos , Conservadores de la Densidad Ósea , Humanos , Osteonecrosis de los Maxilares Asociada a Difosfonatos/cirugía , Osteonecrosis de los Maxilares Asociada a Difosfonatos/epidemiología , Amnios , Denosumab/efectos adversos , Difosfonatos/efectos adversos , Conservadores de la Densidad Ósea/efectos adversosRESUMEN
ABSTRACT: Facial asymmetry is a challenge for surgeons. Some surgical strategies could be used involved soft or hard tissue of the face. The aim of this report is to show the use of patient specific implants (PSI) in a puzzle strategy based on computer aided design/computer aided manufacturer to solve a complex structural facial asymmetry after orthognathic surgery. Twenty-five-year-old male patient complain for facial asymmetry after orthognathic surgery; main deformity was related to the shape of mandibular bone in the ramus, angle, and body. After mirror image, was chose an augmentation in the right side using 2-pieces patient specific implants and the bone reduction in the vertical high of the mandibular body in the left side. Surgical technique was realized by intra oral approach installing the ramus segment at first approach and the body segment as second to obtain stability in the fitting implant-bone-implant; the left side was treated using a guide for osteotomy; after 1-year follow-up no infection or complication was observed and facial symmetry was obtained. It is possible to conclude that the puzzle technique using polyetheretherketone can be applied to obtain predictable results in a simple strategy to solve a complex problem.
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Implantes Dentales , Cirugía Ortognática , Procedimientos Quirúrgicos Ortognáticos , Adulto , Cefalometría , Asimetría Facial/diagnóstico por imagen , Asimetría Facial/cirugía , Huesos Faciales , Humanos , Masculino , Mandíbula , Osteotomía Sagital de Rama MandibularRESUMEN
ABSTRACT: Rates of severe complications in orthognathic surgery are low, but when they occur they can be fatal. This article reports a case of laceration of the junction of the posterior lateral nasal artery and the sphenopalatine artery, resulting in severe delayed bleeding. Patient undergoes a multiple segment Le Fort I osteotomy with no intraoperative or immediate postoperative complications. On the fourth postoperative day, he presents with epistaxis and intractable postnasal discharge, is admitted to emergency with signs of shock, and bleeding is detected endoscopically originating from the right sphenopalatine artery, which is treated with diathermocoagulation. The advantage of endoscopy in difficult areas is that bleeding complications can be solved with low morbidity.
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Arteria Maxilar , Procedimientos Quirúrgicos Ortognáticos , Arterias , Epistaxis/etiología , Humanos , Masculino , Arteria Maxilar/cirugía , Nariz , Osteotomía Le Fort/efectos adversosRESUMEN
ABSTRACT: Contour augmentation and mandibular angle modification surgery is becoming increasingly. The aim of this research is to compare technique and outcomes in augmentations done with standard implants or PEEK-based patient specific implants (PSI) in mandibular angle. Data from surgical planning, operative and post-operative of 6 months follow-up were revised for 21 patients who were submitted to facial surgery using a stock implant obtained from companies currently on the market or 3D implants created with CAD/CAM technology using PEEK 3D printing. Surgical time, intra-operative and post-operative complications were compared, analyzing the advantages and disadvantage of each technique. Statistical analyses using t-test and chi-squared were performed considering P value<â0.05 for statistical differences. Twelve patients were operated on with stock implants and nine patients with PSI. The surgical time was 15 minutes less for the 3D implant surgeries (Pâ=â0.021) and intraoperatively only the stock implants needed modifications with wear and adaptation methods; post-operative infections were observed in both groups with no significant differences (Pâ>â0.05). The 3D implants had greater levels of facial symmetry than the stock implants, although they did not present significant differences.Considering the limitations of this study, mandibular angle implants with a PEEK-based 3D CAD/CAM are efficient, stable and have a low complication rate; the CAD/CAM strategy is useful in facial surgery and can be integrated as a standard for surgical planning in facial makeover surgery.
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Mandíbula/diagnóstico por imagen , Benzofenonas , Diseño Asistido por Computadora , Humanos , Cetonas , Mandíbula/cirugía , Procedimientos Quirúrgicos Ortognáticos , Polietileno , Polietilenglicoles , Polímeros , Porosidad , Impresión Tridimensional , Prótesis e ImplantesRESUMEN
Total midface deficiency, to include the orbits, nose, zygomas, and maxilla, can occur in both syndromic and non-syndromic individuals. The treatment with combination of Le Fort III and I osteotomy could be used and it is few reported in the literature. The aim of the study is to present how technology can make the procedure for the correction of hypoplasia of the middle third more predictable and safer. The 2 clinical cases were managed under submental intubation and using VSP that generated 3D printing of oclusal splints and cutting guides. Modified oblique Le Fort III osteotomy (MOLFIIIO) and Le Fort I osteotomy were used due to patients present large sagittal discrepancy between maxilla and mandible (18 and 17âmm). The patients presented good outcomes without complications. In this study, the authors demonstrate that non-syndromic patient could be managed safety with MOLFIII and Le Fort I osteotomies for the correction of midfacial deformities using virtual surgical planning (VSP) associated with 3D printing technique and piezoelectric surgery.
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Osteotomía Le Fort , Craneotomía , Femenino , Humanos , Masculino , Mandíbula/cirugía , Maxilar/cirugía , Osteotomía Le Fort/métodos , Adulto JovenRESUMEN
OBJECTIVE: This study aimed to review the existing evidence regarding reconstruction of the alveolar cleft using recombinant human bone morphogenetic protein-2 (rhBMP-2) in terms of bone volume and bone height. DESIGN: Systematic review and meta-analysis. PATIENTSPARTICIPANTS: A systematic search was done. Randomized and nonrandomized clinical trials, where rhBMP-2 was used in the reconstruction of human alveolar cleft were included. INTERVENTIONS: Reconstruction of alveolar cleft with rhBMP-2. MAIN OUTCOME MEASURES: Average bone volume formation and average bone height formation in the alveolar cleft. Mean difference was calculated and pooled by meta-analysis. RESULTS: Of 709 identified articles, 5 studies met the inclusion criteria. The average bone volume formation was higher in the rhBMP-2 group than in the control group (61.11% vs 59.12%). The average bone height formation was higher in the control group compared to the rhBMP-2 group (75.4% vs 61.5%). The risk of bias in the selected articles was high. The meta-analysis showed that rhBMP-2 treatment may benefit bone formation compared to iliac crest graft (low certainty evidence; mean difference: -208.76; 95% confidence interval: -253.59 to -163.93; -I2 = 0%). CONCLUSIONS: The results obtained in primary articles are promising but have a high risk of bias and have low quality of evidence; therefore, it is necessary to conduct controlled clinical trials with a greater number of patients to recommend the use of rhBMP-2 in the treatment of the alveolar cleft. PROSPERO registration number: CRD42018077741.
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Proteína Morfogenética Ósea 2 , Fisura del Paladar , Fisura del Paladar/cirugía , Humanos , Proteínas Recombinantes , Factor de Crecimiento Transformador betaRESUMEN
INTRODUCTION: The purpose of this research was to prospectively determine the ratio of 2 soft-tissue landmarks, pogonion (sPg) and menton (sMe), to their hard-tissue counterparts (Pg and Me) in the sagittal and vertical directions for mandibular lengthening surgeries. METHODS: We drew a sample from the prospective Orthognathic and Orthofacial Surgery Research study, consisting of patients who underwent surgical mandibular lengthening (alone or in combination with maxillary osteotomy) without genioplasty. We digitized landmarks using Facewizz software and determined the relationships between the hard- and soft-tissue changes by correlation analysis. RESULTS: Pearson correlation test showed a significant correlation between the type of surgery and the sPg:Pg and sMe:Me ratios. The sPg:Pg ratio was 87% for mandibular lengthening only and 102% for mandibular lengthening in combination with maxillary surgery. The sMe:Me ratio was 85% and 96% for upward and downward movements, respectively. CONCLUSIONS: The average ratios presented in this study for the pogonion and menton can aid in preoperative planning by providing estimates for soft-tissue behavior. Further stratifications will be possible after the Orthognathic and Orthofacial Surgery Research database is enriched with more inclusions.
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Avance Mandibular , Procedimientos Quirúrgicos Ortognáticos , Cefalometría , Mentón/anatomía & histología , Humanos , Mandíbula , Estudios ProspectivosRESUMEN
PURPOSE: We present a series of cases of mandibular symphysis fractures treated at our institution with a 3-dimensional strut plate. The aim of the present study was to confirm the stability of this fixation technique and discuss its advantages, disadvantages, and potential complications. PATIENTS AND METHODS: We designed and implemented a retrospective cohort study of patients who underwent surgery by the same surgeon at our institution from July 2012 to April 2014 for a mandible fracture with a symphysis component. The patients were evaluated to identify aspects of occlusion, fracture mobility, postoperative infection, and the need for hardware removal. RESULTS: The sample included 12 subjects who had met the inclusion criteria. The inclusion criteria were a linear noncomminuted fracture, sufficient distance from the mental foramina, a maximum of 5 days between the trauma and surgery, and a minimum postoperative period of 3 months. The mean age of the sample was 33.4 years, and 1 of the 12 patients (8.3%) was female. Of the 12 patients, 10 did well, and 2 developed a surgical site infection, 1 of whom also experienced nonunion and required additional fixation. CONCLUSIONS: The results of the present study suggest a 3-dimensional strut plate applied to symphysis fractures provides adequate fracture stabilization with a risk of complications comparable to that of more traditional fixation methods. In addition, the technique has the added advantage of minimal manipulation and adaptation, which could shorten the overall operating time.
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Placas Óseas , Fijación Interna de Fracturas/métodos , Fracturas Mandibulares/cirugía , Adulto , Humanos , Fracturas Mandibulares/diagnóstico por imagen , Complicaciones Posoperatorias , Diseño de Prótesis , Radiografía Panorámica , Reoperación , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
The aim of this study was to analyze the presence of complications related to orthognathic surgery performed by surgeons in train. A retrospective study was conducted between 2005 and 2014, analyzing the clinical records of patients treated in the authors' Department. Patients who underwent orthognathic surgery were included, under a bidimensional analysis and with the conventional orthosurgical sequence; intraoperative complications were identified, such as the occurrence of a bad split, bleeding, tissue injury, among others and postoperative variables such as impaired sensation, infection, and alterations in the osteosynthesis systems. A statistical analysis was done using χ and Student t tests, considering a statistical significance when Pâ<â0.05. Two hundred fifty patients were included with an average follow-up of 13 months; 62.8% were women and 37.2% were men; 18.8% of the subjects presented some type of intraoperative or postoperative complication; excluding relapse and complications due to loss of bonding of the orthodontic device, a 12.4% complication rate was observed; intraoperative complications were 8% and postoperative complications 10.4%. Only the sensorineural alterations were associated with the mandibular surgery (Pâ<â0.05). Finally, orthognathic surgery is relatively safe and produces a low number of complications when it is performed by surgeons in train.
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Complicaciones Intraoperatorias/etiología , Procedimientos Quirúrgicos Ortognáticos/efectos adversos , Complicaciones Posoperatorias/etiología , Adolescente , Adulto , Pérdida de Sangre Quirúrgica , Femenino , Humanos , Infecciones/etiología , Masculino , Procedimientos Quirúrgicos Ortognáticos/educación , Estudios Retrospectivos , Trastornos de la Sensación/etiología , Adulto JovenRESUMEN
The diagnosis of unilateral condylar hyperplasia (UCH) requires a combined assessment consisting of clinical, radiological, and histopathological examination. The etiology of this condition is unknown. The purpose of this study is to report a rare case of UCH in a monozygotic twin. A 15-year-old girl was referred to our department complaining of facial asymmetry and malocclusion. Computed tomography and single-photon emission computed tomography imaging reveal enlargement of the left condyle and condylar neck, and an increased uptake that was diagnosed as active UCH. During the investigation of family and co-twin facial profile, no cases of UCH were identified. From the case reported in this study, the authors raise a hypothesis that can exist some environmental factor that is related in the development of condylar hyperplasia given the occurrence of this disease in one of twins.
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Enfermedades Óseas/diagnóstico por imagen , Enfermedades Óseas/patología , Enfermedades en Gemelos/etiología , Asimetría Facial/etiología , Maloclusión/etiología , Cóndilo Mandibular/patología , Adolescente , Enfermedades Óseas/complicaciones , Femenino , Humanos , Hiperplasia/complicaciones , Hiperplasia/diagnóstico por imagen , Hiperplasia/patología , Masculino , Tomografía Computarizada de Emisión de Fotón Único , Tomografía Computarizada por Rayos X , Gemelos MonocigóticosRESUMEN
PURPOSE: The aim was to determine the survival rate of dental implants installed in the posterior region of the maxilla after a graftless maxillary sinus lift via the lateral window approach and to identify the factors involved in the results. MATERIALS AND METHODS: A systematic search was done on MEDLINE, EMBASE, LILACS, Scopus, and Science Direct up to June 2016; additional studies were identified through an analysis of references. Primary studies in English, Spanish, Portuguese, and French were included; the selection and data extraction process was conducted by 2 investigators independently, and the methodological quality was evaluated by means of the Effective Public Health Practice Project's Quality Assessment Tool. RESULTS: The combined search identified 232 articles. After the selection process, 11 articles were identified, 9 of which were prospective and 2 were retrospective. In all of them, the graftless maxillary sinus lift was done with the immediate installation of the implant. All the studies included presented a low methodological quality. The mean survival rate of the implants was 97% with an average new intrasinus bone formation of 6.2 mm. CONCLUSION: This technique has a high implant survival although it is not possible to identify its correct indication and contraindication.
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Elevación del Piso del Seno Maxilar/métodos , Implantación Dental Endoósea/métodos , Implantes Dentales , Humanos , Seno Maxilar/cirugíaRESUMEN
OBJECTIVE: To evaluate the microscopic structure and chemical composition of titanium dental implants removed from patients with implant failure. MATERIALS AND METHODS: Thirty-eight dental implants removed from 29 patients between January 2012 and September 2014 were studied by metallographic analysis, and 7 of these implants were also studied by energy-dispersive x-ray (EDX) analysis. Medical records of these patients were examined. RESULTS: Dental implants were removed in a median of 54.6 ± 88.1 weeks after insertion. The lack of osseointegration without symptomatology or signs of infection was the main reason for implant failure (55.17%). Seventeen patients presented implant failure in the maxilla and 12 patients in the mandible. Metallographic analysis revealed that all the dental implants were manufactured from commercially pure titanium, presenting microscopic uniform appearance, with no "alpha case". The implants studied by EDX analysis presented between 99.85% and 99.87% of titanium and 0.13% and 0.15% of iron by mass. All the implants evaluated were within the ASTM specifications in both analyses. CONCLUSION: There was no relationship between dental implant failure and the microscopic structure and chemical composition of these devices.
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Fracaso de la Restauración Dental , Implantación Dental Endoósea/efectos adversos , Implantación Dental Endoósea/métodos , Implantes Dentales/efectos adversos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Espectrometría por Rayos X , Titanio/uso terapéutico , TorqueRESUMEN
PURPOSE: To compare the condylar volume of patients with unilateral condylar hyperplasia (UCH) with that of patients with a Class III skeletal relation. MATERIALS AND METHODS: Twenty cone-beam computed tomograms of patients were analyzed. Images were divided into 2 groups: 10 from patients with transverse asymmetry of the face and 10 from patients with a Class III facial deformity. Patients' ages ranged from 15 to 30 years. Volumetric data were reconstructed using Dolphin 3D software (Dolphin Imaging & Management Solutions, Chatsworth, CA). This software measured the condylar volume above the deepest point of the sigmoid notch, the lower arch midline deviation, and the overjet. RESULTS: The condyle with hyperplasia exhibited the largest volume (1.97 ± 0.52 cm3) and a statistically significant difference compared with the contralateral condyle (χ2 = 14.30; P < .01). The Class III condyle exhibited relative symmetry of volume between the left and right sides. These condyles exhibited a larger volume compared with the non-hyperplastic condyles in the UCH group, with a statistically significant difference (χ2 = 6.22; P = .013; χ2 = 5.50; P = .019). CONCLUSIONS: Hyperplastic condyles were similar in volume to the condyles of patients with mandibular prognathism, suggesting that patients with a Class III skeletal relation could exhibit bilateral condylar hyperplasia.
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Deformidades Dentofaciales/patología , Cóndilo Mandibular/patología , Adolescente , Adulto , Tomografía Computarizada de Haz Cónico , Deformidades Dentofaciales/complicaciones , Deformidades Dentofaciales/diagnóstico por imagen , Femenino , Humanos , Hiperplasia , Masculino , Maloclusión de Angle Clase III/complicaciones , Maloclusión de Angle Clase III/diagnóstico por imagen , Maloclusión de Angle Clase III/patología , Cóndilo Mandibular/anomalías , Cóndilo Mandibular/diagnóstico por imagen , Tamaño de los Órganos , Adulto JovenRESUMEN
PURPOSE: The aim of the present study was to determine the success rate of autotransplanted permanent teeth with an open apex and to identify the most influential prognostic factors. MATERIALS AND METHODS: A systematic search of the MEDLINE, EMBASE, LILACS, and SciELO databases was conducted for January 1990 to August 2015. The study eligibility criteria were primary studies that had evaluated patients with autotransplantation with an open apex, with or without preparation of the socket, and a minimum of 12 months of follow-up. The principal outcome was the success rate of autotransplanted teeth with an open apex. Two of us independently performed the selection process and data extraction. The Effective Public Health Practice Project's Quality Assessment Tool was used for the quality assessment of the studies. The odds ratio (OR) was calculated, with the 95% confidence interval (CI). RESULTS: A total of 21 studies were included in the present analysis. Of the 21 studies, 10 were retrospective and 11 were prospective. All the studies were of weak methodologic quality. The overall success rate was 89.68%, the survival rate was 98.21%, and the mean follow-up period was 6 years, 3 months (standard deviation 5.81 years). Among the prognostic factors analyzed, the premolars had a lower failure risk than did the molars (OR, 0.46; 95% CI, 0.25 to 0.84). The stage of development of the root and the autotransplantation receptor site showed no statistically significant differences. CONCLUSIONS: The overall success rate and survival were high, despite the methodologic limitations of the included studies. Further study is needed of the prognostic factors that influence the success of autotransplantation with an open apex.
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Diente/trasplante , Humanos , Ápice del Diente/trasplante , Trasplante Autólogo , Resultado del TratamientoRESUMEN
OBJECTIVE: Auricular prostheses are artificial substitutes for facial defects. The retention of these has often been a problem. This study aimed to evaluate the mechanical behavior of 3 retained auricular prosthetic connections when submitted to a mechanical cycling test. MATERIALS AND METHODS: Twelve samples with installed implants were obtained and divided into 3 groups according to their retention system with 4 samples in each group. I: bar-clip system; II: magnet system; and III: ball/o-ring system. Each of samples was submitted to the pull-out test during 3240 cycles (fâ=â0.5âHz) to determine its tensile strength. The mechanical cycling test was performed using the servo-hydraulic machine MTS 810-Flex Test 40 (Eden Prairie, MN) that had a 2.5âmm shift at a 10âmm/s velocity. The retaining strength for each of the samples was obtained at 7 intervals. RESULTS: The tensile strength for the group retained by the bar-clip system (29.60âN) was higher with statistically significant difference (Pâ<â0.05) when compared with the group retained by the ball/o-ring system (9.41âN) and magnets system (8.61 N) for all periods assessed. The ball/o-ring system showed loss of retention during the fatigue test (Kruskal-Wallis, chi-squaredâ=â17.28; Pâ<â0.01). CONCLUSIONS: The evaluated systems showed a tensile strength compatible with the clinical use and no fractures of the components were observed.
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Interfase Hueso-Implante , Oído Externo/cirugía , Prótesis e Implantes , Diseño de Prótesis , Retención de la Prótesis/métodos , Fenómenos Biomecánicos , Humanos , Falla de Prótesis , Resistencia a la TracciónRESUMEN
PURPOSE: To evaluate in vitro resistance of 5 techniques of internal fixation of bilateral fractures involving the mandibular angle and body. MATERIALS AND METHODS: Twenty-five polyurethane mandibles were used as substrates, fixed with a 2-mm fixation system, and divided into 5 groups: I, 1 4-hole plate, without intermediate space, in the neutral zone of the mandibular body and another similar plate in the external oblique ridge of the contralateral mandibular angle; II, 1 6-hole plate, with intermediate space, in the neutral zone of the mandibular body and a similar plate in the external oblique ridge of the left mandibular angle; III, 1 4-hole locking plate, with intermediate space, in the right neutral zone and another similar plate in the left external oblique ridge; IV, 2 4-hole plates, with intermediate space, one in the tension zone and the other in the compression zone of the mandibular body, and 1 4-hole plate, with intermediate space, in the external oblique ridge of the contralateral mandibular angle; V, 2 4-hole plates with intermediate space, one in the tension zone and the other in the compression zone of the mandibular body and similarly in the buccal side of the left mandibular angle. Mandibles were subjected to vertical linear load tests by a mechanical testing machine (Instron 4411, Instron Corp, Norwood, MA) to record peak load and load for displacements of 3, 5, and 7 mm. RESULTS: Group I had the least mechanical resistance of all groups, regardless of displacement, and group IV had the greatest mechanical resistance. Among groups II, III, and V, there was no statistically meaningful difference. CONCLUSION: Fixation of bilateral mandibular fractures involving the mandibular angle and body using 2 plates in the region of the body and 1 plate in the tension zone in the region of the mandibular angle was the technique that presented the best mechanical resistance.