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OBJECTIVE: This study aimed to compare the efficacy of acellular xenogeneic dermal matrix graft (AXDM) compared to connective tissue graft (CTG) in treating multiple gingival recessions. MATERIALS AND METHODS: A systematic search of electronic databases was conducted to identify randomized clinical trials (RCTs) that compared AXDM and CTG. The selected studies were subjected to bias risk assessment, data extraction, and meta-analyses. Parameters such as gingival recession height, width, mean percentage of root coverage, and complete root coverage were analyzed. RESULTS: Seven RCTs involving 146 patients were included. The meta-analyses indicated that CTG was statistically superior to AXDM in reducing gingival recession height at the final follow-up (mean difference: -0.104 mm, 95% confidence interval [CI]: -0.180-0.028, p = 0.008) and width at the final follow-up (mean difference: -0.285 mm, 95% CI: -0.541-0.030, p = 0.029). CTG also demonstrated a significantly higher mean percentage of root coverage at the 6-month follow-up (difference in means: -2.761 mm, 95% CI: -4.932-0.590, p = 0.013) and a higher percentage of complete root coverage at the 6-month follow-up (odds Ratio [OR]: 0.598, 95% CI: 0.4-0.892, p = 0.012) compared to AXDM. However, there was no significant difference in the number of teeth with complete root coverage between CTG and AXDM (OR: 1.610, 95% CI: 0.983-2.636, p = 0.058) and aesthetic outcomes (mean difference: 0.148, 95% CI: -0.277-0.573, p = 0.494). CONCLUSIONS: CTG is more effective than AXDM in treating multiple gingival recessions. This is evidenced by significant reductions in gingival recession height and width, a higher mean percentage of root coverage, and a greater percentage of complete root coverage at the 6-month follow-up. CLINICAL RELEVANCE: In some clinical situations an alternative to CTG is required for the treatment of multiple gingival recessions. AXDM, despite presenting clinical outcomes that are not as satisfactory as CTG, can be used for this purpose.
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Dermis Acelular , Recesión Gingival , Recesión Gingival/cirugía , Humanos , Tejido Conectivo/trasplanteRESUMEN
The objective of this systematic review was to identify the available scientific evidence on bone substitutes (BSs) compared with autogenous bone grafts (ABGs) for regeneration of horizontal bone resorption in the anterior maxillary alveolar process, aiming at rehabilitation with endosseous implants. This review was performed according to the PRISMA guidelines (2020) and registered in the database PROSPERO (CRD: 42017070574). The databases searched were PUBMED/MEDLINE, EMBASE, SCOPUS, SCIENCE DIRECT, WEB OF SCIENCE, and CENTRAL COCHRANE, in the English language. The Australian National Health and Medical Research Council (NHMRC) and Cochrane Risk of Bias Tool were used to assess the study's quality and risk of bias. A total of 524 papers were found. After the selection process, 6 studies were selected for review. A total of 182 patients were followed for a period of 6 to 48 months. The mean age of patients was 46.46 years, and 152 implants were installed in the anterior region. Two studies achieved a reduced graft and implant failure rate, whereas the remaining 4 studies had no losses. It may be concluded that the use of ABGs and some BSs is a viable alternative for the rehabilitation with implants in individuals with anterior horizontal bone loss. However, additional randomized controlled trials are warranted due to the limited number of papers.
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Aumento de la Cresta Alveolar , Sustitutos de Huesos , Implantes Dentales , Humanos , Persona de Mediana Edad , Sustitutos de Huesos/uso terapéutico , Australia , Implantación Dental Endoósea , Trasplante ÓseoRESUMEN
The objective of this study was to perform a quality analysis of systematic reviews with meta-analyses that focused on the comparison of platform-switching (implant-abutment mismatching) and platform-matched (PM) implants. The assessment of multiple systematic reviews (AMSTAR) and Glenny (Checklist) Scales were used to qualify the studies. PubMed, Scientific Electronic Library Online (SciELO), Web of Science (formerly ISI Web of Knowledge), and Cochrane databases were searched, by topic, for systematic reviews on dental implants with switching platforms. A total of 8 systematic reviews, including 7 studies with meta-analyses, were selected. The AMSTAR scale indicated a high (n = 6) to moderate (n = 2) score for the included studies. The quantitative analysis indicated that platform-switching implants preserved more bone tissue when compared with platform-matched implants (6 meta-analyses; P < .001, smaller mean difference: -0.29 mm, 95% CI: -0.38, -0.19 and greater mean difference: -0.49 mm, 95% CI: -0.73, -0.26). Quantitative analysis based on 7 systematic reviews with meta-analysis indicated positive peri-implant bone preservation for implants restored with an implant-abutment mismatching (PSW). Further, there is evidence to improve the design of current systematic reviews. Future systematic reviews in this thematic area should consider searches in gray literature and different databases and include only randomized controlled clinical studies.
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Diseño de Implante Dental-Pilar , Implantes Dentales , Metaanálisis como Asunto , Revisiones Sistemáticas como Asunto , Huesos , Control de CalidadRESUMEN
The purpose of this study was to evaluate different retention systems (cement- or screw-retained) and crown designs (non-splinted or splinted) of fixed implant-supported restorations, in terms of stress distributions in implants/components and bone tissue, by 3-dimensional (3D) finite element analysis. Four 3D models were simulated with the InVesalius, Rhinoceros 3D, and SolidWorks programs. Models were made of type III bone from the posterior maxillary area. Models included three 4.0-mm-diameter Morse taper (MT) implants with different lengths, which supported metal-ceramic crowns. Models were processed by the Femap and NeiNastran programs, using an axial force of 400 N and oblique force of 200 N. Results were visualized as the von Mises stress and maximum principal stress (σmax). Under axial loading, there was no difference in the distribution of stress in implants/components between retention systems and splinted crowns; however, in oblique loading, cemented prostheses showed better stress distribution than screwed prostheses, whereas splinted crowns tended to reduce stress in the implant of the first molar. In the bone tissue cemented prostheses showed better stress distribution in bone tissue than screwed prostheses under axial and oblique loading. The splinted design only had an effect in the screwed prosthesis, with no influence in the cemented prosthesis. Cemented prostheses on MT implants showed more favorable stress distributions in implants/components and bone tissue. Splinting was favorable for stress distribution only for screwed prostheses under oblique loading.
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Implantes Dentales , Diseño de Prótesis Dental , Análisis de Elementos Finitos , Maxilar/cirugía , Pilares Dentales , Análisis del Estrés Dental , HumanosRESUMEN
The aim of this study was to evaluate the effect of varying the diameter, connection type and loading on stress distribution in the cortical bone for implants with a high crown-implant ratio. Six 3D models were simulated with the InVesalius, Rhinoceros 3D 4.0 and SolidWorks 2011 software programs. Models were composed of bone from the posterior mandibular region; they included an implant of 8.5 mm length, diameter Ø 3.75 mm or Ø 5.00 mm and connection types such as external hexagon (EH), internal hexagon (IH) and Morse taper (MT). Models were processed using the Femap 11.2 and NeiNastran 11.0 programs and by using an axial force of 200 N and oblique force of 100 N. Results were recorded in terms of the maximum principal stress. Oblique loading showed high stress in the cortical bone compared to that shown by axial loading. The results showed that implants with a wide diameter showed more favorable stress distribution in the cortical bone region than regular diameter, regardless of the connection type. Morse taper implants showed better stress distribution compared to other connection types, especially in the oblique loading. Thus, oblique loading showed higher stress concentration in cortical bone tissue when compared with axial loading. Wide diameter implant was favorable for improved stress distribution in the cortical bone region, while Morse taper implants showed lower stress concentration than other connections.
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Coronas , Implantes Dentales , Análisis de Elementos Finitos , Humanos , Estrés MecánicoRESUMEN
A biomechanical analysis of different types of implant connections is relevant to clinical practice because it may impact the longevity of the rehabilitation treatment. Therefore, the objective of this study is to evaluate the Morse taper connections and the stress distribution of structures associated with the platform switching (PSW) concept. It will do this by obtaining data on the biomechanical behavior of the main structure in relation to the dental implant using the 3-dimensional finite element methodology. Four models were simulated (with each containing a single prosthesis over the implant) in the molar region, with the following specifications: M1 and M2 is an external hexagonal implant on a regular platform; M3 is an external hexagonal implant using PSW concept; and M4 is a Morse taper implant. The modeling process involved the use of images from InVesalius CT (computed tomography) processing software, which were refined using Rhinoceros 4.0 and SolidWorks 2011 CAD software. The models were then exported into the finite element program (FEMAP 11.0) to configure the meshes. The models were processed using NeiNastram software. The main results are that M1 (regular diameter 4mm) had the highest stress concentration area and highest microstrain concentration for bone tissue, dental implants, and the retaining screw (P<0.05). Using the PSW concept increases the area of the stress concentrations in the retaining screw (P<0.05) more than in the regular platform implant. It was concluded that the increase in diameter is beneficial for stress distribution and that the PSW concept had higher stress concentrations in the retaining screw and the crown compared to the regular platform implant.
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Implantes Dentales , Diseño de Prótesis Dental/métodos , Programas Informáticos , HumanosRESUMEN
STATEMENT OF PROBLEM: Radiotherapy has been considered a contraindication for rehabilitation with dental implants because it can change the survival rate of implants. Nevertheless, the installation of implants in irradiated patients has been used with varying success. PURPOSE: The purpose of this systematic review was to compare the success rate of implants placed in irradiated human bone tissue with that of implants placed in nonirradiated areas. MATERIAL AND METHODS: Searches were performed in the EMBASE, Cochrane, and PubMed/Medline databases up to December 2013 to identify clinical trials addressing the subject. This systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The relative risks of implant failure and survival curves were calculated considering a confidence interval of 95%. Heterogeneity was analyzed by using a funnel chart. RESULTS: A total of 40 studies involving 2220 participants and 9231 dental implants were selected. The survival curve of the studies indicated a survival rate of 84.3% for implants installed in irradiated bone tissue. The meta-analysis indicated statistically significant differences (P<.001) between item success rates of implants placed in irradiated areas and those of implants placed in nonirradiated areas. CONCLUSIONS: Dental implants installed in the irradiated area of an oral cavity have a high survival rate, but strict monitoring is needed to prevent complications, thereby reducing possible failures.
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Implantes Dentales , Fracaso de la Restauración Dental , Neoplasias de Cabeza y Cuello/radioterapia , Análisis de Falla de Equipo , Humanos , Maxilares/efectos de la radiación , Estimación de Kaplan-MeierRESUMEN
PURPOSE: To evaluate a modified experimental model for medication-related osteonecrosis of the jaw (MRONJ) through the upper right central incisor extraction followed by intravenous bisphosphonate administration. METHODS: Forty five rats underwent the upper right central incisor tooth extraction were divided in 2 groups: Group I - experimental group, 30 rats received an intravenous administration protocol of zoledronic acid 35µg/kg into the tail vein every two weeks, totalizing four administrations, during eight weeks of administration, previously the extraction, and Group II - control group, 15 rats didn't received any medication before extraction. The groups were subdivided in postoperative periods: 14/28/42 days. Clinical analysis and microtomography were performed to verify the presence of osteonecrosis. In addition, descritive histological analysis of hematoxylin-eosin stained sections was performed to evaluate the presence of osteonecrosis or necrotic foci. RESULTS: Twelve (40%) rats, from experimental group, showed clinical signs of MRONJ (p=0.005), however, all samples showed imaginologic findings like osteolysis and loss of integrity of the cellular walls (p≤0.001). Microscopic evaluation revealed osteonecrosis areas with microbial colonies and inflammatory infiltrate (p≤0.001). In the control group, all animals presented the chronology of a normal wound healing. CONCLUSIONS: The presence of medication-related osteonecrosis of the jaw after maxillary central incisor extraction in rats. This new experimental model may be considered an option for the study of MRONJ.
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Osteonecrosis de los Maxilares Asociada a Difosfonatos/patología , Difosfonatos/administración & dosificación , Imidazoles/administración & dosificación , Modelos Animales , Administración Intravenosa/métodos , Pérdida de Hueso Alveolar/diagnóstico por imagen , Animales , Osteonecrosis de los Maxilares Asociada a Difosfonatos/diagnóstico por imagen , Difosfonatos/efectos adversos , Imidazoles/efectos adversos , Incisivo/cirugía , Masculino , Enfermedades Maxilares/diagnóstico por imagen , Osteítis/patología , Osteólisis/inducido químicamente , Osteólisis/diagnóstico por imagen , Ratas Wistar , Extracción Dental/efectos adversos , Extracción Dental/métodos , Microtomografía por Rayos X/instrumentación , Ácido ZoledrónicoRESUMEN
BACKGROUND: The purpose of this study is to analyze the tension distribution on bone tissue around implants with different angulations (0°, 17°, and 30°) and connections (external hexagon and tapered) through the use of three-dimensional finite element and statistical analyses. METHODS: Twelve different configurations of three-dimensional finite element models, including three inclinations of the implants (0°, 17°, and 30°), two connections (an external hexagon and a tapered), and two load applications (axial and oblique), were simulated. The maximum principal stress values for cortical bone were measured at the mesial, distal, buccal, and lingual regions around the implant for each analyzed situation, totaling 48 groups. Loads of 200 and 100 N were applied at the occlusal surface in the axial and oblique directions, respectively. Maximum principal stress values were measured at the bone crest and statistically analyzed using analysis of variance. Stress patterns in the bone tissue around the implant were analyzed qualitatively. RESULTS: The results demonstrated that under the oblique loading process, the external hexagon connection showed significantly higher stress concentrations in the bone tissue (P <0.05) compared with the tapered connection. Moreover, the buccal and mesial regions of the cortical bone concentrated significantly higher stress (P <0.005) to the external hexagon implant type. Under the oblique loading direction, the increased external hexagon implant angulation induced a significantly higher stress concentration (P = 0.045). CONCLUSIONS: The study results show that: 1) the oblique load was more damaging to bone tissue, mainly when associated with external hexagon implants; and 2) there was a higher stress concentration on the buccal region in comparison to all other regions under oblique load.
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Diseño de Implante Dental-Pilar , Implantación Dental Endoósea/métodos , Implantes Dentales , Análisis de Elementos Finitos , Imagenología Tridimensional/métodos , Silicatos de Aluminio/química , Proceso Alveolar/fisiología , Fuerza de la Mordida , Aleaciones de Cromo/química , Simulación por Computador , Materiales Dentales/química , Porcelana Dental/química , Módulo de Elasticidad , Humanos , Modelos Biológicos , Distribución de Poisson , Compuestos de Potasio/química , Estrés Mecánico , Titanio/química , Cemento de Fosfato de Zinc/químicaRESUMEN
The purpose of this study was to assess the influence of the crown height of external hexagon implants on the displacement and distribution of stress to the implant/bone system, using the three-dimensional finite element method. The InVesalius and Rhinoceros 4.0 softwares were used to generate the bone model by computed tomography. Each model was composed of a bone block with one implant (3.75 x 10.0 mm) with external hexagon connections and crowns with 10 mm, 12.5 mm and 15 mm in height. A 200 N axial and a 100 N oblique (45°) load were applied. The models were solved by the NeiNastran 9.0 and Femap 10.0 softwares to obtain the results that were visualized by maps of displacement, von Mises stress (crown/implant) and maximum principal stress (bone). The crown height under axial load did not influence the stress displacement and concentration, while the oblique loading increased these factors. The highest stress was observed in the neck of the implant screw on the side opposite to the loading. This stress was also transferred to the crown/platform/bone interface. The results of this study suggest that the increase in crown height enhanced stress concentration at the implant/bone tissue and increased displacement in the bone tissue, mainly under oblique loading.
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Coronas , Implantes Dentales , Retención de Prótesis Dentales/instrumentación , Prótesis Dental de Soporte Implantado , Análisis del Estrés Dental/métodos , Modelos Dentales , Fenómenos Biomecánicos , Aleaciones Dentales , Diseño de Prótesis Dental , Análisis de Elementos Finitos , Programas Informáticos , Tomografía Computarizada por Rayos XRESUMEN
PURPOSE: The aim of this study was to evaluate the bone repair process in the maxillary sinus in monkeys treated with high-density porous polyethylene (Medpor) METHODS: Four capuchin monkeys (Cebus apella) were submitted to bilateral horizontal osteotomies in the anterior wall of the maxillary sinus and divided into 2 groups: control group, left side with no implants, and porous polyethylene group, right side with Medpor. After a period of 145 days after implant placement, the maxillae were removed for histologic and histometric analyses. RESULTS: Bone repair in osteotomized areas took place by connective tissue in 58.5% and 58.7% in the control group and the porous polyethylene group, respectively. In the contact surface with Medpor, bone repair occurred in 41.3%. CONCLUSIONS: Medpor was not reabsorbed within the period of this study and allowed bone repair surrounding it. The porous polyethylene constitutes a feasible alternative for bone defect reconstruction.
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Implantes Dentales , Seno Maxilar/cirugía , Animales , Materiales Biocompatibles , Cebus , Implantación Dental Endoósea , Oseointegración , Osteotomía , Polietilenos , PorosidadRESUMEN
The prosthetic treatments play a role in the rehabilitation of patients with congenital and acquired cleft palate. To prepare the surgical field and/or correct inevitable sequelae of the surgery, the rehabilitation with obturator prosthesis is an auxiliary or complementary treatment to surgical treatments. In cases where the surgical treatment is contraindicated, the prosthetic rehabilitation becomes a definitive treatment. The denture is planned and fabricated according to each patient. Therefore, the aim of this study was to discuss the prosthetic rehabilitation performed in patients with oronasal communication.
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Enfermedades Nasales/rehabilitación , Fístula Oral/rehabilitación , Obturadores Palatinos , Fístula del Sistema Respiratorio/rehabilitación , Materiales Dentales/clasificación , Diseño de Prótesis Dental , Prótesis Dental de Soporte Implantado , Diseño de Dentadura , Humanos , Arcada Edéntula/rehabilitación , Arcada Parcialmente Edéntula/rehabilitación , Obturadores Palatinos/clasificaciónRESUMEN
The use of craniofacial implants is an effective treatment for patients with deformities, burns, and cancer sequelae. The sites with the most successful implants are the auricular, nasal, and orbital regions. Furthermore, other factors can affect the implant longevity such as irradiated area, surgical technique, bone quality and quantity, macrostructure and microstructure of the implant, maintenance, and systemic factors.
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Anomalías Craneofaciales/cirugía , Procedimientos Quirúrgicos Orales , Prótesis e Implantes , Humanos , OseointegraciónRESUMEN
The aim of this study was to evaluate the stress distribution of platform switching implants using a photoelastic method. Three models were constructed of the photoelastic resin PL-2, with a single implant and a screw-retained implant-supported prosthesis. These models were Model A, platform 5.0 mm/abutment 4.1 mm; Model B, platform 4.1 mm/abutment 4.1 mm; and Model C, platform 5.00 mm/abutment 5.00 mm. Axial and oblique (45°) loads of 100 N were applied using a Universal Testing Machine (EMIC DL 3000). Images were photographed with a digital camera and visualized with software (AdobePhotoshop) to facilitate the qualitative analysis. The highest stress concentrations were observed at the apical third of the 3 models. With the oblique load, the highest stress concentrations were located at the implant apex, opposite the load application. Stress concentrations decreased in the cervical region of Model A (platform switching), and Models A (platform switching) and C (conventional/wide-diameter) displayed similar stress magnitudes. Finally, Model B (conventional/regular diameter) displayed the highest stress concentrations of the models tested.
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Pilares Dentales , Implantes Dentales de Diente Único , Diseño de Prótesis Dental , Prótesis Dental de Soporte Implantado , Fenómenos Biomecánicos , Fuerza de la Mordida , Aleaciones de Cromo/química , Gráficos por Computador , Análisis del Estrés Dental/instrumentación , Humanos , Procesamiento de Imagen Asistido por Computador , Ensayo de Materiales , Modelos Anatómicos , Fotograbar , Resinas Sintéticas/química , Estrés Mecánico , Propiedades de SuperficieRESUMEN
Fluoride has been widely used in dentistry as a caries prophylactic agent. However, there has been some speculation that excess fluoride could cause an impact on genome integrity. In the current study, the potential DNA damage associated with exposure to fluoride was assessed in cells of blood, liver, kidney, thyroid gland and urinary bladder by the single cell gel (comet) assay. Male Wistar rats aging 75 days were distributed into seven groups: Groups 1 (control), 2, 3, 4, 5, 6 and 7 received 0 (deionized water), 10, 20, 40, 60, 80 and 100 mgF/Kg body weight from sodium fluoride (NaF), respectively, by gastrogavage. These groups were killed at 2 h after the administration of the fluoride doses. The level of DNA strand breaks did not increase in all organs evaluated and at all doses of NaF tested, as depicted by the mean tail moment. Taken together, our results suggest that oral exposure to NaF did not result in systemic genotoxic effect in multiple organs related to fluoride toxicity. Since DNA damage is an important step in events leading to carcinogenesis, this study represents a relevant contribution to the correct evaluation of the potential health risk associated with chemical exposure.