Effects of Low-Level Laser Therapy and Purified Natural Latex (Hevea brasiliensis) Protein on Injured Sciatic Nerve in Rodents: Morpho-Functional Analysis.

The present study analyzed the effects of low-level laser therapy (LLLT) and the purified natural latex protein (Hevea brasiliensis, F1 protein) on the morpho-function of sciatic nerve crush injuries in rats. One-hundred and eight male Wistar rats were randomly allocated to six groups (n = 18): 1. Control; 2. Exposed (nerve exposed); 3. Injury (injured nerve without treatment); 4. LLLT (injured nerve irradiated with LLLT (15 J/cm2, 780 nm)); 5. F1 (injured nerve treated with F1 protein (0.1%)); and 6. LLLT + F1 (injured nerve treated with LLLT and F1). On the 1st, 7th, 14th, and 56th days after injury, a functional sensory analysis of mechanical allodynia and mechanical hyperalgesia and a motor analysis of grip strength and gait were performed. After 3, 15, and 57 days, the animals were euthanized for morphometric/ultrastructural analyses. The treatments applied revealed improvements in morphometric/ultrastructural parameters compared to the injured group. Sensory analyses suggested that the improvements observed were associated with time progression and not influenced by the treatments. Motor analyses revealed significant improvements in grip strength from the 7th day in the LLLT group and in gait from the 56th day in all treated groups. We concluded that even though the morphological analyses showed improvements with the treatments, they did not influence sensory recovery, and LLLT improved motor recovery.

Using an Attachment System with PEEK Matrices for Single-Implant Overdentures: In Vitro Retention Force.

Single-implant overdentures (SIOs) represent a major biomechanical challenge in terms of prosthetic retention. The Novaloc attachment system has the potential to overcome those challenges when used for SIOs, due to the use of PEEK matrices. This study compared the retentive force of the Novaloc attachment to the traditional Locator system, before and after cyclic insertion-removal cycles. Three Novaloc matrices (white, yellow, and green, corresponding to low, medium, and high retention, respectively) and Locator (medium retention) were tested, totalling four groups. Retentive force was measured using an Imada force gauge before and after 1095 insertion-removal cycles, corresponding to a year of SIO wearing. Retention was tested with the implants angulated at 0, 10, and 20°. Data for the different groups, angles, and cycling periods were tested via linear regression analysis and two-way ANOVA (α = 0.05). Although the Locator system yielded higher retention forces in general, it lost a much higher percentage of retention with cycling. This trend was similar with the three angles, with forces being inversely proportional to the implant angulation. The authors conclude that Novaloc may provide more reliable retention for SIOs due to their higher resistance to insertion-removal cycling.

Palatal brushing for the treatment of denture stomatitis: A multicentre randomized controlled trial.

PURPOSE: To determine the effectiveness of palatal brushing in the treatment of denture-related erythematous stomatitis (DES) in complete denture wearers. METHODS: This two-parallel-arm RCT was conducted in three university clinics in Brazil, Canada, and Chile. Participants (n=77) were randomly allocated to receive (i) instructions for palatal brushing and standard oral/denture hygiene ("intervention"); or (ii) standard oral/denture hygiene instructions only ("control"). Data collection was carried out at the baseline and at 3 and 6 months after intervention. Outcomes included the magnitude of oral Candida carriage and the degree of inflammation of denture-bearing tissues. Groups were compared using generalized estimating equations and chi-square test (α=0.05). RESULTS: Palatal inflammation levels were reduced significantly in the "intervention" compared to "control" group at 6 months (intervention: 70%, control: 40%; chi-square, p=0.04). There was no between-group significant difference in the Candida count from denture and palatal biofilms; however, a subgroup analysis restricted to baseline Candida carriers showed further reduction with the intervention at 6 months. No adversity was observed by trialist or reported by participants. CONCLUSIONS: Including palatal brushing in oral instructions for denture wearers has positive impact on DES-related mucosal inflammation. Thus, our findings endorse the inclusion of palatal brushing in standard oral hygiene instructions to treat DES.

Biomechanical Behavior of Narrow Dental Implants Made with Aluminum- and Vanadium-Free Alloys: A Finite Element Analysis.

Titanium (Ti) alloys used for narrow dental implants usually contain aluminum (Al) and vanadium (V) for improved resistance. However, those elements are linked to possible cytotoxic effects. Thus, this study evaluated the biomechanical behavior of narrow dental implants made with Al- and V-free Ti alloys by the finite element method. A virtual model of a partially edentulous maxilla received single implants (diameter: 2.7 and 2.9 mm; length: 10 mm) at the upper lateral incisor area, with respective abutments and porcelain-fused-to-metal crowns. Simulations were performed for each implant diameter and the following eight alloys (and elastic moduli): (1) Ti-6Al-4V (control; 110 GPa), (2) Ti-35Nb-5Sn-6Mo-3Zr (85 GPa), (3) Ti-13Nb-13Zr (77 GPa), (4) Ti-15Zr (113 GPa), (5) Ti-8Fe-5Ta (120 GPa), (6) Ti-26.88Fe-4Ta (175 GPa), (7) TNTZ-2Fe-0.4O (107 GPa), and (8) TNTZ-2Fe-0.7O (109 GPa). The implants received a labially directed total static load of 100 N at a 45° angle relative to their long axis. Parameters for analysis included the maximum and minimum principal stresses for bone, and von Mises equivalent stress for implants and abutments. Ti-26.88Fe-4Ta reaches the lowest maximum (57 MPa) and minimum (125 MPa) principal stress values, whereas Ti-35Nb-5Sn-6Mo-3Zr (183 MPa) and Ti-13Nb-13Zr (191 MPa) models result in the highest principal stresses (the 2.7 mm model surpasses the threshold for bone overload). Implant diameters affect von Mises stresses more than the constituent alloys. It can be concluded that the narrow implants made of the Ti-26.88Fe-4Ta alloy have the most favorable biomechanical behavior, mostly by mitigating stress on peri-implant bone.

Simultaneous Implant Placement and Sinus Lift Using Leukocyte-Platelet Rich Fibrin: A Retrospective 40-Month Study.

ABSTRACT: The aim of this study was to report the 40-month clinical radiographical outcomes of maxillary sinus floor augmentation using leukocyte-platelet rich fibrin (L-PRF) as a single graft in combination with immediately placed implants. Twenty partially edentulous individuals with missing teeth in the region associated to maxillary sinus were included in this retrospective study. A lateral sinus floor elevation was performed considering a complete wear of the bone wall of the maxillary sinus and immediately placing the implant and filled the maxillary sinus with L-PRF clots as a single graft. After 5 months, all the implants received single screwed implant-supported prostheses. Subsequent evaluation was every 4 months assessing the success rate and biological complications. Two maxillary sinus membrane were perforated and covered with L-PRF clots. The mean bone height gain was 62.6%, observing a 100% of success and that in all the cases achieved at least the implant height. In conclusion, the use of platelet-rich fibrin clot as a single graft biomaterial during the maxillary sinus lift procedure combined with immediate implant placement may be a reliable clinical alternative, even to repair the sinus membrane.

Clinical evaluation of single 4-mm implants in the posterior mandible: A 3-year follow-up pilot study.

STATEMENT OF PROBLEM: Extra-short implants in the posterior mandible can increase the functional surface area and reduce the risk of implant overload. However, reports of treatment using single extra-short implants in the posterior mandible with a midterm follow-up are lacking. PURPOSE: The purpose of this prospective pilot study was to evaluate the clinical behavior of single extra-short 4-mm implants placed in the posterior mandible during a follow-up of 3 years from implant restoration. MATERIAL AND METHODS: A total of 18 participants with a single extra-short 4-mm-long implant placed in the area of the mandibular first molars participated in this pilot study. The survival and success rates of implants, as well as biologic and prosthetic variables, were evaluated during a follow-up of 3 years from implant restoration. RESULTS: The survival rate of the implants was 100%, with no implant or biologic complications recorded. One prosthetic complication (loosening of 1 screw) was observed. CONCLUSIONS: Single extra-short (4 mm) implants in the posterior mandible showed favorable clinical behavior during the first 3-years of follow-up.

Ultra-Thin Veneers: A Current State-of-the-Art

ABSTRACT: Currently, the aesthetic requirements of patients are increasing and they have begun to request more conservative treatments. One alternative to achieve harmonious results is through the indication of ultra-thin veneers. This is considered a conservative technique but the evidence basis for it seems to be limited. The following review attempts to summarize the relevant literature to establish guidelines for clinicians based on scientific evidence regarding the use of ultra-thin veneers. Ultra-thin veneers seem to be a reliable alternative to achieve aesthetic and harmonious results; however, many factors must be considered to ensure correct diagnosis and treatment plan. In addition, the literature is scarce in relation to a consensus on tooth preparation and long-term studies evaluating the success of this type of treatment over time do not exist.

RESUMEN: Actualmente, los requisitos estéticos de los pacientes han aumentando y solicitan tratamientos más conservadores. Una alternativa para lograr resultados armónicos es mediante la indicación de carillas o laminados ultrafinos. Esta se considera una técnica conservadora, pero la base teórica parece ser limitada. La siguiente revisión intenta resumir la literatura relevante para establecer pautas para clínicas basadas en evidencia científica sobre el uso de carillas ultrafinas. Las carillas ultrafinas parecen ser una alternativa confiable para lograr resultados estéticos y armónicos; sin embargo, se deben considerar muchos factores para asegurar un diagnóstico y plan de tratamiento correcto. Además, la literatura es escasa en relación a un consenso sobre la preparación dental y no existen estudios a largo plazo que evalúen el éxito de este tipo de tratamiento a lo largo del tiempo.

Análisis biomecánico en la zona para-radicular de primer molar con y sin la aplicación de micro-osteoperforaciones en mandíbula. Estudio en Elementos Finitos / Para-root zone biomechanical analysis with and without the application of micro-osteoperforations in the jaw: Finite Elements Study

RESUMEN Objetivo: El propósito del presente estudio fue investigar biomecánicamente si el tratamiento con micro-osteoperforaciones (Mops) genera diferencias de desplazamiento y de tensiones a nivel óseo cuando se aplica una carga ortodóncica, mediante el uso de análisis de elementos finitos. Material y Método: Un modelo de mandíbula dentada donde se eliminó el segundo premolar fue utilizado para el análisis. Posteriormente, se dividieron en 3 muestras dependiendo de la posición de las Mops: 1) Sin Mops (control); 2) Mops 1 mm adyacentes al primer molar; 3) Mops a 4 mm del molar. Para la simulación, se aplicó una carga estática horizontal de 150 gr (1,5N), simulando un resorte cerrado de Nitinol, tanto a nivel molar en dirección mesial como a nivel interproximal entre canino e incisivo lateral en dirección distal. Resultados: A pesar que se observó una ligera tendencia a aumentar el desplazamiento del molar con la presencia de Mops, no existieron mayores variaciones en relación a las magnitudes de desplazamiento ni tensiones entre los diferentes modelos. Conclusiones: Desde el punto de vista biomecánico no existen diferencias evidentes en los valores de tensiones ni de desplazamiento entre los modelos analizados.

ABSTRACT: Objective: The purpose of the present study was to biomechanically investigate if the treatment with micro-osteoperforations (Mops) generates displacement and tensions differences at bone level when an orthodontic load is applied, through the use of finite element analysis. Material and Method: A toothed jaw model where the second premolar was removed was used for the analysis. Subsequently, they were divided into 3 samples depending on the position of the Mops: 1) Without Mops (control); 2) Mops adjacent 1 mm to the first molar; 3) Mops 4 mm to molar. To simulate a closed Nitinol spring, an horizontal static load of 150 gr (1.5N) was applied, both at molar level in the mesial direction and at interproximal level between the canine and the lateral incisor in the distal direction. Results: Although a slight tendency to increase the displacement of the molar with the presence of Mops was observed, there were no major variations in relation to the magnitudes of displacement or tensions between the different models. Conclusions: From the biomechanical point of view, there are no obvious differences in the values of stresses or displacement between the models analyzed.

A new insight of Platelet-Rich Fibrin clots morphology and their elemental composition.

This study analyzed the architecture of Platelet-Rich Fibrin (PRF) clots and assessed their elemental composition in order to provide new insight into this biomaterial. Five surplus PRF clots (2,700 RPM, 12 min.) donated by patients (63.6 ±â€¯12.3 years old) were prepared for use in dental clinical procedures. The internal three-dimensional morphology of the red zones and the thirds of the yellow zones of the clots were analyzed by Variable Pressure Scanning Electron Microscope (VPSEM) after sample preparation by two methods: 1. Fixation (2.5% gluataraldehyde); and 2. Fixation with subsequent partial removal of extracellular elements (8 N, HCl). Semi-quantitative elemental analysis was performed by energy-dispersive X-ray spectrometry (EDX). VPSEM analysis showed erythrocytes in both the red zone and the yellow zone, which consisted mainly of fibrin. Removal of extracellular elements enriched the morphology of both zones; the organization of the fibrin was observed to differ in the thirds of the yellow zone, with increasing density and organization to distal. The elements that compose organic substances (C-Carbon, N-Nitrogen, O-Oxygen, Na-Sodium and P-Phosphorus) and halogens (Cl-Chloride and S-Sulfur) were detected; the highest concentrations were of C, followed by O (p < 0.05), in the proximal region of the fibrin. The results of the present study suggest organization of fibrin in the PRF clot, and also reveal the distribution of the elements present in the different regions of the clot. Improved understanding of these characteristics may favor the use of this biomaterial by increasing its efficiency and functionality.

Comparison of morphological quantitative characteristics of the newly formed alveolar bone after the application of demineralized bone matrix and cortical bone allografts / Comparación de las características morfológicas cuantitativas del hueso alveolar recién formado después de la aplicación de matriz ósea desmineralizada y aloinjertos de hueso cortical

The allografts were used to obtain sufficient alveolar bone tissue for proper dental implant placement. The objective of the present study was to evaluate the morphological and quantitative characteristics (cellular and collagen densities) of the newly formed alveolar bone with the application of cortical bone (CB) and demineralized bone matrix (DBM) allografts. Six samples of alveolar bone tissue from 5 patients (50 ± 6.3 years) were obtained after 6 months of application of the allografts and immediately before the placement of the dental implants. The samples were fixed (buffered formaldehyde, pH7.2), decalcified (EDTA 10 %) and histologically processed (HE and Picro-Sirius) for histologic analysis. Morphological analysis revealed presence of osteocytes and trabeculae in neoformed bone tissue near the allografts and absence of inflammatory and allergic cells; the remnants of CB were located mainly in the periphery of the bone tissue and the remnants of DBM were more incorporated into the tissue. Osteogenitor cells were observed around the remaining material. The cell density was not modified in newly formed bone tissue with the application of both allografts as compared to mature bone tissue. The density of the type I and III collagens present in the osteoids interspersed with the remainder of the materials showed a tendency to increase in the samples treated with DBM. It was concluded that by the histological characteristics observed both grafts were biocompatible, however the bone treated with DBM presented better incorporation and a tendency of increase of the collagen content in the remnant region of the allografts.

Los aloinjertos son utilizados para obtener tejido óseo alveolar apropiado para la colocación correcta del implante dental. El objetivo de este trabajo fue evaluar las características morfológicas y cuantitativas (densidades celulares y de colágeno) del hueso alveolar recién formado con la aplicación de aloinjertos de hueso cortical (CB) y matriz desmineralizada de hueso (DBM). Seis muestras de tejido óseo alveolar fueron obtenidas de 5 pacientes (50 ± 6,3 años) después de 6 meses de aplicación de los aloinjertos e inmediatamente antes de la colocación de los implantes dentales. Las muestras fueron fijadas (formaldehído tamponado, pH 7,2), descalcificadas (EDTA al 10%) y procesadas histológicamente (HE y Picro-Sirius) para el análisis histológico. El análisis morfológico reveló la presencia de osteocitos y trabéculas en el tejido óseo neoformado cerca de los aloinjertos y la ausencia de células inflamatorias y alérgicas; los remanentes de CB se ubicaron principalmente en la periferia del tejido óseo y los remanentes de DBM se incorporaron más en el tejido. Se observaron células osteogenitoras alrededor del material restante. La densidad celular no se modificó en el tejido óseo recién formado con la aplicación de ambos aloinjertos en comparación con el tejido óseo maduro. La densidad de los colágenos de tipo I y III presentes en los osteoides intercalados con el resto de los materiales mostró una tendencia a aumentar en las muestras tratadas con DBM. Se concluyó que, debido a las características histológicas observadas, ambos injertos fueron biocompatibles, sin embargo, el hueso tratado con DBM presentó una mejor incorporación y una tendencia al aumento del contenido de colágeno en la región remanente de los aloinjertos.

Effect of Different Framework Materials in Implant-Supported Fixed Mandibular Prostheses: A Finite Element Analysis.

PURPOSE: To evaluate the biomechanical behaviors of different framework materials in implant-supported fixed mandibular prostheses using three-dimensional (3D) finite element analysis. MATERIALS AND METHODS: A model of a severely resorbed edentulous mandible was obtained from a tomography database. Morse taper-connection implants and multi-unit abutments were cut with an electro-erosion machine and scanned using a 3D scanner. The implants were positioned on the model at the bone level and distributed equally to support a fixed complete prosthesis. The simulations were divided into six groups according to the framework material: titanium (Ti); cobalt-chromium (Co-Cr); zirconia (ZrO2); polyether ether ketone (PEEK); carbon fiber-reinforced polyether ether ketone (CFR-PEEK); and polymethyl methacrylate (PMMA). The resultant load applied was obtained from the masseter, temporal, lateral, and medial pterygoid muscles. The principal stresses and von Mises equivalent stresses were analyzed and compared among the framework materials, and the results were described both quantitatively and qualitatively. RESULTS: PEEK and PMMA frameworks showed the highest total deformation values, showing decreases of von Mises stresses in the frameworks, implants, and abutments, but with a high tensile stress in the trabecular bone that achieved critical values. CFR-PEEK frameworks achieved their failure limit, whereas the ZrO2, Co-Cr, and Ti frameworks exhibited principal stresses in the bone region within physiologic limits. CONCLUSION: From a biomechanical point of view, the Ti, Co-Cr, and ZrO2 frameworks demonstrated the most favorable outcomes.

Sinus Floor Augmentation by Intraoral Endoscopic Approach for Biomaterial Study in a Rabbit Model.

AIM: To develop a new surgical model for sinus floor augmentation (SFA) in rabbit for experimental purposes. MATERIALS AND METHODS: Eight adult rabbits were used, two for a surgical design using the anatomical dissection study, and the other six for an endoscopically assisted intraoral approach of SFA unilaterally, creating a subantral space where an allograft biomaterial was deposited. SFA was verified through cone-beam computerized tomography. Healing, weight, food, feces, and behavior were evaluated for 4 weeks post-operatively. RESULTS: All animals survived. There was no bleeding or infection; inflammation was mild. No changes were observed in terms of feeding, weight, feces, or behavior. Tissue healing was normal. CONCLUSION: This model is a refinement of the experimental technique and is a real option for SFA, without compromising animal morbidity because of its conservative design. The minimally invasive approach with endoscopic assistance reduces bias and improves surgical predictability.

Assessment of maxillary premolar region in relation to maxillary sinus floor and buccal bone plate: a cone beam computed tomography study / Evaluación de la región premolar maxilar en relación con el piso del seno maxilar y la tabla osea vestibular: estudio de tomografía computarizada de haz cónico

The maxillary sinus floor location and the buccal bone plate are factors to be considered in the long-term success with implant treatments mainly in the premolar region. the aim of this study was to establish morphometric characteristics of the buccal cortical bone (BCB) thickness of maxillary premolars and its relation to maxillary sinus floor through CBCT. In this study 350 first and second maxillary premolars were analyzed from 110 CBCT images and the buccal cortical bone (BCB) was measured in a coronal view at the major axis level of each premolar. In addition, in 200 first and second maxillary premolars CBCT images were measured the distance from premolar apex to maxillary sinus floor (MSF) in both frontal and sagittal plane. The type of relationship between the apex and MSF was classified according to Ok et al. (2014). The second premolar was observed with higher values of BCB (p<0.001). In first premolar, higher values were observed in the male sex (p>0.05). In second premolar, only significantly higher values were observed in the male sex in MA-MB-MC (p>0.05). Regarding to MSF and its relation to premolar roots, it was observed that 10 % of the sample was classified as type I, 19 % as type II, 55.5 % as type III and 15.5 % as type IV. The BCB of the upper premolar region is thicker in the apical region and decreases toward the coronal region. Almost 50 % of apex of second premolars are closely and risky related MSF (Type I and II).

La localización del piso del seno maxilar (PSM) y la tabla ósea vestibular (TOV) son factores a considerar en el éxito a largo plazo de los tratamientos de implante dental en la región premolar. El objetivo de este estudio fue establecer características morfométricas del grosor de la TOV en los premolares maxilares y su relación con el PSM a través de CBCT. Se analizaron 350 primeros y segundos premolares en 110 CBCT y la TOV fue medida en vista coronal en el eje axial mayor de cada premolar. Además en 200 primeros y segundos premolares maxilares se midió la distancia desde el ápice del diente hasta el PSM en el plano sagital y frontal. El tipo de relación entre el ápice y el PSM se clasificó según Ok et al. (2014). El Segundo premolar obtuvo los mayores valores de grosor de TOV (p<0.001). En primeros premolares se observaron valores altos en el género masculino (p>0.05). En segundos premolares solo se encontraron valores significativamente altos en el género masculino en MA-MB-MC (p>0.05). En la relación con el PSM y ápices de raíces de premolares, el 10% de la muestra se clasificó como tipo I, el 19% como tipo II, el 55,5% como tipo III y el 15.5% como tipo IV. En conclusión la TOV de la región premolares superior es más grueso en la zona apical, decreciendo hacia la zona coronal. Alrededor del 50% de los ápices de raíces de premolares maxilares están cercanas y en relación de riesgo con el PSM (tipo I y II).

Platelet-rich fibrin and collagen membrane in the preservation of the alveolar bone: Feasibility of the elemental inorganic composition and scanning electron microscopy analysis.

The success of dental implants is related to the amount, quality, and composition of the alveolar bone. The placement of platelet-rich fibrin (PRF) clot associated with a resorbable collagen membrane (RCM) in a postextraction alveolus is a technique used for ridge preservation. This case report study analyzed the ultrastructural characteristics of cross-sectioned alveolar bone that received PRF and RCM using scanning electron microscopy and the inorganic composition using "energy dispersive X-ray spectrometry," in order to explore the feasibility of this method to clinical studies. Three alveolar bone samples from two male patients (37 and 58 years old), obtained in the procedure of placing the dental implant, were analyzed. Two bone samples previously received PRF and RCM (M37 and M58), the third sample represented a physiological bone formation without treatment (M37-control). The bone sample M37 showed irregularly shaped islets of calcified material intermingled with connective tissue. The other samples, from the 58-year-old patient with PRF and RCM (M58); and the other untreated bone sample from the same 37-year-old patient (M37-control) showed similar ultrastructural morphology with trabecular conformation without islets agglomerations. The inorganic composition analysis showed higher concentrations of calcium and phosphorus in both samples treated with PRF and RCM in comparison to the untreated bone sample. The Ca/P ratio was higher in the M37 sample compared to the others samples. The results showed morphology and inorganic composition differences among the treatments used, suggesting that this method is feasible to analyze parameters of the alveolar bone tissue.

Autologous Fibrin Glue With Collagen Carrier During Maxillary Sinus Lift Procedure.

This study aimed to describe the use of autologous fibrin glue (AFG) with a collagen carrier during maxillary sinus lift procedures with immediate implants during 3 years of follow-up. Twelve patients who had lost their teeth in the region associated to maxillary sinus, with a bone remnant 3 to 5 mm in height, were selected to perform a maxillary sinus augmentation with AFG and collagen membrane, placing the implant immediately. After 5 months, the implants were connected and rehabilitated. The patients were followed-up for a 3-year period, being evaluated every 6 months. At the end of the 3-year follow-up period, 100% implant success was observed, with a mean of bone augmentation of 7.75 mm. Three maxillary sinus membranes were perforated and healed by using AFG and collagen membrane without identify any complication during the follow-up period. Finally, the use of collagen carrier combined with AFG as a filling material during the maxillary sinus lift procedure may be a low-cost and reliable alternative that allows bone formation.

Oral Applications of Cyanoacrylate Adhesives: A Literature Review.

Cyanoacrylate adhesives have been used in medicine and dentistry with some controversial opinions. The aim of this review was to summarize the relevant literature regarding the use of cyanoacrylate adhesives for oral wounds during dental and surgical procedures, with focus on the applications, indications, advantages, and disadvantages. In conclusion, in vivo and clinical studies have demonstrated in the last few years convincing results regarding the safety, efficacy, ease of application, and feasibility of all types of cyanoacrylate adhesives used in intra- and extraoral procedures.

Growth factors expression and ultrastructural morphology after application of low-level laser and natural latex protein on a sciatic nerve crush-type injury.

The effects of low-level laser therapy (LLLT) and natural latex protein (F1, Hevea brasiliensis) were evaluated on crush-type injuries (15kg) to the sciatic nerve in the expressions of nerve growth factor (NGF) and vascular endothelium growth factor (VEGF) and ultrastructural morphology to associate with previous morphometric data using the same protocol of injury and treatment. Thirty-six male rats were allocated into six experimental groups (n = 6): 1-Control; 2-Exposed nerve; 3-Injured nerve; 4-LLLT (15J/cm2, 780nm, 30mW, Continuous Wave) treated injured nerve; 5-F1 (0,1mg) treated injured nerve; and 6-LLLT&F1 treated injured nerve. Four or eight weeks after, sciatic nerve samples were processed for analysis. NGF expression were higher (p<0.05) four weeks after in all injured groups in comparison to Control (Med:0.8; Q1:0; Q3:55.5%area). Among them, the Injured (Med:70.7; Q1:64.4; Q3:77.5%area) showed the highest expression, and F1 (Med:17.3; Q1:14.1; Q3:21.7%area) had the lowest. At week 8, NGF expressions decreased in the injured groups. VEGF was expressed in all groups; its higher expression was observed in the injured groups 4 weeks after (Injured. Med:29.5; F1. Med:17.7 and LLLT&F1. Med:19.4%area). At week 8, a general reduction of VEGF expression was noted, remaining higher in F1 (Med:35.1; Q1.30.6; Q3.39.6%area) and LLLT&F1 (Med:18.5; Q1:16; Q3:25%area). Ultrastructural morphology revealed improvements in the treated groups; 4 weeks after, the F1 group presented greater quantity and diameter of the nerve fibers uniformly distributed. Eight weeks after, the F1 and LLLT&F1 showed similar characteristics to the non-injured groups. In summary, these results and our previous studies indicated that F1 and LLLT may favorably influence the healing of nerve crush injury. Four weeks after nerve injury F1 group showed the best results suggesting recovery acceleration; at 8th week F1 and LLLT&F1 groups presented better features and higher vascularization that could be associated with VEGF maintenance.

Influence of transmucosal height in abutments of single and multiple implant-supported prostheses: a non-linear three-dimensional finite element analysis.

The aim of this study was to analyze the influence of three different transmucosal heights of the abutments in single and multiple implant-supported prostheses through the finite element method. External hexagon implants, MicroUnit, and EsthetiCone abutments were scanned and placed in an edentulous maxillary model obtained from a tomography database. The simulations were divided into two groups: (1) one implant with 3.75 × 10 mm placed in the upper central incisor, simulating a single implant-supported fixed prosthesis with an EsthetiCone abutment; and (2) two implants with 3.75 × 10 mm placed in the upper lateral incisors with MicroUnit abutments, simulating a multiple implant-supported prosthesis. Subsequently, each group was subdivided into three models according to the transmucosal height (1, 2, and 3 mm). A static oblique load at an angle of 45 degrees to the long axis of the implant in palatal-buccal direction of 150 and 75 N was applied for multiple and single implant-supported prosthesis, respectively. The implants and abutments were assessed according to the equivalent Von Mises stress analyses while the bone and ceramics were analyzed through maximum and minimum principal stresses. The total deformation values increased in all models, while the transmucosal height was augmented. The transmucosal height of the abutments influences the stress values at the bone, ceramics, implants, and abutments of both the single and multiple implant-supported prostheses, with the transmucosal height of 1 mm showing the lowest stress values.

Anatomic relationships of mandibular canal: a cone beam CT study / Relaciones anatómicas del canal mandibular: un estudio en tomografías computarizadas de haz de cono

SUMMARY: It is critical to know the precise location and configuration of the mandibular canal (MC) to avoid damages in the alveolar inferior nerve during an invasive dental treatment. The aim of this study was to provide anatomic relationships of the mandibular canal in its entire pathway related to cortical walls and dental roots to serve as basic knowledge for dental clinical procedures performed in this area. We analyzed 50 CBCT images assessing the specific location of MC at the retromolar space as related to inferior teeth roots. Data were analyzed by side using descriptive statistics (median: mean [M], standard deviation [SD], 95 % confidence interval: lower endpoint [IC] and upper endpoint [IC']). The MC length and pathway were measured from the mandibular foramen up to the mental foramen. MC was closer from lingual cortical than buccal at the retromolar space as well the distal root of the second molar and the root of the second premolar are closest to MC. A mean length for the MC of 70.8 (±5.3 mm) for the right side and 71 (±5.8 mm) for the left side were observed. In conclusion, it is critical for clinicians to know three-dimensionally the topographic relationships between the inferior teeth roots and the mandibular canal before proceeding to any invasive dental or surgical procedure at this region.

RESUMEN: Es crítico conocer la ubicación exacta y la configuración del canal mandibular (MC) para evitar daños en el nervio inferior alveolar durante un tratamiento dental invasivo. El objetivo de este estudio fue proporcionar relaciones anatómicas del MC en toda su trayectoria relacionada con paredes corticales y raíces dentales para servir como un conocimiento básico para los procedimientos clínicos dentales realizados en esta región. Se analizaron 50 imágenes CBCT evaluando la localización específica del MC en el espacio retromolar, así como las raíces de los dientes inferiores. Los datos se analizaron por lado, utilizando estadística descriptiva (mediana: media [M], desviación estándar [SD], 95 % intervalo de confianza: punto final inferior [IC] y extremo superior [IC]). La longitud y vía del conducto mandibular se midieron desde el foramen mandibular hasta el foramen mentoniano. El MC estaba más cerca de la cortical lingual que bucal en el espacio retromolar, así como la raíz distal del segundo molar y la raíz del segundo premolar están más cerca del MC. Se observó una longitud media para el MC de 70,8 (± 5,3 mm) para el lado derecho y de 71 (± 5,8 mm) para el lado izquierdo. En conclusión, es fundamental que el clínico conozca tridimensionalmente las relaciones topográficas entre las raíces de los dientes inferiores y el conducto mandibular antes de proceder a cualquier procedimiento invasivo dental o quirúrgico en esta región.

Quantitation of Mandibular Symphysis Bone as Source of Bone Grafting: Description in Class I and Class III Skeletal Conditions.

The aim of this study was to quantify the cortical and cancellous bone in the mandibular symphysis and relate it to the teeth and to the skeletal class. A descriptive study was conducted using cone beam computerized tomography (CBCT). Class I and class III subjects were included, defined according to dental occlusion and cephalogram results. Linear measurements were taken on the CBCT of the mandibular canines, lateral incisors, and central incisors, where the analysis was related to the axial and apical axes considering the bone in relation to the dental area. With previous definitions, an observer took 2 measurements of the height of the mandibular symphysis, cortical bone of the buccal and lower region, and thickness of cancellous bone at different levels; the correlation coefficient between the first and second measurement was 0.99 and presented P = .001. The results were analyzed with analysis of variance and Tukey's honest significant difference test, with P < .05 being statistically significant. The symphysis height was significantly greater in class III subjects. The cortical bone was an average 1.67 ± 0.44 mm in vertical distance in the skeletal class I group and 1.74 ± 0.47 mm in the class III group. The cancellous bone had an average width of 5.03 ± 1.94 mm in the skeletal class I group and 4.74 ± 2.05 mm in the class III group. It was observed that cancellous bone was significantly thicker at the incisor level than at the canine level. There were anatomical differences between skeletal class I and class III subjects, although the clinical significance may be questionable. With the values from these analyses, it may be concluded that there are no significant differences in quantitation of the cortical and cancellous bone in the anterior mandibular symphysis.