Effects of premature contact in maxillary alveolar bone in rats: relationship between experimental analyses and a micro scale FEA computational simulation study.

OBJECTIVE: The aim of the investigation was to evaluate the maxillary alveolar bone morphology, bone architecture, and bone turnover in relation to the mechanical strain distribution in rats with dental premature contact. MATERIALS AND METHODS: Fifty 2-month-old male Wistar rats were used. The premature contact group (N=40) received a unilateral (right side) resin cementation on the occlusal surface of the upper first molar. The animals were distributed in 4 subgroups according to the periods of euthanasia: 7, 14, 21, and 28 days after cementation (N=10, for each period). For the control group (N=10), the teeth were kept without resin, featuring a normal occlusion. The pieces including the upper first molars, alveolar bone, and periodontal tissue were processed to histological and immunohistochemical evaluation of RANK-L and TRAP protein expression. A three-dimensional bone microarchitecture analysis was performed, where the heads of animals were scanned using microtomography and analyzed using CT-Analyser software (Bruker, Kontich, Belgium). In the computer simulation by finite element analysis, two micro-scaled three-dimensional finite element models of first molar and dentoalveolar tissues were constructed, in representation of control and premature contact groups, using Materialise MIMICS Academic Research v18 (Materialise, Leuven, Belgium). The analysis was set to simulate a maxillary molar biting during the power stroke phase. The total deformation, equivalent strain, and minimum principal strain distribution were calculated. RESULTS: The expression of RANK-L and TRAP presented higher positive ratio in the 7-day period compared to the control group. The three-dimensional morphometry showed decrease of bone volume in the premature contact, with significant values between the control and the 7-day and 14-day groups (P = 0.007). In FEA, the premature contact model presented a uniform compressive strain distribution in the alveolar bone crest compared to a non-uniform compressive strain distribution in the control model. CONCLUSIONS: The results from FEA, 3D bone microarchitecture, and histological and immunohistochemical analyses showed that a model with dental traumatic occlusion resulted in changes of alveolar bone mechanobiology and, consequently, its morphology. CLINICAL RELEVANCE: These results could be applied in dental treatment planning bringing biological and mechanical feedback to provide an effective mechanism to obtain physiological bone loss responses. Furthermore, this association between experimental and computational analyses will be important to figure out the alveolar bone response to mechanical stimulation in different clinical conditions.

Green tea extract rich in epigallocatechin gallate impairs alveolar bone loss in ovariectomized rats with experimental periodontal disease.

Periodontal disease and osteoporosis are characterized by bone resorption, and researchers have shown an association between these two diseases through increasing loss of systemic bone mass and triggering alveolar bone loss. Green tea is a common and easily accessible beverage, and evidences show that flavonoid epigallocatechin gallate (EGCG) could decrease bone loss in pathologies such as osteoporosis and periodontal disease. In order to verify its possible effects and apply them in the treatment and prevention of these diseases, this investigation aimed to evaluate the influence of green tea extract (GTE) on bone metabolism of ovariectomized rats after experimental periodontal disease (EPD) by histological, morphological and microtomographic parameters. Wistar female rats were divided into Sham, Sham + EPD, Sham + EPD + GTE, OVX, OVX + EPD and OVX + EPD + GTE groups. Immediately after surgery, gavage administration of 50 mg/kg of green tea extract (GTE) was performed for 60 days, with subsequent induction of periodontal disease by ligature 15 days before euthanasia. Mandible and femur samples were collected for histological, morphometric and microtomographic analysis. The results were analysed by means of statistical software with significance set at 5%. Histological and morphometric analysis showed a significant decrease in alveolar and femoral trabecular bone loss in groups that received GTE. Microtomographic results showed that trabecular thickness and bone surface density values in alveolar bone interradicular septum of the OVX + EPD + GTE groups were similar to the Sham group. The results obtained suggest that green tea extract may improve bone metabolism in osteoporotic rats with periodontal disease.

Resorptive potential of impacted mandibular third molars: 3D simulation by finite element analysis.

OBJECTIVES: Previous studies have suggested a relationship between resorption in second molars and pressure from the eruptive force of the third molar. The aim of this study was to simulate functional forces in a mandible model by means of finite element analysis and then assess the biomechanical response produced by impacted third molars on the roots of the second molar. MATERIALS AND METHODS: A cone beam computed tomography scan presenting an impacted mandibular third molar was segmented (Mimics V17 software). The modeling process was performed using the reverse engineering technique provided by the Rhinoceros 3D 5.0 software. The third molar position was changed in order to produce different inclinations of the impacted tooth. Bite forces were simulated to evaluate total deformation, the equivalent von Mises stress, minimum principal stress on hard tissue, and equivalent elastic strain on soft tissue. RESULTS: Areas of high energy dissipation and compression stress were detected in the second molar root, independently of the inclination of the impacted third molar. In general, the horizontal position was the situation in which major stress and the amount of deformation occurred in the second and third molar regions. CONCLUSION: Impacted third molars in close proximity with the adjacent tooth can generate areas of compression concentrated at the site of contact, which suggests an involvement of mechanical factors in the triggering of resorption lesions. CLINICAL RELEVANCE: The results of these computational experiments contribute to the understanding of the triggering and progression of resorptive lesions in the adjacent second molar.

Raloxifene but not alendronate can compensate the impaired osseointegration in osteoporotic rats.

OBJECTIVES: Alendronate and raloxifene, a bisphosphonate and a selective estrogen modulator, respectively, are established osteoporosis therapies. Current evidence suggests that simultaneous application of osteoporosis therapies modulates osseointegration. However, alendronate shows inconsistent findings and raloxifene has not been studied comprehensively. This study aimed to evaluate the bone dynamics and molecular and microstructural features at the peri-implant bone interface in osteoporotic rats. MATERIALS AND METHODS: Thirty female rats underwent ovariectomy and were fed a diet low in calcium and phosphate and treated with alendronate or raloxifene for 30 days or underwent fictional ovariectomy surgery (SHAM) prior to implant insertion in the tibia; osteoporosis therapies continued thereafter. After 42 days, peri-implant bone was evaluated by histometric and micro-CT analysis. Fluorochrome incorporation and gene expression was determined to evaluate bone turnover. RESULTS: We report here that alendronate had no impact on bone-to-implant contacts and the mineral apposition rate. The RANKL/OPG ratio and local bone volume, however, were increased compared to the untreated osteoporotic rats. Even though signaling to bone resorption activity through RANKL production was observed in the alendronate group, the blockade of bone resorption activity that occurs in decorrence to alendronate activity took place and resulted in an increase in bone volume. Raloxifene significantly increased osseointegration in osteoporotic rats, as indicated by bone-to-implant contacts, mineral apposition, and local bone volume. Raloxifene, however, had no considerable impact on the RANKL/OPG ratio compared to untreated osteoporotic rats. As expected, the SH group showed higher bone-to-implant contacts and mineral apposition rates than the untreated osteoporotic rats. CONCLUSIONS: These findings suggest that raloxifene but not alendronate can compensate for the impaired osseointegration in osteoporotic rats. CLINICAL RELEVANCE: Regarding the superiority of raloxifene observed in the improvement of bone dynamics response, this statement suggests that raloxifene could be a good option for osteoporosis patients in oral rehabilitation procedures.

Finite-element analysis of 3 situations of trauma in the human edentulous mandible.

PURPOSE: Maxillofacial trauma resulting from falls in elderly patients is a major social and health care concern. Most of these traumatic events involve mandibular fractures. The aim of this study was to analyze stress distributions from traumatic loads applied on the symphyseal, parasymphyseal, and mandibular body regions in the elderly edentulous mandible using finite-element analysis (FEA). MATERIALS AND METHODS: Computerized tomographic analysis of an edentulous macerated human mandible of a patient approximately 65 years old was performed. The bone structure was converted into a 3-dimensional stereolithographic model, which was used to construct the computer-aided design (CAD) geometry for FEA. The mechanical properties of cortical and cancellous bone were characterized as isotropic and elastic structures, respectively, in the CAD model. The condyles were constrained to prevent free movement in the x-, y-, and z-axes during simulation. This enabled the simulation to include the presence of masticatory muscles during trauma. Three different simulations were performed. Loads of 700 N were applied perpendicular to the surface of the cortical bone in the symphyseal, parasymphyseal, and mandibular body regions. The simulation results were evaluated according to equivalent von Mises stress distributions. RESULTS: Traumatic load at the symphyseal region generated low stress levels in the mental region and high stress levels in the mandibular neck. Traumatic load at the parasymphyseal region concentrated the resulting stress close to the mental foramen. Traumatic load in the mandibular body generated extensive stress in the mandibular body, angle, and ramus. CONCLUSIONS: FEA enabled precise mapping of the stress distribution in a human elderly edentulous mandible (neck and mandibular angle) in response to 3 different traumatic load conditions. This knowledge can help guide emergency responders as they evaluate patients after a traumatic event.

Cross-sectional study of correlation between mandibular incisor crowding and third molars in young Brazilians.

OBJECTIVES: The aim of this study was to evaluate transversally the clinical correlation between lower incisor crowding and mandible third molar. STUDY DESIGN: Three hundred healthy volunteers (134 male and 166 female), aged 20.4 (±2.4) years-old were submitted to a complete clinical examination and filled up a questionnaire about gender, age, total teeth number and presence or absence of superior and inferior third molar. After a recent panoramic radiography were evaluated. The multiple logistic regression showed that none of the studied factors influenced the mandibular incisor crowding. RESULTS: The proportion of both molars present or both absent was higher than the other conditions (Chi-square, p<.0001). The multiple logistic regression showed that any of the studied factors, influenced (p>.05) the mandibular incisor crowding. Despite the statistical significance, wear orthodontics appliances showed a little correlation (odds ratios < 1.0) in the mandibular incisor crowding. CONCLUSION: Presence of maxillary and/or mandibular third molars has no relation with the lower incisor crowding.

Fenestration and Dehiscence in Human Maxillary Alveolar Bone: An In Silico Study Using the Finite Element Method.

INTRODUCTION: Fenestration and dehiscence are alveolar bone defects. Although not considered a pathology, these alveolar bone defects end up influencing dental treatment, such as surgeries, mainly periodontal, and therefore must be considered during treatment planning. However, currently, little is known about the biomechanical origin of these bone formations. The aim of the study was to use the finite element method (FEM) to test hypotheses of predictive factors for fenestrations and dehiscence in human alveolar bone. METHODS: A FEM simulation of the action of functional, parafunctional, and orthodontic occlusal loads on the upper central incisor and upper canine was performed. For the simulation, a three-dimensional model of an adult human skull, fully dented and with intact bone structure, was constructed from computed tomography images. The buccal alveolar bone lamina was evaluated considering the calculation of equivalent stresses, as well as maximum principal stresses. RESULTS: The action of functional and parafunctional forces on the incisal edges and the orthodontic force on the buccal face of the upper central incisor and upper canine teeth generated tensions at different levels of magnitude in the buccal bone lamina, varying in regions, at all levels of strength. Changing levels of force magnitude resulted in variations in relation to the level of deformation. CONCLUSION: The computational simulation using the FEM was able to identify a difference in stress in the alveolar bone tissue in each of the applied forces. The difference in stresses obtained may suggest the formation of dehiscence or fenestration in the region studied.

Histometric analysis of bone repair in bone-implant interface using a polylactic/polyglycolic acid copolymer associated with implants in rabbit tibia.

The purpose of this study was to evaluate the association of the combination of polylactic/polyglycolic acid around implants installed with and without primary stability through the histometric analysis of bone-implant interface. We used male rabbits, each of which received 2 titanium implants in each tibial metaphysis. The animals were divided into 4 groups: control with primary stability (CPS), control without primary stability (C), polymer with primary stability (PPS), and polymer without primary stability (P). Euthanasia was performed at postoperative days 40 and 90. The pieces were embedded in resin, sectioned, scraped, and stained with alizarin red and Stevenel blue. Histometric analysis evaluated the linear extension of contact between the bone and implant surface on the implant collar (CIC) and contact between the bone and implant surface on the first thread (CFT). Also evaluated was the area of newly formed bone (ANB) in the first thread. The results showed that there was new bone formation in all groups and during all periods. At 40 days, the ANB was higher in the PPS group than in the P group (P < .001); the CFT was statistically higher in the CPS group than the PPS group (P < .001) and was higher in the CPS group than the C group (P < .001). At 40 and 90 days, the CIC was higher in the P group than in the C group (P < .001). In conclusion, the copolymer had biocompatibility, enhanced bone healing, and presented osteoconductive properties, thus raising the contact between bone and implant, even without primary stability.

A Different Pattern of Arrangement of the Risorius Muscle Fibers: A Case Report.

The risorius is a very thin muscle and is one of the superficial muscles of facial expression, which is reported as being inconstant, as it is absent in most people, and is a unique muscle; once it has no bony origin. The study aimed to report a different pattern of arrangement of the risorius muscle fibers. During a routine Anatomy class, a different pattern of arrangement of the risorius muscles fibers was found from the observation of an adult (around 40 years old) male cadaver hemiface (right side). After dissections, it was possible to note that the arrangement of the risorius muscle fibers on the surface of the masseteric fascia was formed in different arrangements formed in two bands. In conclusion, the risorius muscle fibers are not always easily distinguishable, and detailed knowledge of their different morphological arrangement is essential when planning and performing facial procedures.

Chronic exposure to lead acetate promotes changes in the alveolar bone of rats: microstructural and physical-chemical characterization.

There are a few data relating to the effects of lead (Pb) exposure on the alveolar bone, which has very distinct morphophysiological characteristics and is of great importance in the oral cavity. In this context, the aim of this study was to investigate the changes promoted after long-term exposure to Pb in the microstructure of the alveolar bone of rats. Twenty adult Wistar rats were exposed to 50 mg/kg/day of lead acetate for 55 days. These animals were euthanized and had their mandible removed. Each mandible was divided into hemimandibles, and the alveolar bone was used for bone lead quantification, crystallinity analysis, microstructure evaluation by the percentage of bone volume (BV/TV), number of trabeculae (Tb.N), thickness of the trabecular (Tb.Th), and trabecular space (Tb.Sp). Morphometric analysis of the exposed root area was also performed. Long-term exposure to Pb resulted in high levels of Pb in the alveolar bone but showed no changes in the organization of crystallinity. The microstructural analyses showed a reduction of BV/TV, Tb.Th, and Tb.N and increase of Tb.Sp parameters, resulting in an increase in the exposed root area and an alveolar bone loss in height. The findings of this study reveal the ability of Pb to alter the alveolar bone microstructure after long-term exposure to the metal, possibly due to changes in tissue homeostasis, contributing to the reduction of bone quality.

ß-catenin and Its Relation to Alveolar Bone Mechanical Deformation - A Study Conducted in Rats With Tooth Extraction.

The aim of this study was to analyze the relationship between alveolar bone deformation and ß-catenin expression levels in response to the mechanical load changed by dental extraction in adult rats. Twenty-four male rats (Rattus norvegicus albinus), Wistar linage, at 2 months of age, were used. The right upper incisor tooth was extracted, and euthanasia occurred in periods 5 (n = 6), 7 (n = 6), and 14 (n = 6) days after Day 0. In the control group (n = 6), the dentition was maintained. The euthanasia occurred within 14 days after day 0. After euthanasia, the rats of all groups had their left jaw with tooth removed and separated in the middle. The pieces were undergone routine histological processing and then the immunohistochemical marking were performed to label expression of the primary ß-catenin antibody, which was evaluated by qualitative and quantitative analysis. One head by each group (control and experimental) was submitted to computerized microtomography. After the three-dimensional reconstruction of the skull of the rat in each group, the computational simulation for finite elements analysis were performed to simulate a bite in the incisors. In finite element analysis, the strain patterns were evaluated after the application of bite force. The results were analyzed considering the areas in which changes in the amount of deformations were detected. The action of the bite force in the experimental condition, resulted in a uniform distribution of the amount of deformations, in addition to lower amount of deformation areas, differentiating from the control group. Comparing with the control group, the levels of ß-catenin signaled in the lingual bone of the middle third of the alveolar bone were raised in the periods of 5 and 14 days. The increased ß-catenin positive staining intensity was concentrated on osteocytes and gaps of osteocytes. The findings of the present study were in accordance with our hypothesis that the condition of dental extraction can cause the expression of ß-catenin and alter the regimes of bone deformation.

Craniofacial injuries by firearms projectiles: An analysis of 868 deaths in the five regions of Brazil.

Firearms injuries have a legal and medico-legal importance, and are especially lethal when they reach the craniofacial regions of the victim. The present study aims to identify the characteristics of craniofacial lesions resulting from firearm projectiles, to register the most affected craniofacial regions by this type of injury and to verify the demographic profile of the victims. A retrospective study was carried out on the autopsy records produced in the first semester of 2015, in five Institutes of Legal Medicine in Porto Velho, situated in the cities of João Pessoa, Vitória, Porto Alegre and Brasília. Data extracted included sex, skin color and age of the victim, craniofacial region reached, shooting distance, shape and size of the injuries and manner of death (homicide, suicide or accident). Based on the 868 reports analyzed, it was possible to observe 1700 entrance lesions of firearm projectiles in craniofacial regions. Among cases of known manner of death, homicides were the most frequent (97.0%). It was observed a higher frequency of male victims (93.3%), mixed race (62.0%), between the ages of 12 and 29 years (59.4%). In all cases considered as suicide or accident there was only one entrance wound, but in 82.8% of the homicides there were multiple gunshot wounds. The craniofacial most affected regions were temporal (25.2%) and occipital (19.8%). The most common sites of projectiles exit were the temporal (25.3%) and parietal (16.1%). All cases of suicide were related to contact shot (69.2%) or close-range shot (30.8%), and among the homicides the distant range shots were more frequent (54.0%). The shape of entrance wounds was mostly circular (56.8%) and oval (31.3%), and among the exit injuries, the lesions were irregular (43.3%) and starry (24.1%). The entrance wounds showed smaller sizes than the exit lesions (p < 0.0001). The data obtained are useful for guiding research that takes into account craniofacial trauma caused by firearm projectiles, makes it possible to compare this data with those of other countries and can base investigative conclusions based on the analyzes discussed in the present work.

The glossopharyngeal nerve (IX cranial nerve pair): anatomical considerations and neuralgia: literature review / O nervo glossofaringeo (IX par de nervo craniano): considerações anatômicas e neuralgia: revisão da literatura

The glossopharyngeal nerve (IX cranial nerve) is a mixed nerve, with both motor and sensory function. This relates to the tongue and pharynx. Glossopharyngeal neuralgia is a rare nervous neuropathy, with poristic, lancinating and paritary crises, usually unilateral. The aim of the study was to review the literature on glossopharyngeal neuralgia of the nerve (IX cranial nerve), highlighting the anatomical aspects of this nerve and the possible causes and complications of neuralgia as well as forms of treatment. A literature review was carried out in the international Pubmed database. The literature review included 72 articles from 2015 to 2021. The keywords used were: "anatomy of glossopharyngeal neuralgia". Of the 72 articles, 7 were used for this literature review. Uncommon as nervous/glossophingeal etiologies and pathologies are neurological abnormalities/neurovarises and pathologies are neurovascular/neurovariseal lesions. Pharmacological treatment approaches mentioned in the literature were therapy with antiepileptics and antidepressants such as carbamazepine and gabapentin; a microvascular decompression; and gamma knife radiosurgery(AU)

O nervo glossofaríngeo (IX par de nervo craniano) é um nervo misto, contendo função tanto motora como sensitiva. Este nervo relaciona-se com a língua e com a faringe. A neuralgia do nervo glossofaríngeo é uma neurapatia rara, sendo caracterizada por crises dolorosas, lancinantes e paroxísticas, geralmente unilaterais. O objetivo do estudo foi realizar uma revisão de literatura sobre a neuralgia do nervo glossofaríngeo (IX par de nervo craniano), destacando os aspectos anatômicos deste nervo e as possíveis causas e complicações da neuralgia bem como formas de tratamento. Foi realizada uma revisão da literatura na base de dados internacional Pubmed. A revisão da literatura incluiu 72 artigos no período de 2015 a 2021. As palavras-chave utilizadas foram: "anatomia da neuralgia do glossofaríngeo". Dos 72 artigos, 7 foram utilizados para esta revisão de literatura. Verificouse que a neuralgia do nervo glossofaríngeo é incomum e as etiologias mais encontradas foram compressão neurovascular/variações vasculares, patologias e traumas. As abordagens dos tratamentos mencionadas na literatura foram a terapia farmacológica da área com antiepilépticos e antidepressivos, como carbamazepina e gabapentina; a descompressão microvascular; e radiocirurgia com faca gama(AU)

Application and validation of Diagnose Sexuelle Probabiliste V2 tool in a miscegenated population.

The hip bone (os coxae) is the skeletal element that presents the greatest level of sexual dimorphism. Therefore, methods involving the analysis of the os coxae provide the most accurate sex estimation, and DSP2 (Diagnose Sexuelle Probabiliste v.2) is one of the most accurate tools used in this identification. The goal of this study is to apply and validate DSP2 in the identification of 103 os coxae (53 male and 50 female) belonging to a Brazilian-identified skeletal collection. Differences between sexes were statistically significant for all measurements, except for the acetabulo-symphyseal and spino-auricular lengths. From the 103 os coxae analyzed, there was a 9.43% error in male individuals and a 14% error in females. The results revealed that DSP2 can be applied to Brazilian-mixed populations with a good index of accuracy, although at a lower accuracy than other population samples. This study also clearly demonstrates that metric variation of the os coxae is extremely useful in sex estimation and reinforces the notion that pelvic sexual dimorphism is not population-specific.

Alveolar bone healing in rats: micro-CT, immunohistochemical and molecular analysis.

INTRODUCTION: Alveolar bone healing after upper incisor extraction in rats is a classical model of preclinical studies. The underlying morphometric, cellular and molecular mechanism, however, remains imprecise in a unique study. OBJECTIVES: The aim of this study was therefore to characterize the alveolar bone healing after upper incisor extraction in rats by micro computed tomographic (Micro-CT), immunohistochemical and real-time polymerase chain reaction (RT-PCR) analysis. MATERIAL AND METHODS: Thirty animals (Rattus norvegicus, Albinus Wistar) were divided into three groups after upper incisors extraction at 7, 14, and 28 days. Micro-CT was evaluated based on the morphometric parameters. Subsequently, the histological analyses and immunostaining of osteoprotegerin (OPG), receptor activator of nuclear kappa B ligand (RANKL) and tartrate resistant acid phosphate (TRAP) was performed. In addition, RT-PCR analyses of OPG, RANKL, the runt-related transcription factor 2 (RUNX2), osteocalcin (OC), osteopontin (OPN), osterix (OST) and receptor activator of nuclear kappa B (RANK) were performed to determine the expression of these proteins in the alveolar bone healing. RESULTS: Micro-CT: The morphometric parameters of bone volume and trabecular thickness progressively increased over time. Consequently, a gradual decrease in trabecular separation, trabecular space and total bone porosity was observed. Immunohistochemical: There were no differences statistically significant between the positive labeling for OPG, RANKL and TRAP in the different periods. RT-PCR: At 28 days, there was a significant increase in OPG expression, while RANKL expression and the RANKL/OPG ratio both decreased over time. CONCLUSION: Micro-CT showed the newly formed bone had favorable morphometric characteristics of quality and quantity. Beyond the RUNX2, OC, OPN, OST, and RANK proteins expressed in the alveolar bone healing, OPG and RANKL activity showed to be essential for activation of basic multicellular units during the alveolar bone healing.

Daily melatonin administration improves osseointegration in pinealectomized rats.

INTRODUCTION: The hypothesis of this study was that the peri-implant bone healing of the group of pinealectomized rats would differ from the control group. The samples were subjected to immunohistochemical, microtomographic (total porosity and connectivity density), and fluorochrome (mineralized surface) analyses. OBJECTIVES: The goal of this study was to investigate the cellular changes and bone remodeling dynamics along the bone/implant interface in pinealectomized rats. MATERIAL AND METHODS: The total of 18 adult male rats (Rattus norvegicus albinus, Wistar) was divided into three groups (n=6): control (CO), pinealectomized without melatonin (PNX) and pinealectomized with melatonin (PNXm). All animals were submitted to the first surgery (pinealectomy), except the CO group. Thirty days after the pinealectomy without melatonin, the second surgery was conducted, in which all animals received an implant in each tibia (36 titanium implants with surface treatment were installed - Implalife® São Paulo, SP, Brazil). By gavage, the rats of the PNX group received the vehicle solution, and the procedure. RESULTS: Immunohistochemical analysis for runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OP) and osteocalcin (OC) showed that the bone repair process in the PNXm group was similar to that of the CO group, whereas the PNX group showed a delay. The microtomographic parameters of total porosity [Po(tot)] and bone surface (BS) showed no statistically significant differences, whereas for the connective density (Conn.Dn) a statistical difference was found between the CO and PNXm groups. Fluorochrome analysis of the active mineralized surface showed statistically significant difference between the CO and PNX and between the CO and PNXm groups. CONCLUSION: The absence of the pineal gland impaired the bone repair process during osseointegration, however the daily melatonin replacement was able to restore this response.

A SERM increasing the expression of the osteoblastogenesis and mineralization-related proteins and improving quality of bone tissue in an experimental model of osteoporosis.

Raloxifene is an antiresorptive drug, selective estrogen receptor modulator (SERM) used in the treatment of osteoporosis. Objective To evaluate proteins related to bone repair at the peri-implant bone in a rat model of osteoporosis treated with raloxifene. Material and Methods 72 rats were divided into three groups: SHAM (healthy animals), OVX (ovariectomized animals), and RLX (ovariectomized animals treated with raloxifene). Raloxifene was administered by gavage (1 mg/kg/day). Tibial implantation was performed 30 days after ovariectomy, and animals were euthanized at 14, 42, and 60 days postoperatively. Samples were collected and analyzed by immunohistochemical reactions, molecular analysis, and microtomographic parameters. Results RLX showed intense staining of all investigated proteins at both time points except for RUNX2. These results were similar to SHAM and opposite to OVX, showing mild staining. The PCR gene expression of OC and ALP values for RLX (P<0.05) followed by SHAM and OVX groups. For BSP data, the highest expression was observed in the RLX groups and the lowest expression was observed in the OVX groups (P<0.05). For RUNX2 data, RLX and SHAM groups showed greater values compared to OVX (P<0.05). At 60 days postoperatively, microtomography parameters, related to closed porosity, showed higher values for (Po.N), (Po.V), and (Po) in RLX and SHAM groups, whereas OVX groups showed lower results (P<0.05); (BV) values (P=0.009); regarding total porosity (Po.tot), RLX group had statistically significant lower values than OVX and SHAM groups (P=0.009). Regarding the open porosity (Po.V and Po), the SHAM group presented the highest values, followed by OVX and RLX groups (P<0.05). The Structural Model Index (SMI), RLX group showed a value closer to zero than SHAM group (P<0.05). Conclusions Raloxifene had a positive effect on the expression of osteoblastogenesis/mineralization-related proteins and on micro-CT parameters related to peri-implant bone healing.

Computational Approach to Identify Different Injuries by Firearms.

Complications arise in the analysis of gunshot wounds to the maxillofacial region, when neither the projectile nor the gun is found at the crime scene. We simulated 5- and 15-cm firing distances at a human mandible to investigate the external morphology of entrance wounds based on fire range. The ammunition models, .40-caliber S&W, .380-caliber, and 9 × 19-mm Luger, were constructed with free-form NURBS surfaces. In a dynamic simulation, projectiles were fired against mandibular body 3D model at 5 and 15 cm. All entrance wounds presented oval aspect. Maximum diameter and von Mises stress values were 16.5 mm and 50.8 MPa, both for .40-caliber S&W fired at 5 cm. The maximum energy loss was 138.4 J for .40 S&W fired at 15 cm. In conclusion, the mandible was most affected by .40-caliber S&W and morphological differences were observable in holes caused by different incoming projectile calibers fired at different distances.

The effect of a hydroxyapatite impregnated PCL membrane in rat subcritical calvarial bone defects.

OBJECTIVE: The present study evaluated the effect of polymeric-nanofibers membranes impregnated with microparticulate hydroxyapatite (HA) in the subcritical calvarial bone defects (SCBD) healing. DESIGN: PCL membranes with and without HA were obtained by electrospinning. SCBD were perforated (3.3mm) in left and right sides of 36 rat calvarias. The right-side SBCD of 18 animals was filled with HA mixed with blood clot and blood clot at the contralateral side. The remaining animals received PCL+HA membrane at the right-side SCBD and PCL membrane at the contralateral side. Animals were killed after 30, 60 and 90days after surgery. Bone defect volume (in mm3) was measured by tomography (CBCT). Qualitative histological analysis and SBCD area (in mm2) were measured. Quantitative data were submitted to Kruskal-Wallis/Dunn tests. RESULTS: Reduction of SBCD volume was observed in all treatments but PCL. Association with HA significantly improved bone healing induced by PCL and blood clot. PCL+HA induced the lowest SBCD volume at 60 and 90days. Complete bone healing was not observed even at 90days in SCBD treated with blood clot. In every period, more bone formation was observed for SCBD treated with membranes. CONCLUSIONS: We concluded that both PCL membrane and HA were able to improve bone healing.

Association between Facial Type and Mandibular Canal Morphology - Analysis in Digital Panoramic Radiographs.

In this study we investigate the association between facial type and mandibular canal course morphology analysing this in digital panoramic radiographs images. We used 603 digital images from panoramic radiographs. We selected only panoramic radiographs of fully dentate individuals, who had all lower molars bilaterally and with complete root formation. The sample distribution was determined by facial type and sex. The course of the mandibular canal, as seen in the panoramic radiographs, was classified into 3 types, bilaterally. The classification used was: type 1 if the mandibular canal is in contact or is positioned at most 2 mm from the root apex of the three permanent molars; type 2 if the mandibular canal is located halfway between the root apex of the three permanent molars and a half away from the mandibular basis; and type 3 if the mandibular canal is in contact with or approaches, a maximum of 2 mm from the cortical bone of the mandibular basis. For results, the data were analyzed by Chi-square test (p<0.05). Data analysis (Chi-square) showed there were more canals type 2 (p=0.0012) and fewer canals type 1 (p=0.0336) in females than in males, without association with the facial types. In conclusion, the facial type does not associated with the mandibular canal course analyzed.