Ultraviolet C as a method of disinfecting medical silicone used in facial prostheses: An in vitro study - Part 2.

STATEMENT OF PROBLEM: Disinfection is an important factor in preserving facial prostheses and maintaining tissue health. However, whether disinfection with ultraviolet C is an effective disinfection method is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effectiveness of irradiation with different exposure durations of an ultraviolet-C light-emitting diode in the disinfection of the silicone (A-588-1; Factor II) used in facial prostheses. MATERIAL AND METHODS: A total of 216 specimens were prepared, contaminated by multispecies biofilm, and divided into 9 groups (n=24) for different treatments: chlorhexidine 0.12% (G CHG), ultraviolet-C light-emitting diode for 5 minutes (G UVC5), ultraviolet-C light-emitting diode for 10 minutes (G UVC10), ultraviolet-C light-emitting diode for 20 minutes (G UVC20), their respective untreated controls (Gcontrol CHG, Gcontrol UVC5, Gcontrol UVC10, Gcontrol UVC20), and dimethyl sulfoxide (G DMSO) as the negative control. Cell viability was measured by using the methyl tetrazolium salt (MTT) method. Two statistical analyses were performed. First, a 2×3 ANOVA was carried out to compare the control groups (Gcontrol UVC5, Gcontrol UVC10, and Gcontrol UVC20) and the experimental groups of UV-C LED light with different exposure durations (G UVC5, G UVC10, and G UVC20). The second analysis was performed using generalized linear models to compare the optical density of the groups (G UVC5, G UVC10, G UVC20, G CHG, and G DMSO). RESULTS: Cell viability results demonstrated a microbial reduction after exposure to the ultraviolet-C light-emitting diode for 20 minutes (G UVC20) compared with untreated controls (P<.05). The 5- and 10-minute exposures were statistically similar to their respective control groups (P>.05). The 20 minutes exposure had the lowest average optical density value, being statistically different from the 5-minute exposure (P<.05). A 20-minute exposure to the ultraviolet-C light-emitting diode (G UVC20) was similarly effective when compared with the standard disinfection treatment (G CHG) and dimethyl sulfoxide (G DMSO) (P>.05). CONCLUSIONS: Irradiation with an ultraviolet-C light-emitting diode for 20 minutes decreased the in vitro microbial cell viability on the medical silicone used in facial prostheses.

Influence of Restorative Material on the Distribution of Loads to the Bone in Hybrid Abutment Crowns-In Vitro Study.

Background: The objective of this study was to evaluate the load transmitted to the peri-implant bone by seven different restorative materials in single-unit rehabilitations with morse taper implants using a strain gauge. Materials: In a polyurethane block that simulated type III bone, a morse taper platform implant was installed (3.5 × 11 mm) in the center and 1 mm below the test base surface, and four strain gauges were installed around the implant, simulating the mesial, distal, buccal and lingual positions. Seven similar hybrid abutment crowns were crafted to simulate a lower premolar using different materials: 1-PMMA; 2-glass ceramic over resin matrix; 3-PEEK + lithium disilicate; 4-metal-ceramic; 5-lithium disilicate; 6-zirconia + feldspathic; 7-monolithic zirconia. All groups underwent axial and oblique loads (45 degrees) of 150 N from a universal testing machine. Five measurements (n = 5) were performed with each material and for each load type; the microdeformation data underwent statistical analysis. The data were obtained in microdeformation (µÎµ), and the significance level was set at p ≤ 0.05. Results: There was no statistically significant difference in the evaluation among the materials under either the axial load or the oblique load at 45 degrees. In turn, in the comparison between axial load and oblique load, there was a difference in load for all materials. Conclusion: The restorative material did not influence the load transmitted to the bone. Furthermore, the load transmitted to the bone was greater when it occurred obliquely at 45° regardless of the material used. In conclusion, it appeared that the different elastic modulus of each material did not influence the load transmission to the peri-implant bone.

3D Bitemark Analysis in Forensic Odontology Utilizing a Smartphone Camera and Open-Source Monoscopic Photogrammetry Surface Scanning

Abstract Bitemark analysis is a challenging procedure in the field of criminal case investigation. The unique characteristics of dentition are used to find the best match between the existing patterned injury and the suspected perpetrator in bitemark identification. Bitemark analysis accuracy can be influenced by various factors, including biting pressure, tooth morphology, skin elasticity, dental cast duplication, timing, and image quality. This review article discusses the potential of a smartphone camera as an alternative method for 3D bitemark analysis. Bitemark evidence on human skin and food should be immediately recorded or duplicated to retrieve long-lasting proof, allowing for a sufficient examination period. Various studies utilizing two-dimensional (2D) and three-dimensional (3D) technologies have been developed to obtain an adequate bitemark analysis. 3D imaging technology provides accurate and precise analysis. However, the currently available method using an intraoral scanner (IOS) requires high-cost specialized equipment and a well-trained operator. The numerous advantages of monoscopic photogrammetry may lead to a novel method of 3D bitemark analysis in forensic odontology. Smartphone cameras and monoscopic photogrammetry methodology could lead to a novel method of 3D bitemark analysis with an efficient cost and readily available equipment.

Oculofacial Prosthetic Rehabilitation Complemented With Temporary Fillers and Neurotoxin.

ABSTRACT: Surgical treatment of head and neck cancer causes severe tissue loss, therefore, deformities and psychosocial consequences. In cases involving orbit exenteration, satisfactory reconstruction can only be achieved with prosthetic replacement, despite successful reconstructive plastic surgery. Extraoral implants, 3D scanning, and prototyping technologies have contributed to increase satisfactory aesthetic results of oculofacial prosthesis. However, to achieve prosthetic rehabilitation refinement, patients' biological tissues have been treated with injectable cosmetic adjuncts methods as complements to results. This study aimed to describe the use of botulinum toxin type A, hyaluronic acid, and calcium hydroxyapatite previously to oculofacial prostheses manufacturing, in 5 oncologic patients of a rehabilitation unit. Outcomes produced by additional cosmetic methods on tissues, prostheses planning, and overall facial rehabilitation were observed and registered by photographs. Botulinum toxin type A, hyaluronic acid, and calcium hydroxyapatite has shown to be useful in improving asymmetries, volumizing surgical depressions and dissembling atrophic scars. Presenting an additional resource to improve overall results, enabling the manufacturing of smaller, thinner, and better-fitting oculofacial prostheses. Limitations as chronic infection and necrosis episodes, related to filler injection into previously irradiated sites, were described. The temporary effect of the materials used generates a need for reapplications but increases the safety of such procedures and enables patients' cancer treatment follow-up.

Ultraviolet C as a method of disinfecting medical silicone used in facial prostheses: An in vitro study.

STATEMENT OF PROBLEM: Hygiene and disinfection are important factors for preserving facial prostheses and supporting tissue health. However, a method that does not accelerate degradation or color change is necessary. PURPOSE: The purpose of this in vitro study was to evaluate the effectiveness of irradiation with ultraviolet C light-emitting diode (UV-C LED) light in the disinfection and initial color stability of the silicone (A-588-1; Factor II) used in facial prostheses. MATERIAL AND METHODS: One hundred and twenty specimens were made, contaminated by multispecies biofilm, and divided into 5 groups (n=24) with different treatments: control, distilled water, 0.12% chlorhexidine, UV-C LED light, and dimethyl sulfoxide (DMSO) as the negative control. Cell viability was measured by the methyl tetrazolium salt method. Statistical analysis was performed by generalized linear models. Additional descriptive analysis was performed for color analysis by using 16 silicone specimens made with light and dark intrinsic coloring in 4 groups (controls and treatments n=4) submitted to UV-C LED light. The ΔE of the specimens was obtained by CIEDE200. RESULTS: The results of cell viability demonstrated a statistically significant difference among the groups (P<.001), with a microbial reduction after UVC-LED exposure compared with the control group. Regarding the color, the groups presented an average ΔE (light 0.205 and dark 0.308) compatible with visually imperceptible changes (light <0.7 and dark <1.2). CONCLUSIONS: Irradiation with UV-C LED light decreased the in vitro microbial cell viability of the medical silicone used in facial prostheses, demonstrating initial color stability.

A Digital Method to Fabricate the Ocular Portion of An Orbital Prosthesis with A Smartphone Camera, Color Calibration and Digital Printing.

Conventional techniques described in the literature for the manufacture of ocular prostheses are time-consuming since they involve manual work. The use of technologies could improve this laborious process, providing better esthetic outcomes. This technique describes how to manufacture the ocular portion of an orbital prosthesis using a smartphone camera, color calibration with a tooth shade guide, and digital printing. This method allows clinicians to fabricate customized ocular prosthesis by using a photograph of the patient's eye, thus eliminating the need for hand-painting and manual work, and reducing fabrication time.

In Vitro Analysis of the Implant-Abutment Interface Connection and Bacterial Infiltration in Two Extraoral Implant Models.

PURPOSE: To compare the connection microgaps and the bacterial infiltration of implant-abutment interfaces of two extraoral implant models. MATERIALS AND METHODS: Two implant models were used: the inner connection and the flush connection types. The implant-abutment microgaps of five sets of each extraoral implant were evaluated with scanning electron microscopy. Eleven additional sets of each model design were immersed in Staphylococcus aureus cultures for 24 hours, and samples were obtained from the external surface and from the implant's internal chamber to quantify the colony-forming units. RESULTS: Scanning electron microscopy analysis showed that microgaps of the flush connection were smaller compared with the inner connection (P < .0001), and that bacterial counts were higher at the inner connection compared with the flush connection (P < .0001). CONCLUSION: Within the limitations of this experimental study, it can be concluded that the flush connection model presented a smaller microgap and fewer bacterial colonies compared with the inner connection model.

Quality of life assessment of patients utilizing orbital implant-supported prostheses.

STATEMENT OF PROBLEM: Evaluate the effect of orbital prosthesis retained by implants through a specific quality of life (QOL) questionnaire provides important information on patients QOL, great incentive for the multidisciplinary team and public health support to continue work in this area. PURPOSE: The objective of the study was to evaluate patient satisfaction with orbital implant-supported prostheses using an adapted quality of life questionnaire. MATERIALS AND METHODS: Forty five patients using orbital implant-supported prostheses for a period ranging from six to 120 months. The subjects answered a questionnaire that consisted of 10 questions covering appearance, retention, conspicuousness, self-confidence, difficulty of placement, difficulty of removal, cleaning, limitation of activities, discomfort of tissues, and recommendation of the method to other patients. Answers were expressed using a visual 100-mm scale. The arithmetic mean of the responses was converted into a percentage to represent the satisfaction index. RESULTS: Patients demonstrated a high level of satisfaction on all items, with the lowest rate being for aesthetics and the highest being for recommending the method to other patients. High satisfaction rates regarding the placement and removal of the prosthesis, discomfort to the tissues, and cleaning suggest the ease of handling of the prosthesis. High satisfaction with retention, self-confidence, conspicuousness of the prosthesis, and limitation of activities indicated an association with a better social life. CONCLUSIONS: The results showed that use of bone anchorage technique of extraoral prostheses provided a high level of satisfaction among patients, confirming that osseointegrated implants are a very important resource for the rehabilitation of orbital deformities.

Estudo de comparação por extensometria entre dois modelos de implante: extraoral e intraoral (estudo piloto) / Comparison study for extensometry between two implant models: extra-oral and intraoral (pilot study)

Objetivo: avaliar, por meio de extensometria, a infl uência da flange do implante de titânio na deformação superficial do osso. Material e métodos: um bloco de poliuretano simulando um osso tipo I mais corticalizado e menos medular (40 PCF) recebeu um implante de hexágono externo intraoral, sem flange 3,75 mm x 8,5 mm (G1) e um implante de hexágono externo extraoral, com flange 3,75 mm x 8 mm (G2). Em seguida, foram instalados componentes standard com 2 mm de altura de cinta metálica e cilindros metálicos para restauração provisória. Dois extensômetros lineares foram colados na superfície do bloco (mesial e distal de cada implante), e uma carga axial de 100 Ncm em uma máquina de ensaio universal foi aplicada, com cinco medições de microdeformação (µÎµ) para cada implante. Os dados foram submetidos ao teste Shapiro-Wilk para verifi car a homogenidade dos dados e em seguida ao teste t Student. Resultados: as médias e desvios-padrão obtidos foram: G1: 148,2 ± 5,84 e G2: 92,4 ± 11,24 µÆ, com diferença estatística significativa entre os grupos. Conclusão: os implantes extraorais tiveram melhor comportamento mecânico para as cargas axiais do que os implantes intraorais, sendo que a flange melhorou a distribuição da carga na superfície do bloco de poliuretano.

Objectives: to evaluate, by means of extensometry, the influence of the titanium implant flange on the superficial deformation of the bone. Material and methods: a polyurethane block simulating a more corticalized and less spinal type I bone (40 PCF) received an external intraoral hexagon implant with a 3.75 mm x 8.5 mm fl ange (G1) and an extraoral external hexagon implant, with flange 3.75 mm x 8 mm (G2). Subsequently, standard components with 2 mm high of metal strap and metal cylinders were installed for temporary restoration. Two linear strain gauges were glued to the surface of the block (mesial and distal of each implant), and an axial load of 100N in a universal test machine was applied with five microdemorphometric measurements (µÎµ) for each implant. The data were submitted to the Shapiro-Wilks test to verify the homogeneity of the data and then to the t-student test. Results: the means and standard deviations obtained were: G1: 148.2 ± 5.84 and G2: 92.4 ± 11.24 µÎµ, with signifi cant statistical difference between the groups. Conclusion: extraoral implants had better mechanical behavior for axial loads than intraoral implants, and the flange improved the load distribution on the surface of the polyurethane block.

Extraoral Implants for Anchoring Facial Prostheses: Evaluation of Success and Survival Rates in Three Anatomical Regions.

PURPOSE: The aim of this study was to evaluate the success and survival rates of extraoral implants for the fixation of facial prostheses in three anatomical regions. MATERIALS AND METHODS: Subjects were consecutive patients with facial defects who underwent implant placement by the same surgeon in the orbital, nasal, and auricular regions between 2003 and 2012. After a minimum of 4 months of osseointegration, prostheses were anchored to the implants, and the patients were monitored for 11 to 111 months. Success rate, implant survival time, and occurrence of previous radiotherapy were evaluated. Rate of implant survival was estimated as a function of the anatomical region of the three groups (orbital, nasal, or auricular), and confidence intervals were calculated using Kaplan-Meier analysis with α = .05. RESULTS: In the 68 patients' 138 fixed implants, 48 showed defects in the orbital, 9 in the nasal, and 11 in the auricular region. The success rates and survival times were 95.9% and 8.6 years for the orbital, 92.9% and 2.8 years for the nasal, and 92% and 9.0 years for the auricular region, respectively. The success rate of implants in previously irradiated regions was 90.3% for the orbital and 100% for the auricular region. None of the patients was irradiated in the nasal region. CONCLUSION: No significant differences in implant success or survival were observed with regard to anatomical region or previous irradiation.

Monoscopic photogrammetry to obtain 3D models by a mobile device: a method for making facial prostheses.

PURPOSE: The aim of this study is to present the development of a new technique to obtain 3D models using photogrammetry by a mobile device and free software, as a method for making digital facial impressions of patients with maxillofacial defects for the final purpose of 3D printing of facial prostheses. METHODS: With the use of a mobile device, free software and a photo capture protocol, 2D captures of the anatomy of a patient with a facial defect were transformed into a 3D model. The resultant digital models were evaluated for visual and technical integrity. The technical process and resultant models were described and analyzed for technical and clinical usability. RESULTS: Generating 3D models to make digital face impressions was possible by the use of photogrammetry with photos taken by a mobile device. The facial anatomy of the patient was reproduced by a *.3dp and a *.stl file with no major irregularities. 3D printing was possible. CONCLUSIONS: An alternative method for capturing facial anatomy is possible using a mobile device for the purpose of obtaining and designing 3D models for facial rehabilitation. Further studies must be realized to compare 3D modeling among different techniques and systems. CLINICAL IMPLICATION: Free software and low cost equipment could be a feasible solution to obtain 3D models for making digital face impressions for maxillofacial prostheses, improving access for clinical centers that do not have high cost technology considered as a prior acquisition.

Influence of implant-retained silicone oculo-palpebral prosthesis on stress distribution: a pilot study using a photoelastic model.

PURPOSE: The purpose of this pilot study was to evaluate the behavior of stresses surrounding orbital model implants subjected to a load of a silicone oculo-palpebral prosthesis. MATERIALS AND METHODS: A photoelastic model was constructed mimicking the orbital cavity of an adult patient who underwent left orbital resection. Two 3.75 × 5-mm extraoral implants with 3.75 × 5.25-mm magnetic connectors were placed in the model to anchor a silicone oculo-palpebral prosthesis. The stress generated by prosthesis retention was evaluated using photoelasticity at 15, 30, and 60 minutes. The polariscope images were analyzed qualitatively at five areas surrounding the implants. These same areas were analyzed quantitatively using Matlab software based on the RGB color pattern. Data were compared with the Wilcoxon test. RESULTS: Using fringe localization, the qualitative analysis demonstrated that the area between the implants had the greatest stress. The quantitative analysis showed that the peri-implant stress increased significantly in proportion to the increase in prosthesis retention time. CONCLUSION: The oculo-palpebral prosthesis generated stress around the implants, and the stress intensity was directly proportional to the duration of use.

Surgical treatment of bisphosphonate-related osteonecrosis of the jaws with the use of buccal fat pad: case report.

Bisphosphonate-related osteonecrosis of the jaws (BROJ) has been described since 2003 as an adverse effect of bisphosphonate medications. These drugs act on the vasculature and bone remodeling, mainly on osteoclastic activity and can cause areas of necrotic bone exposure. Treatment for the BROJ is not yet defined, but surgical treatment is one of the forms proposed, which may cause oral deformities like sinus communication in some cases. In situations like this the buccal fat pad is an important alternative for coating nasal-oral communications, due its large blood supply, elasticity, absence of restriction by age and safety. This paper presents the case of a 58-year-old woman with BROJ in the left maxilla caused by the use of zoledronic acid for metastatic breast cancer. The extensive necrotic bone area was surgically removed resulting in oral sinus communication. A buccal fat pad was used to cover the defect. More studies should be performed regarding the treatment of BROJ but, if necessary, a buccal fat pad flap could be an alternative to solve nasal-oral communications related to BROJ.

Surgical Treatment of Bisphosphonate-Related Osteonecrosis of the Jaws with the Use of Buccal Fat Pad: Case Report

Bisphosphonate-related osteonecrosis of the jaws (BROJ) has been described since 2003 as an adverse effect of bisphosphonate medications. These drugs act on the vasculature and bone remodeling, mainly on osteoclastic activity and can cause areas of necrotic bone exposure. Treatment for the BROJ is not yet defined, but surgical treatment is one of the forms proposed, which may cause oral deformities like sinus communication in some cases. In situations like this the buccal fat pad is an important alternative for coating nasal-oral communications, due its large blood supply, elasticity, absence of restriction by age and safety. This paper presents the case of a 58-year-old woman with BROJ in the left maxilla caused by the use of zoledronic acid for metastatic breast cancer. The extensive necrotic bone area was surgically removed resulting in oral sinus communication. A buccal fat pad was used to cover the defect. More studies should be performed regarding the treatment of BROJ but, if necessary, a buccal fat pad flap could be an alternative to solve nasal-oral communications related to BROJ.

Osteonecrose dos maxilares por bifosfonatos (OMB) tem sido descrita desde 2003 como um efeito adverso dos medicamentos bifosfonatos. Essas drogas atuam sobre a vascularização e remodelação óssea, principalmente na atividade osteoclástica, podendo gerar áreas de exposição óssea necrótica. O tratamento para a doença ainda não é definido, mas o tratamento cirúrgico é uma das formas preconizadas que, em algumas situações podem ocasionar deformações orais como as comunicações buco-sinusais. Em situações como esta o tecido adiposo bucal é uma alternativa importante para o recobrimento da comunicação oro-nasal, devido ao seu grande suprimento sanguíneo, elasticidade, ausência de restrição pela idade e segurança. Este trabalho apresenta um caso clínico de paciente de 58 anos do sexo feminino, portadora de OMB em maxila esquerda pelo uso de ácido zoledrônico para câncer metastático. A extensa remoção da porção óssea necrótica resultou em fístula buco-sinusal. O retalho do tecido adiposo bucal foi utilizado para cobrir o defeito. Mais estudos devem ser realizados com relação ao tratamento de OMB, no entanto, se necessário, o retalho de tecido adiposo bucal poderia ser uma alternativa para resolver a comunicação oro-nasal relacionada à OMB.

Orbit rehabilitation with extraoral implants: impact of radiotherapy.

PURPOSE: The aim of the study was to compare the success rates of osseointegration among irradiated and nonirradiated cases submitted to implant placement for anchorage of orbit prostheses from 2003 to 2011. MATERIALS AND METHODS: Charts of 45 consecutive patients were analyzed, 31 men and 14 women, and they were divided in two groups, considering previous irradiation therapy. Nonirradiated group had 33 patients, and irradiated group had 12 patients. In total, 138 implants were installed, 42 (30.4%) in previously irradiated bone. RESULTS: The overall implant survival rate was 96.4% with a success rate of 99.0% among the nonirradiated patients and 90.5% among the irradiated patients (p = 0.03). CONCLUSIONS: Results showed that irradiated sites had a worse prognosis related to success of osseointegration, although the 90.5% survival rate in this group indicates that implant placement is a feasible alternative to anchor orbit prostheses considering the benefits that this technique offers to patients.

Assessment of the correlation between insertion torque and resonance frequency analysis of implants placed in bone tissue of different densities.

The primary stability of dental implants is fundamental for osseointegration. Therefore, this study aimed to assess the correlation between insertion torque (IT) and resonance frequency analysis (RFA) of implants placed in mandibles and maxillas of different bone densities. Eighty dental implants were placed in maxillas and mandibles, and IT and the implant stability quotient (ISQ) were measured at the time of implant insertion. Bone density was assessed subjectively by the Lekholm and Zarb index. The type I and II densities were grouped together (group A)as were the type III and IV densities (group B). The IT in group A was higher (Student t test, P = .0013) than in group B (46.27 ± 18.51 Ncm, 33.62 ± 14.74 Ncm, respectively). The implants placed in group A showed higher ISQ (Student t test, P = .0004) than those placed in group B (70.09 ± 7.50, 63.66 ± 8.00, respectively). A significant correlation between IT and the ISQ value was observed for group A (Pearson correlation test; r = 0.35; P = .0213) and for group B (r = 0.37; P = .0224). Within the limitations of this study, it was possible to conclude that there is a correlation between IT and RFA of implants placed in mandibles and maxillas of different bone densities.

Photoelastic stress analysis surrounding different implant designs under simulated static loading.

OBJECTIVE: The proposal of this study was to use a photoelasticity method to analyze the stress dissipation in the bone surrounding an implant under simulated loading. MATERIALS AND METHODS: Four implant systems with different internal connection designs were studied: conical connection (group 1), triangular connection (group 2), Morse taper (group 3), and internal hexagon (group 4). After the models' inclusion in a photoelastic resin, they were subjected to static loads of 100, 150, and 200 N. The lengths of fringes that were generated were measured at the bone crest parallel to the neck of the implant and along the implant body, as well as the dissipation of force across the entire area of extension. RESULTS: Lower stress was observed at the crestal bone in groups 1 and 3 with no significant increase (P < 0.05) in different levels of load, whereas the stress levels in groups 2 and 4 were observed to be higher with loads of all intensities with significant differences from the other groups (P < 0.05). CONCLUSIONS: The type of connection and the implant neck design influenced the dissipation of force. The conical-type connection exhibited better load dissipation in the neck area, regardless of the load applied on the implant.

Bisphosphonate-related osteonecrosis of the jaws: analysis of a case series at a dental school.

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is an adverse effect of drugs used to treat bone metabolism diseases, such as osteoporosis and bone metastases. The present study retrospectively evaluated the clinical characteristics and evolution of BRONJ cases that were diagnosed and treated at a dental school from 2004 to 2011. During that period, 13 patients met the criteria of the study among a population of 2,342 patients with oral lesions. Of the 13 patients, 12 were females. Ten were intravenous bisphosphonate users, and nine had breast cancer as the primary disease. Eight mandibular cases were observed. Eight patients interrupted the use of the bisphosphonates temporarily during the treatment. Surgical treatment was conducted in 10 patients, which was associated with platelet-rich plasma in six cases, which led to a regression to Stage I in 50% of these and cure in 33.3%. Of the total sample, four (30.8%) cases were cured, six (46.1%) regressed to Stage I, and three (23.1%) remained in Stage II after treatment. Dental rehabilitation occurred in seven patients. Dissemination of knowledge among professionals is essential for prevention and early diagnosis of BRONJ. Dental schools must act as reference centers and participate in the multidisciplinary care of bisphosphonate users.

Avaliação por extensometria da deformação superficial do osso, gerada por próteses sobre implantes com diferentes pilares protéticos em função do cantilever: estudo in vitro / Strain gauge analysis of coronal bone deformation according different prosthetic implant abutment and cantilever length types: an in vitro study

O objetivo deste estudo foi avaliar a transmissão da carga mastigatória ao osso de suporte em próteses implantossuportadas em função do cantiléver, variando o tipo de pilar (Micro-Unite Ucla). A partir de dois modelos de poliuretano (norma ASTM F –1839), foram inseridos três implantes em cada, a uma distância de 8 mm, que conformaram os grupos: 1) implantes de hexágono externo e pilares Micro-Unit; 2) implantes de hexágono externo e pilares Ucla. Foram confeccionadas estruturas protéticas em resina acrílica ativada quimicamente sob cilindros com base de Co-Cr, que foram fundidas pela técnica convencional à brasagem. Foram fixados extensômetros no poliuretano entre os implantes e um na distal do implante mais próximo ao cantiléver. Em uma máquina de ensaio universal (2000RK – Kratos, São Paulo, Brasil), foi realizada a aplicação da carga de 150 N. A carga foi aplicada entre os implantes e no cantiléver nos intervalos de 5, 10, 15, 20 e 25 mm. Os dados obtidos foram analisados estatisticamente para cada extensômetro e levando em consideração a extensão do cantiléver. Quanto maior a extensão do cantiléver, maior a deformação superficial do osso ao redor do implante mais distal. A utilização do componente tipo Micro-Unit apresentou valores de deformação inferiores em relação ao Ucla.

Objectives: to evaluate transmission of masticatory loads according to different prosthetic implant abutment and cantilever lengths. Material and methods: two polyurethane models (ASTM F-1839) received 3 external hex dental implants 8 mm each apart divided into two groups: 1) Micro-Unit and, 2) Ucla. Metallic frameworks were prepared using acrylic resin and cast over CoCr prosthetic cylinders. Strain gauges were attached at the polyurethane-abutment interface and at the distal part of the implant near the cantilever. After, a 150 N load (2000 RK, Kratos, São Paulo, Brazil) was applied at 15, 20, and 25 mm from the most distal implant. Statistical analysis considered abutment type and cantilever lengths. Results: longer cantilevers generate more deformation in the distal implant. Deformation values at Micro-Unit were lower than at Ucla abutment type.

Formação óssea e contato osso-implante após irradiação e colocação do implante dentário: estudo experimental no modelo de tíbia em ratos / Bone formation and bone-implant contact after irradiation and dental implant placement: an experimental study in the rat tibiae model

Objetivo: comparar a formação óssea e o contato entre osso e implante (BIC) em osso irradiado usando um modelo de tíbia em ratos. Material e métodos: seis animais Rattus norvegicus (Wistar, 90 a 120 dias, peso entre 350 a 400 g) receberam 30 Gy de radiação ionizante (distância pele-fonte: 80 cm) na tíbia direita (grupo-experimental). A tíbia esquerda serviu como grupo-controle. Após 30 dias, implantes de titânio (2,5 mm diâmetro, 3 mm-comprimento, superfície tratada) foram colocados em ambos os grupos. Todos os animais foram sacrificados após 56 dias, e as amostras foram analisadas histomorfometricamente para área de formação óssea no espaço entre as roscas e o BIC. Resultados: para a formação óssea, as médias foram 44,91 ± 13,31% (grupo-controle), contra 43,16 ± 28,73% (grupo-experimental) (teste t; p=0,44). Para o contato entre osso e implante, o percentual foi de 39,51 ± 17,22% contra 33,36 ± 26,15%, respectivamente (teste t, p=0,31). Conclusão: dentro dos limites deste estudo, não houve diferença na formação óssea e no contato entre osso e implantes na avaliação histomorfométrica de implantes instalados em tíbias de ratos, submetidas previamente a 30 Gy de radiação ionizante.