Accuracy of dental implants positioning in computer-assisted surgeries: In vitro study.

OBJECTIVES: The aim of this study is to presents an experimental method for surgical guide confection using an intraoral scanner to obtain a 3D model of the patient's complete denture and compare its accuracy with the conventional methodology using computed tomography. STUDY DESIGN: This prospective in-vitro study used 30 polyurethane pre-manufactured mandibles which were divided into two groups, conventional technique (group I) and a new method using intraoral scanner (group II), establishing the virtually planned position of the dental implants as a control group, considered as the gold standard for postoperative comparison. RESULTS: The difference between these methods is close to zero and not statistically significant (p > 0.05), being heigh deviation (Xh) with p:0.130 and angulation difference of dental implants between the groups (Ang) with p:0.396. CONCLUSION: The acquisition of stereolithography image of the prosthesis using an intraoral scanner has a clinically acceptable accuracy, being in agreement with the conventional method.

Odontoma composto em maxila: relato de caso / Compound odontoma in maxilla: a case report / Odontoma compuesto en maxilar: reporte de caso

Introdução: Os odontomas compostos são tumores odontogênicos benignos mistos, mais comumente encontrados na região anterior da maxila, com predileção pela segunda década de vida, podendo levar à má oclusão, interferência na erupção dos dentes, deslocamento e malformação dos dentes adjacentes. Em alguns casos, leva à erupção ectópica, diastemas persistentes, divergências do longo eixo do dente e assimetria facial. Devido a isso, o tratamento mais comum é a remoção cirúrgica conservadora. Relato de caso: Paciente do sexo masculino, 13 anos, com presença de odontoma composto em região anterior de maxila. O mesmo foi submetido à enucleação cirúrgica para remoção e diagnóstico adequado da lesão, a partir da análise anatomopatológica do espécime. Conclusão: Por ser uma patologia comum nos maxilares, é adequado que o profissional conheça suas principais características para o correto diagnóstico, bem como o tratamento mais adequado para cada paciente... (AU)

Introduction: Compound odontomas are mixed benign odontogenic tumors, most commonly found in the anterior maxillary region, with a predilection for the second decade of life, may lead to malocclusion, interference in the eruption of teeth, displacement and malformation of adjacent teeth. In some cases, it leads to ectopic eruption, persistent diastemas, divergences of the long axis of the tooth and facial asymmetry. Because of this, the most common treatment is conservative surgical removal. Case report: A 13 year-old male, with presence of compound odontoma in anterior region of maxilla. The patient was underwent surgical enucleation for treatment and propper diagnosis of lesion. Conclusion: As it is a common pathology in the jaws, it is appropriate for the professional to know its main characteristics for the correct diagnosis, as well as the most appropriate treatment for each patient... (AU)

Introduccíon: Los odontomas compuestos son tumores odontogénicos mixtos benignos, que se encuentran con mayor frecuencia en la región anterior del maxilar, con predilección por la segunda década de la vida, lo que puede ocasionar maloclusión, interferencia con la erupción dentaria, desplazamiento y malformación de los dientes adyacentes. En algunos casos, conduce a erupción ectópica, diastema persistente, divergencia del eje longitudinal del diente y asimetría facial. Debido a esto, el tratamiento más común es la extirpación quirúrgica conservadora. Reporte de caso: Paciente masculino, de 13 años, con presencia de odontoma compuesto en la región anterior del maxilar. El mismo fue sometido a enucleación quirúrgica para extirpación y adecuado diagnóstico de la lesión, a partir del análisis anatomopatológico del espécimen. Conclusíon: Por tratarse de una patología común en los maxilares, es conveniente que el profesional conozca sus principales características para el correcto diagnóstico, así como el tratamiento más adecuado para cada paciente... (AU)

Retrospective analysis of the predictability of using three-dimensional models for preoperative planning of the length of zygomatic implants.

PURPOSE: This present study aimed to retrospectively evaluate the predictability of using three-dimensional models (TDMs) to plan the preoperative lengths of zygomatic implants (ZIs). METHODS: The records of all patients that received such implants between March 2007 and March 2019 were evaluated. The ZI lengths predicted on the TDMs were compared to the lengths of the implants the patients received. RESULTS: In total, the records of 74 patients were evaluated, of which 37 records met the criteria of inclusion, and were included in the study. Twenty-seven (73%) of the patients were female and 10 (27%) were male, ranging from 34 to 80 years of age, with the average age being 55.7 years. Seventeen (43.2%) of these patients were classified as ASA I and 21 (56.8%) as ASA II. A total of 142 ZIs were planned and installed in the time frame mentioned. Without distinguishing the region of the maxilla, the implants used were, on average, 1.1 mm larger in length than those initially planned. CONCLUSION: Overall, the data indicates moderate agreement between the planned and surgical lengths of the ZIs and indicates that using TDMs is a predictable and reliable preoperative planning technique of the length of posterior ZIs.

Is Intraoral Scanning Accurate to Evaluate Dental Implant Position? An In-Vitro Study.

PURPOSE: The position of dental implants is generally verified through imaging exams, even though its use exposes patients to radiation. Intraoral scanning (IOS) may be a suitable alternative to using radiographic imaging to verify implant position. Using polyurethane jaw models, the purpose of this in-vitro study was to measure and compare implant positions determined by IOS and cone-bean computed tomography (CBCT). METHODS: One hundred twenty implants were installed in 30 edentulous polyurethane jaws, 4 dental implants in each prototype. Four scanbodies were attached to the implants, and a scanning of each mandible was acquired using an intraoral scanner (CS 3600). All prototypes were also submitted to CBCT. Then, the 3D scan files in STL (Standard Tessellation Language) format were superimposed on the DICOM (Digital Imaging and Communications in Medicine) images of the tomographic mandibles. The accuracy of IOS was evaluated by the metric analyses of deviations between the position of the implants projected by the IOS versus the detected tomographically, in which CBCT served as the gold standard, using a free software for digital planning (Bluesky 4 - Grayslake, IL, USA). The following measures were analyzed: radial deviations at the shoulder (Xc) and at the apex of the implants (Xa), height deviation (Xh) and axial deviation. Bland-Altman and a paired t-test were applied to verify the reproducibility between measurements and a t-test for a mean was applied to compare the measurements with zero value. RESULTS: The results showed Xc and Xa deviation means of 0.14 ± 0.09 mm and 0.12 ± 0.12 mm, respectively. The Xh mean was 0.2 ± 0.12 mm and the axial deviation mean was 0.71° ± 0.66°. T-test showed a statistically significant difference when the 4 means were compared to zero value, represented by the CBCT (P < .0001). CONCLUSIONS: There was a statistically significant difference IN the scanned measures compared to CBCT as the standard, but the differences may not be clinically significant. The IOS utilization to evaluate the position of dental implants is a radiation-free and reproducible method, with the advantage of not generating metal artifacts. Further clinical studies are needed to validate this new method of postoperative evaluation.

Laboratorial Comparative Study of the Accuracy Between Virtual Planning and Erickson's Platform.

Purpose: The goal was to perform an orthognathic surgery laboratorial study to evaluate the reproducibility of the resulting movements from virtual surgical planning (VSP), by comparing the measurements obtained from VSP to those obtained from Erickson's platform using the 3D printed surgical guide. Methods: Eight patients who had undergone orthognathic surgery were screened and grouped according to maxillary movement and the patient's dentofacial deformity. Three-D virtual surgery simulations were performed, and surgical guides were obtained using Dolphin Imaging 11.9® software. In a semi-adjustable articulator (SAA), the maxilla model was separated from the SAA mounting platform, and the surgical guide was used to reassemble it. Then, the maxilla model was fixed and transferred to Erickson's platform to verify the planned movement. The data were submitted for statistical analysis. Results: The agreement between the methods was excellent, regardless of direction, landmark analyzed, or the amount of movement. The most considerable variation was 0.42 mm in the movement amplitude of 6 mm, and the highest mean was 0.07 mm in the region of the superior right first molar (16). Conclusion: Therefore, regardless the movement of the maxilla, no statistically significant difference was observed between the measurements obtained through VSP and Erickson's platform, demonstrating that both methods are equally accurate and reliable.

Algorithm for Treatment of Supernumerary Nasal Tooth.

ABSTRACT: The presence of a tooth in the nasal cavity is a rare condition. There is an even more rare association, which is the presence with the mineral's deposition and formation of rhinoliths. This report shows a case of rare nasal tooth associated with rhinolithiasis and describes its surgical treatment based on an algorithm. The diagnosis was made by endoscopy with the aid of computed tomography, followed by surgical endoscopy excision. The algorithm and the proposed treatment was successful in its execution and the patient presents no complaints or complications at 3 years after surgery.

Linear analysis of the nasal septum in patients treated with surgically assisted rapid maxillary expansion.

INTRODUCTION: Surgically assisted rapid maxillary expansion is a widely used surgical procedure for resolving transverse maxillary occlusal changes in patients with bone maturity. However, few studies about the postoperative morphologic alterations in the nasal cavity in its inferior portion and the nasal septum positioning exist. METHODS: The linear nasal septum measurements of 26 adult patients treated with surgically assisted rapid maxillary expansion from 2009 to 2013 were assessed through a retrospective analysis of cone-beam computed tomographies, in Digital Imaging and Communications in Medicine files, through the Dolphin Imaging program (Dolphin Imaging and Management Solutions, Chatsworth, Calif), aimed to identify significant changes during 3 time periods of the treatment: preoperative, immediately after the palatal expansion device locking (immediate postoperative), and 6-months postoperative (late postoperative). The analyses were performed in the inferior third of the nasal septum, from 4 equidistant points in anteroposterior position and height, using fixed cranial references for lateral measures of displacement. RESULTS: No significant difference was found between preoperative, immediate postoperative, and late postoperative measurements in the 4 fixed nasal septum measurements, applying the analysis of variance test with a significance level of 5%. Comparing the surgical times alone, we found no statistically significant difference between the right and left sides applying the Student t test, which also showed symmetry in the nasal septum. CONCLUSIONS: The measurements of the nasal septum did not change in the different surgical times throughout their inferior extension, and they remained symmetrical throughout patients' follow-up period.

About chin (genioplasty) surgery / Sobre cirugía del mentón (genioplastía)

Facial harmony is the consequence of a proper balance between all facial structures. The identification and classification of morphologic characteristics that detract from facial harmony is most effectively accomplished by clinical examination. The maintenance of the ratios between the facial thirds, correct spatial bone position and soft tissues accommodation are all factors that directly contribute in a balanced facial profile. The chin, likewise, contributes significantly in facial balance, mainly in the profile view. Expressive changes on chin position are associated with the perception of strong or delicate characters. Thus, over the years, a series of studies has been constructed focusing on mandibular osteotomies techniques that enable changes in chin position: advances, setback, extrusion, intrusion, widening, narrowing and asymmetry. This study aims to address historical and technical aspects of genioplasty; associating patient's condition with the surgical techniques that can be applied for correction of chin deformities.

La armonía facial es la consecuencia del balance entre las estructuras facial. La identificación y clasificación de las características morfológicas que están acompañando la armonía facial son mas efectivas al realizar un estudio de análisis facial. La obtención de promedios entre los tercios, corrección especial de la posición del hueso y la acomodación de los tejidos blandos son factores directamente involucrados en el balance del perfil. El mentón, contribuye significativamente en este balance. Cambios expresivos en la posición del mentón son asociados con la percepción de características fuertes o delicadas. Durante los años, una serie de estudios han sido desarrollados enfocándose en las osteotomías mandibulares y técnicas capaces de alcanzar los cambios en la posición del mentón: avances, retrocesos, extrusiones, ensanchamientos, estrechamientos y asimetrías. Este estudio pretende orientar las condiciones históricas y técnicas respecto de la genioplastia; la asociación de las características del paciente con la técnica quirúrgica pueden ser aplicadas para la corrección de las deformidades.

Comparison of two anorganic bovine bone in maxillary sinus lift: a split-mouth study with clinical, radiographical, and histomorphometrical analysis.

BACKGROUND: Anorganic bovine bone (Bio-Oss®) has been extensively used for reconstruction of posterior area of maxilla in sinus lift procedure; however, a new graft material (Lumina-Bone Porous®), that has a different manufacturing process, has not been yet compared in clinical and histological terms. The manufacturing process of bovine bone graft is related to size and porosity of the particles, and this can change osteoconductive property of the material and bone formation. The use of Lumina-Porus® could improve bone formation, reduce the remaining particles of the biomaterial using a low-cost material. The aim of this research was to compare the clinical, radiological, and histomorphometrical results from maxillary sinus lift with two different anorganic bovine bone substitutes Bio-Oss® (control) and Lumina-Bone Porous® (test). RESULTS: A split-mouth study was performed with 13 volunteers. The mean bone ridge height in the deepest portion of maxillary sinuses floor was 3.11 ± 0.83 mm in the Bio-Oss® and 2.38 ± 0.75 mm in the Lumina-Bone Porous®. After sinus lift, the Bio-Oss® group shows bone ridge height of 11.56 ± 2.03 mm and Lumina-Bone® of 10.62 ± 1.93 mm. The increase in alveolar bone height scores was significant between pre-augmentation and 6 months after SL in both groups (p < 0.001). No statistical significant difference in newly formed bone in the Bio-Oss® group (20.4 ± 5.4%), and Lumina-Bone Porous® (22.8 ± 8.5%) was histomorphological observed (p > 0.05). On the other hand, the residual graft particles showed significant difference between the Bio-Oss® group (19.9 ± 8.6%) and Lumina-Bone Porous® (14.6 ± 5.6%) (p < 0.05). The survival rate of dental implants for augmented area with Lumina Bone Porous® was 88.88%, while for Bio-Oss® group was 100%. CONCLUSION: Both materials Bio-Oss® and Lumina-Bone Porous® can be used in the maxillary sinus floor augmentation with good predictability in clinical, radiographical, and histological point of view.

Clinical and immunohistochemical study of melanotic neuroectodermal tumor of infancy in the maxilla.

Melanotic neuroectodermal tumor of infancy is a rare and fast-growing neoplasm. In this study, we describe the case of a 6-month-old female patient, who presented swelling in the anterior maxilla. Tomographic reconstruction showed an unilocular hypodense and expansive area associated with the upper right central primary incisor. The presumptive diagnoses were dentigerous cyst, adenomatoid odontogenic tumor, melanotic neuroectodermal tumor of infancy and rhabdomyosarcoma, and an incisional biopsy was performed. Microscopically, the lesion revealed a biphasic cell population, consisting of small, ovoid, neuroblastic-like cells and epithelioid cells containing melanin. Immunohistochemically, the melanocyte-like component was strongly and diffusely positive for HMB-45 and Melan-A, but weakly positive for S100. Based on these findings, definitive diagnosis of melanotic neuroectodermal tumor of infancy was established. Then, enucleation of the lesion was performed by careful curettage. After 2 year follow-up, no clinical or radiographical evidence of recurrence was verified. The present case highlights the importance of early diagnosis and therapeutic intervention at the appropriate time to achieve a favorable outcome for the patient.

Clinical and immunohistochemical study of melanotic neuroectodermal tumor of infancy in the maxilla / Estudo clínico e imuno-histoquímico de tumor neuroectodérmico melanocítico da infância em maxila

ABSTRACT Melanotic neuroectodermal tumor of infancy is a rare and fast-growing neoplasm. In this study, we describe the case of a 6-month-old female patient, who presented swelling in the anterior maxilla. Tomographic reconstruction showed an unilocular hypodense and expansive area associated with the upper right central primary incisor. The presumptive diagnoses were dentigerous cyst, adenomatoid odontogenic tumor, melanotic neuroectodermal tumor of infancy and rhabdomyosarcoma, and an incisional biopsy was performed. Microscopically, the lesion revealed a biphasic cell population, consisting of small, ovoid, neuroblastic-like cells and epithelioid cells containing melanin. Immunohistochemically, the melanocyte-like component was strongly and diffusely positive for HMB-45 and Melan-A, but weakly positive for S100. Based on these findings, definitive diagnosis of melanotic neuroectodermal tumor of infancy was established. Then, enucleation of the lesion was performed by careful curettage. After 2 year follow-up, no clinical or radiographical evidence of recurrence was verified. The present case highlights the importance of early diagnosis and therapeutic intervention at the appropriate time to achieve a favorable outcome for the patient.

RESUMO O tumor neuroectodérmico melanocítico da infância é uma neoplasia rara e de crescimento rápido. Neste estudo, relata-se o caso de uma paciente do sexo feminino de 6 meses de idade, que apresentou tumefação na região anterior de maxila. A reconstrução tomográfica revelou área unilocular hipodensa e expansiva associada ao incisivo central superior direito decíduo. Realizou-se biópsia incisional, considerando as hipóteses diagnósticas de cisto dentígero, tumor odontogênico adenomatoide, tumor neuroectodérmico melanocítico da infância e rabdomiossarcoma. Microscopicamente, a lesão revelou população celular bifásica, consistindo de células pequenas, ovoides, de aparência neuroblástica, e de células epitelioides, contendo melanina. A análise imuno-histoquímica demonstrou que o componente celular contendo melanina era positivo de forma intensa e difusa para HMB-45 e Melan-A, mas levemente positivo para S100. Com base nestes achados, foi estabelecido o diagnóstico definitivo de tumor neuroectodérmico melanocítico da infância. Em seguida, foi realizada a enucleação da lesão com curetagem cuidadosa. Após 2 anos de acompanhamento, não foram verificadas evidências clínicas ou radiográficas de recorrência. O presente caso destaca a importância do diagnóstico precoce e da intervenção terapêutica no momento apropriado, a fim de alcançar um desfecho favorável para o paciente.

Preservação da crista alveolar através da utilização de membrana densa de politetrafluoretileno / Preservation of the alveolar crest through the use of polytetrafluoroethylene dense membrane

O processo de remodelação óssea que inicia-se após a extração de um dente pode dificultar a reabilitação através de implantes dentários. Nesse sentido, a técnica de regeneração óssea guiada (ROG), com o uso de membrana não reabsorvível, busca minimizar estes efeitos, favorecendo a cicatrização do alvéolo e diminuindo a necessidade de enxertos ósseos. Sendo assim, o objetivo deste trabalho foi avaliar a utilização da membrana densa de politetrafluoretileno (d-PTFE) em alvéolos pós-extração. Para isso, 8 pacientes que foram submetidos à remoção de elemento dentário receberam em seus alvéolos a colocação da membrana d-PTFE. A mesma foi posicionada sobre o alvéolo imediatamente após a extração e deixada no local por 21 dias. Para avaliar a preservação do rebordo alveolar, tomografias foram realizadas no pré-operatório e no pós-operatório de 90 dias. Os resultados mostraram uma efetiva preservação do rebordo alveolar proporcionado pelo uso da membrana. A perda óssea em espessura dos alvéolos foi de apenas 0,32 mm, em média. Já a perda óssea em altura foi de 0,79 mm, em média. Oito implantes foram instalados, sendo que nenhuma complicação ou perda de implantes foi observada. A membrana de PTFE denso mostrou-se efetiva na manutenção da arquitetura alveolar, minimizando a perda óssea em altura e espessura (AU).

The process of bone remodeling that begins after the extraction of a tooth can make rehabilitation difficult through dental implants. In this sense, the technique of guided bone regeneration (ROG), with the use of a non-resorbable membrane, seeks to minimize these effects, favoring healing of the alveolus and reducing the need for bone grafts. Therefore, the objective of this work was to evaluate the use of polytetrafluoroethylene dense membrane (d-PTFE) in post-extraction alveoli. For this, 8 patients who were submitted to tooth removal, received in their alveoli the placement of the d-PTFE membrane. It was placed on the alveolus immediately after extraction and left in place for 21 days. To evaluate the preservation of the alveolar ridge, CT scans were performed preoperatively and postoperatively for 90 days. The results showed an effective preservation of the alveolar ridge provided by the use of the membrane. The bone loss in the alveoli thickness was only 0.32 mm on average. The bone loss in height was 0.79 mm on average. Eight implants were installed, and no complications or loss of implants were observed. The dense PTFE membrane was effective in maintaining the alveolar architecture, minimizing bone loss in height and thickness (AU).

Failure of Osseointegrated Dental Implant After Alveolar Nerve Transposition: A Report of an Unusual Complication and Surgical Management.

PURPOSE: To describe an unusual case of mandibular fracture after osseointegrated dental implant removal placed after inferior alveolar nerve transposition. REPORT OF CASE: The patient underwent inferior nerve transposition for implant placement due to lack of interarch space. Two months after metal-ceramic crowns installation, the patient began to complain of pain in the region of the implant. In an attempt to remove the implant, there was a fracture of the implant, and only two third of it was removed, leaving only the apical portion of the implant in the mandible. The patient opted for the total removal of implant. At 15 days of follow-up, the patient returned with mandibular fracture, which was treated through an internal fixation with a titanium reconstruction plate of 2.0-mm thickness with locking screws. CONCLUSION: The inferior alveolar nerve transposition may represent the only rehabilitation option, especially in cases where there is insufficient bone remaining for installation of short implants with reduced interarch space.

Retrospective Analysis of 129 Consecutive Zygomatic Implants Used to Rehabilitate Severely Resorbed Maxillae in a Two-Stage Protocol.

PURPOSE: To report on the clinical outcome of 129 zygomatic implants placed in 37 patients with severely resorbed partially or completely edentulous maxillae. MATERIALS AND METHODS: Patients who received zygomatic implants between 2007 and 2014 were included in this retrospective analysis. All patients were treated using the same surgical protocol, the sinus slot technique. The following data were recorded: sex, age, race, medical history, etiology, addictions, degree of bone atrophy, type and size of zygomatic implants, number of implants placed, type of prosthesis, survival rate, and success of implants and complications. Follow-up included standardized clinical and tomography examinations. RESULTS: Thirty-seven consecutive patients (25 women, 12 men; mean age 55.64 years [range 40 to 77 years]) were treated. All were in need of oral reconstruction and had maxillary atrophy that warranted zygomatic implant placement. One hundred twenty nine zygomatic implants were placed in these 37 patients. Two of the implants failed, resulting in a cumulative survival rate of 98.44%. Maxillary sinusitis was the most common complication found (21.62%); however, neither of the implant failures was related to sinusitis or smoking. CONCLUSION: The zygomatic implant is a reliable option for treatment of the severely resorbed maxilla.

Mandibular Osteolytic Lesion Associated with Exuberant Hyaline Ring Granuloma Reaction.

OBJECTIVE: To report an unusual case of oral hyaline ring granuloma (HRG) that caused an extensive osteolytic lesion. CLINICAL PRESENTATION AND INTERVENTION: A 22-year-old female was referred to our hospital with a large expansile cystic lesion in the left mandibular ramus associated with a clinically visible, partially erupted third molar. A diagnosis of paradental cyst was made. After marsupialization of the lesion, histopathological analysis of the surgical specimen showed an unusual exuberant HRG reaction supported by scarce fibrous stroma. CONCLUSION: This was a case of exuberant HRG reaction that caused extensive bone destruction.

Histologic and Histometric Analysis of Bone Repair at the Site of Mandibular Body Osteotomy and at the Bone-Screw Interface After Using a Biodegradable 2.0-mm Internal Fixation System.

The aim of the study was to evaluate histologically and histometrically the bone repair at the mandibular body osteotomy and at the bone-screw interface after using a biodegradable 2.0-mm internal fixation system. Six dogs were subjected to an osteotomy in the mandibular body, which was stabilized by applying a fixation device manufactured with poly-L-DL-lactic acid (70:30). The dogs were euthanized at 2 and 18 weeks. Each screw was sectioned along its long axis, and the osteotomy sites were divided into 3 parts: the upper part was labeled the tension third (TT); the lower part, compression third (CT); and the part between the TT and CT, intermediary third (IT). Histologic analysis showed areas of direct contact between the screw surface and the parent lamellar bone at 2 weeks. At 18 weeks, 3 microscopically distinct layers at the bone-screw interface were noted. At the osteotomy sites, union between the bone fragments was observed at 18 weeks. Statistically significant differences in the newly formed bone among TT, IT, and CT (P = 0.019) were observed. In conclusion, the biomechanical environment created by the biodegradable IF system used in this study facilitated bone repair at the osteotomy site.

Use of a titanium mesh "shelter" combined with the soft tissue matrix expansion (tent pole) grafting in the reconstruction of a severely resorbed edentulous mandible. Technical note.

Patients wearing complete dentures for a long time usually exhibit lack of bone and keratinized mucosa in the bearing area due to bone resorption. The patients suffering from this phenomenon usually have unstable and non-retentive complete denture, which result in constant trauma to the mucosa, pain, functional limitations and worsening of facial esthetics. An innovative technique has been described in which a novel surgical approach using osseointegrated dental implants as "tent poles" was applied concomitant with particulate autogenous bone graft. The authors claim that the control and maintenance of the surgically expanded soft tissue volume should prevent graft resorption in the long term. Nevertheless, resorption of the bone graft is usually more significant where the bone mass is poorer, in the mandibular body. This paper describes a case of severely resorbed edentulous mandible in which the "tent pole" technique was applied with some modifications. Use of the titanium mesh "shelters" and two additional implants was effective in "protecting" the bone graft in the posterior portion of the mandibular body increasing bone mass volume in this area. Furthermore, we believe that this kind of graft "protection" on the whole residual alveolar ridge can increase the width of bone mass gain optimizing the "tent pole" technique.

Use of a Titanium Mesh "Shelter" Combined with the Soft Tissue Matrix Expansion (Tent Pole) Grafting in the Reconstruction of a Severely Resorbed Edentulous Mandible. Technical Note.

Patients wearing complete dentures for a long time usually exhibit lack of bone and keratinized mucosa in the bearing area due to bone resorption. The patients suffering from this phenomenon usually have unstable and non-retentive complete denture, which result in constant trauma to the mucosa, pain, functional limitations and worsening of facial esthetics. An innovative technique has been described in which a novel surgical approach using osseointegrated dental implants as "tent poles" was applied concomitant with particulate autogenous bone graft. The authors claim that the control and maintenance of the surgically expanded soft tissue volume should prevent graft resorption in the long term. Nevertheless, resorption of the bone graft is usually more significant where the bone mass is poorer, in the mandibular body. This paper describes a case of severely resorbed edentulous mandible in which the "tent pole" technique was applied with some modifications. Use of the titanium mesh "shelters" and two additional implants was effective in "protecting" the bone graft in the posterior portion of the mandibular body increasing bone mass volume in this area. Furthermore, we believe that this kind of graft "protection" on the whole residual alveolar ridge can increase the width of bone mass gain optimizing the "tent pole" technique.

Pacientes portadores de próteses totais por um longo período geralmente apresentam perda significativa de osso do processo alveolar e de mucosa ceratinizada na área chapeável devido ao processo de reabsorção óssea associada com a perda de função. Estes pacientes geralmente possuem próteses totais sem retenção e estabilidade, o que resulta em trauma crônico à mucosa, limitações funcionais e piora da estética facial. Uma técnica cirúrgica inovadora foi descrita na qual implantes osseointegráveis são posicionados em forma de "pilares" conjuntamente com enxerto ósseo autógeno particulado. Os autores afirmam que o controle e manutenção do volume tecidual obtido cirurgicamente diminui a perda em volume do enxerto ósseo utilizado. Entretanto esta reabsorção geralmente ocorre com maior intensidade onde a massa óssea é mais pobre, ou seja, em corpo mandibular. Este artigo descreve um caso onde uma mandíbula severamente reabsorvida foi reconstruída utilizando-se a técnica de "tent pole" com algumas modificações propostas pelos autores. O uso da malha de titânio em forma de "cabana" e dois implantes dentários osseointegráveis adicionais contribuíram para "proteger" o enxerto ósseo autógeno na região posterior do corpo mandibular aumentando o volume ósseo na região. Adicionalmente, nós acreditamos que o uso deste tipo de proteção em todo rebordo alveolar residual pode melhorar o ganho de massa óssea otimizando, portanto, a técnica original de "tent pole".

Bone tissue response to plasma-nitrided titanium implant surfaces.

A current goal of dental implant research is the development of titanium (Ti) surfaces to improve osseointegration. Plasma nitriding treatments generate surfaces that favor osteoblast differentiation, a key event to the process of osteogenesis. Based on this, it is possible to hypothesize that plasma-nitrided Ti implants may positively impact osseointegration. Objective The aim of this study was to evaluate the in vivo bone response to Ti surfaces modified by plasma-nitriding treatments. Material and Methods Surface treatments consisted of 20% N2 and 80% H2, 450°C and 1.5 mbar during 1 h for planar and 3 h for hollow cathode. Untreated surface was used as control. Ten implants of each surface were placed into rabbit tibiae and 6 weeks post-implantation they were harvested for histological and histomorphometric analyses. Results Bone formation was observed in contact with all implants without statistically significant differences among the evaluated surfaces in terms of bone-to-implant contact, bone area between threads, and bone area within the mirror area. Conclusion Our results indicate that plasma nitriding treatments generate Ti implants that induce similar bone response to the untreated ones. Thus, as these treatments improve the physico-chemical properties of Ti without affecting its biocompatibility, they could be combined with modifications that favor bone formation in order to develop new implant surfaces.