Orbital Implants Insertion to Improve Ocular Prostheses Motility

The objectives of this study were, through a literature review, to point the differences between orbital implants and their advantages and disadvantages, to evaluate prosthesis motility after orbital implants are inserted, and to point the implant wrapping current risks. Sixty-seven articles were reviewed. Enucleation implants can be autoplastics or alloplastics and porous (including natural and synthetic hydroxyapatite [HA]) or nonporous (silicone). Hydroxyapatite is the most related in the literature, but it has disadvantages, too, that is, all orbital implants must be wrapped. Exposure of the porous orbital implant can be repaired using different materials, which include homologous tissue, as well as autogenous graft, xenograft, and synthetic material mesh. The most used materials are HA and porous polyethylene orbital implant. The HA implant is expensive and possibly subject corals to damage, different from porous polyethylene orbital implants. Porous implants show the best prosthesis motility and a minimum rate of implants extrusion. Implant wraps can facilitate smoother entry of the implant into the orbit and allow reattachment of extraocular muscles. They also serve as a barrier between the overlying soft tissue and the rough surface of the implant, protecting implants from exposure or erosion.

Rehabilitation with ear prosthesis linked to osseointegrated implants

Background: The absence of an ear, which can be the result of a congenital malformation, surgical tumour resection or traumatic injury, is a significant aesthetic problem. Attachment of ear prostheses with adhesives can cause local irritation for the wearer and affect the colour of the prostheses. Use of implants in craniofacial reconstruction can improve the retention and stability of prostheses giving to patient greater comfort and security relative to adhesive attachment.Objective: The aim of this report was to present a clinical case of a mutilated patient who was rehabilitated by means of installing an ear prosthesis fixed through osseointegrated implants.Materials and methods: The patient had two implants installed in the mastoid region that were linked by a bar, and a clip-type system was used. The ear prosthesis was constructed from medical-use silicone, pigmented to match the patient's skin colour and linked to the retention system.Conclusion: The patient's rehabilitation was satisfactory from both a functional and an aesthetic point of view, making it possible for the patient to return to a normal social life and regain lost self-esteem.

Analysis of the effects of irradiation in osseointegrated dental implants

Objective: The purpose of the present study was to evaluate the influence of radiation in osseointegrated dental implants installed in tibiae of rats.Material and methods: Screw-shaped implants (2.5 mm diameter by 3.5 mm length) were custom made from commercially pure titanium bars. Titanium implants were blasted and sterilized before implantation. Animals were divided into two groups of 12 animals each and the rats were not paired after the groups' formation. The experimental group (group 1) received external irradiation 4 weeks after surgery while in the control group (group 2) animals were kept free of radiation. The shear strength required to detach the implant from bone was measured by push-out testing and osseointegration was histologically evaluated.Results: Results showed that the compressive strength of irradiated implants (33.49 MPa) was significantly lower than the compressive strength of non-irradiated implants (48.05 MPa).Conclusions: We concluded that the mechanical strength bonding between implants and host tissues decreased after irradiation.

Stability of cp-Ti and Ti-6Al-4V alloy for dental implants as a function of saliva pH - an electrochemical study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of the influence of location of osseointegrated implants associated with mandibular removable partial dentures

Purpose: The aim of this research was to assess, by means of, the bi-dimensional finite element method, the best implant location in the alveolar edge, through stress distribution and support structure displacement of a distal extension removable partial denture associated with an osseointegrated implant of 10.0 x .75 mm, acting as abutment for the denture base.Methods and Materials: Five models in sagittal cut were used to represent: model A-hemi arch containing natural tooth 33 and the distal alveolar edge; model B-similar to model A, but with a conventional removable partial denture to replace the absent teeth; model C (MC)-similar to the previous one, with an implant in the distal region of the edge under the denture base; model D-similar to MC, with the implant in the central region of the edge; model E-similar to MC, with an implant in the mesial region of the edge. With the aid of the finite element program ANSYS 8.0, the models were loaded with strictly vertical forces of 50 N on each cusp tip. Displacement and von Mises Maps were plotted for visualization of results.Results: The introduction of implant diminished the tendency of intrusion of the removable partial denture in all situations. The maximum stress was observed on implant in all situations. Approximating implant in direction of support teeth was benefit for stress distribution.Conclusion: Model D presented the lowest value for maximum tendency to displacement when compared with those found in the other models; model E demonstrated better relief with regard to demand from the abutment tooth; locating the implant near of the abutment tooth influenced positively the distribution of stresses on the analyzed structures.

The use of transitional implants to support provisional prostheses during the healing phase: a literature review

Objective: Transitional implants are indicated for cases in which immediate loading is counter-indicated because a healing period is necessary for osseointegration of the definitive implants. These provisional implants were developed to support an implant-supported fixed prosthesis or overdenture to provide retention, stability, and support. The aim of this article was to conduct a literature review on transitional implants to highlight the characteristics of the transitional implants and their advantages, indications, and contraindications, including the level of osseointegration of such implants according to the functional period. Method and Materials: The present literature review was based on the OldMedline and Medline databases from 1999 to 2010 using the key words "transitional implants" and "temporary implants." Fourteen articles were found: 11 clinical studies or techniques and three histologic and histomorphometric studies. Results: The transitional immediate prostheses were worn by completely and partially edentulous patients. Advantages of transitional implants include complete denture retention, stability, and support; maintenance of chewing, phonetics, and patient comfort; protection of bone grafts; vertical stop during healing period; easy and fast surgical and prosthetic procedures; lower cost in comparison to the definitive implant; and reestablishment of esthetics. The success of transitional implants as conservative treatment for conventional immediate loading is a reality if correctly indicated. Conclusion: Transitional implants are a provisional treatment alternative for completely and partially edentulous patients. However, additional studies are required to evaluate the level of remodeling and repair of the transitional implants under loading. (Quintessence Int 2011; 42: 19-24)

Prosthetic transfer impression accuracy evaluation for osseointegrated implants

Purpose: The objective of this study was to evaluate and compare 3 impression techniques for osseointegrated implant transfer procedures.Materials and Methods: (1) Group Splinted with Acrylic Resin (SAR), impression with square copings splinted with prefabricated autopolymerizing acrylic resin bar; (2) Group Splinted with Light-Curing Resin (SLR), impression, with square copings splinted with prefabricated light-curing composite resin bar; (3). Group Independent Air-abraded (IAA), impression with independent square coping aluminum oxide air-abraded. Impression procedures were performed with polyether material, and the data obtained was compared with a control group. These were characterized by metal matrix (MM) measurement values of the implants inclination positions at 90 and 05 degrees in relation to the matrix surface. Readings of analogs and implant inclinations were assessed randomly through graphic computation AutoCAD software. Experimental groups angular deviation with MM were submitted to analysis of variance and means were compared through Tukey's test (P < 0.05).Results: There was no statistical significant difference between SAR and SLR experimental groups and MM for vertical and angulated implants. Group IAA presented a statistically significant difference for angulated implants.Conclusion: It was concluded within the limitations of this study, that SAR and SLR produced more accurate casts than IAA technique, which presented inferior results.

Craniofacial Implants Success in Facial Rehabilitation

The use of craniofacial implants is an effective treatment for patients with deformities, burns, and cancer sequelae. The sites with the most successful implants are the auricular, nasal, and orbital regions. Furthermore, other factors can affect the implant longevity such as irradiated area, surgical technique, bone quality and quantity, macrostructure and microstructure of the implant, maintenance, and systemic factors.

Mobility, Aesthetic, Implants, and Satisfaction of the Ocular Prostheses Wearers

During the process of facial rehabilitation, the mobility of ocular prostheses must be considered. Whereas some factors depend exclusively on the dentist, such as molding techniques and selection of material for denture construction, regarding ocular rehabilitation, factors, such as type of surgery, whether to adopt implants, and the use of lubricants, deserve special attention owing to their integration and their association with other factors pertaining exclusively to the patient. To establish harmony, and with the intention of aiding the dentist, after a discerning evaluation, the authors of this study report the factors that provide greater or less mobility to ocular prostheses and conceal the prosthesis in a more natural way, thereby contributing toward achieving a favorable aesthetic result in rehabilitations.

Radiographic assessment of bone density around integrated titanium implants after ovariectomy in rats

Objectives:This study evaluated the influence of ovariectomy 8 weeks after implant placement on bone integrated to titanium implants.Materials and methods:Thirty-eight female rats were submitted to a titanium implant at the tibiae proximal methaphysis. After a healing period of 8 weeks the animals were randomly divided into three groups: control (CTL-10 animals), sham-operated (SHAM-14 animals) and ovariectomy (OVX-14 animals). The CTL group was then sacrificed in order to confirm integration of the implant. The SHAM group was submitted to fictitious surgery and the OVX group was submitted to bilateral ovariectomy. After 12 weeks post-implant placement, the SHAM and OVX groups were sacrificed. In order to confirm the systemic osteopenia in rats, a dual-energy X-ray absorptiometry (DXA) was performed. For the evaluation of bone density, digital radiographs were taken. The grey level of the bone adjacent to implant was measured using image software and the bone density was calculated at six points on both sides of the implant.Results:Densitometry measurements of the femur confirmed systemic bone mass loss in the OVX group. Individualized bone analyses of different regions surrounding the implant showed a significantly lower radiographic bone density (P < 0.05) in the cancellous region of the OVX group (77.48 +/- 23.39 grey levels) when compared with the CTL and SHAM groups (91.61 +/- 32.10 and 102.57 +/- 32.50 grey levels, respectively).Conclusions:The present study showed a decrease of the radiographic bone density in the cancellous region of bone around titanium implants placed 8 weeks before ovariectomy in rats.

Analysis of failed commercially pure titanium dental implants: A scanning electron microscopy and energy-dispersive spectrometer X-ray study

Background: the failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure.Methods: Twenty-one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 +/- 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant.Results: SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium.Conclusion: These preliminary results do not suggest any material-related cause for implant failures, although different element composition was assessed between failed implants and control implants.

Influence of cyclosporin A on quality of bone around integrated dental implants: a radiographic study in rabbits

To evaluate the influence of cyclosporin A (CsA) administration on bone around integrated dental implants assessed by a bone quality index and by quantitative subtraction radiography.A total of 36 machine surface commercial implants were placed in 18 adult rabbits. After a 3-month healing period without any disturbance, the animals were randomly divided into three groups of six animals each. Group A was sacrificed at this time. CsA was injected subcutaneously in an immunosuppressive dose of 10 mg/kg/day in a test group (Group T), and a Group B served as a control, receiving only vehicle. After 3 months of cyclosporin administration, the animals of both Groups B and T were sacrificed. Radiographs were obtained at implant surgery and at the day of sacrifice with a CMOS sensor. Bone quality around the implants was compared between the groups using a bone quality index and quantitative subtraction radiography.The bone analysis showed that in Group T, the bone quality changed dramatically from a dense cortical to a loose trabecular bone structure (P < 0.0001, chi(2) test) while in Groups A and B there were no significant differences. Quantitative digital subtraction radiography showed significantly (P < 0.05) lower gray shade values (radiographic density) in a region of bone formation around the implants in Group T (118 +/- 12) than in Groups A (161 +/- 6) and B (186 +/- 10).Within the limits of this study, CsA administration has a negative effect on the quality of bone around integrated dental implant.

Histomorphometric analysis of tissue responses to bioactive glass implants in critical defects in rat calvaria

The aim of this study was to evaluate the osteogenic behavior of two chemically similar bioactive glass products (Biogran (R) and Perioglas (R)) implanted in critical bone defects in rat calvaria. Thirty-six transfixed bone defects of 8 mm diameter were made surgically in adult male Wistar rats. The animals were distributed equally into three groups: Biogran (GI), Perioglas (GII) and without implant material (control; GIII). The morphology and composition of both bioactive glasses were analyzed by scanning electron microscopy and energy-dispersive spectrometry. Tissue specimens were analyzed at the biological time points of 15, 30 and 60 days by optical microscopy and morphometry, demonstrating biocompatibility for the tested materials with moderate chronic inflammation involving their particles. Bone neoformation resulted only as a reparative reaction to an intentionally produced defect and was limited to the defect's edges. No statistically significant differences among the groups were observed. At the scar interstice, abundant deposits of collagenous fibers enveloping the particles were noted. The present results indicated that the bioactive glasses, under the experimental conditions analyzed, did not show osteogenic behavior. Copyright (c) 2007 S. Karger AG, Basel.

Multidisciplinary approach for the aesthetic treatment of maxillary lateral incisors agenesis: thinking about implants?

Missing maxillary lateral incisors create an esthetic problem with specific orthodontic and prosthetic considerations. Implants are commonly used to replace congenitally missing lateral incisors in adolescent orthodontic patients. However, an interdisciplinary approach should be observed during the diagnosis, prognosis, and treatment plan to provide a result with good predictability and meet the esthetic and functional expectations of the patient. The present study describes a case of a young patient with tooth agenesis of maxillary lateral incisors, which was conducted with an integrated planning. After 5-year follow-up of 2 fixed implant-supported prostheses, clinical and radiographic examination showed the treatment to be successful. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:e22-e28)