Influência da dentina bovina e do dispositivo de microtração na resistência de união de sistemas adesivos

Pós-graduação em Odontologia Restauradora - ICT

Estudo de propriedades da resina acrílica termoativada por energia de micro-ondas frente às variações nos procedimentos de inclusão

On heat cured acrylic resins by microwaves energy the action of electromagnetic waves on methylmethacrylate promote the polymerization process. However, part of this energy is absorbed by the gypsum present in the flask and the function of this gypsum is to maintain the characteristics of specimen, nevertheless is unknown in the literature as the amount of water present in this gypsum affects the characteristics of acrylic resin. The proposal of this study was verified if dried gypsum influenced in some properties of the acrylic resins thermally activated by microwaves: presence of porosity, microhardness, roughness, flexural strength and dimensional change. Two different types of acrylic resin for complete denture were utilized: Lucitone 550 e Vipi-Wave and groups were formed: Lucitone 550, polymerization by microwave energy without gypsum treatment; Lucitone 550, polymerization by microwave energy with pretreatment gypsum; Vipi-Wave by microwave energy without gypsum treatment; Vipi Wave, polymerization by microwave energy with pretreatment gypsum; Lucitone 550 control group polymerization in hot water bath. For both situations were performed analysis of microhardness and porosity three different metallic shaped specimens were formed with followed dimensions: 2,0x2,0x2,0cm (8cm3); 2,0x2,0x1,0 (4cm3) e 2,0x2,0x0,5 (2cm3). Standardized wax specimens was used to prepare groups (n=9) and included in glass fiber flasks. The gypsum dry was made by microwave oven cycle (10min and 600W) and then the flasks were maintained in dry oven during two hours. Polymerizations of specimens were made and then polished. Wax patterns #7 obtained from the metal were embedded in plastic flask and following the processes of pressing and polymerization of the resin according to established groups. To evaluate the flexural strength, specimens 65mm x 10mm x 3.0mm from metallic patterns in bar format were made. ...

Gingival squamous cell carcinoma: a case report

Squamous cell carcinoma is a malignant epithelial neoplasm characterized by variable clinical manifestations. When located in the gingiva, this neoplasm may mimic common inflammatory lesions. The aim of this study was to report a case of atypical squamous cell carcinoma, in which the patient had no risk factors for the development of this neoplasm. A 61 year old Caucasian female was seen with a 3 month history of a rapidly growing, painful nodule in the gingiva adjacent to tooth #11. Clinical examination revealed a proliferative lesion in the vestibular marginal gingiva of teeth #11 and #12, presenting with purulent exudation. Thus, in view of the clinical symptoms and differential diagnosis of an infectious granulomatous process and malignant neoplasm, an incisional biopsy was obtained from the lesion. The diagnosis of squamous cell carcinoma was made and fourteen days after incisional biopsy, healing was found to be unsatisfactory. The patient was referred for treatment consisting of surgical excision of the tumour. A removable partial denture was fabricated for rehabilitation, one month after surgery of the maxilla; the patient was submitted to dissection of the regional lymph nodes and radiotherapy for an additional 3 months. Three years after the end of treatment, the patient continues to be followed-up and does not show any sign of recurrence. Gingival squamous cell carcinoma is a condition which chance of cure is higher when carcinomatous lesions are diagnosed and treated early. In this instance dentists play an important role in early detection of gingival squamous cell carcinoma.

Fatores biomecânicos relevantes na seleção dos grampos em próteses parciais removíveis com extremo livre: estudo clínico

The free-end removable partial dentures (RPD) shows a complicated and peculiar biomechanical behavior that impose high occlusion forces to the abutment teeth. By this way, the aim of this study was to evaluate the several factors that influence the clasps indication to free-end RPD. It was analysed 84 designed and planned study models of 71 patients, involving 130 clasps near-by a free-end; followed by clinical and radiographical informations. It was observed that bar clasps (“T”, “Tmod”, “i”) were used in 88.46% of abutment teeth. In the others (11.55%), it was used simple, combinated or ring circumferential clasps, and MDL. In abutment teeth with high equator line the “i” clasps were predominant (48.48%). The “Tmod” clasps were predominant in abutment teeth with low equator line (50%) or in middle third (51.35%) and “T” clasps were predominant in inclined equators with mesio-buccal (56.52%) or disto-buccal (66.66%) retention. In the posterior abutment teeth, it was prevalent the distal rest (63.52%) and embracing to the adjacent tooth. Some others factors like long clinical crown (5.38%), wrong position of abutment teeth (4.61%), aesthetics (3.07%), retention in alveolar ridge (2.3%), fragility of abutment teeth (1.53%), short clinical crown (0.76%) and short space to the clasp (0.76%) influenced directly during the clasps selection. Factors like mobility of abutment teeth, height of muscular insertions, depth of buccal fornix and antagonist arch acted like secondary factors. After the informations analysis it may be concluded that the bar clasps with distal rest and embracing to the adjacent tooth were the most indicated to free-end RPD

Prótese total imediata: relato de caso clínico

The immediate complete denture is defined as a removable or partial denture made to be installed immediately after the extraction of the natural teeth. This type of prosthesis can be used for a short period of time, for aesthetic reasons, mastication, occlusal support, convenience or for the adaptation of the patients to the edentulous state, until the final prosthesis is installed. The objective of this study was to report a surgical and prosthetic rehabilitation planning of a patient by means of an immediate complete maxillary denture, and the results obtained with this treatment modality. The immediate complete denture is a necessary, well-established, useful and effective prosthetic procedure for patients who, inevitably, will present an edentulous state, despite it is a slightly more expensive and it requires more sessions for adjust

Reabilitação protética com associação entre prótese parcial removível e implante dentário: relato de caso

Removable partial denture improve functional and aesthetic failures caused by partial loss of teeth, however specific characteristics of each patients can determine the success of treatment, especially with regard to the support of the prosthesis, which may depend on teeth, the combination of teehe and mucosa and currently associated with the dental implants. The aim of this study is report a case in which there was the need of the association, to enable better aesthetics and self-esteem to the patients. After implant placement and fabrication of prosthetic patient reported satisfaction with the rehabilitation treatment, improving their quality of life.

Reabilitação Oral: prótese livre de metal, Removível e implantes. Um caso de 12 anos de acompanhamento

The literature has suggested that the association of removable partial dentures with dental implants can improve the quality of life of patients. Thus, the purpose of this study was to present a case report. This case report describes the development of a removable partial denture associated with dental implants bilaterally been monitored for 12 years, and the efficacy of the proposed treatment. The radiographic controls demonstrated no changes on bone tissue. The maxillary arch was rehabilitated with metal-free crowns. The patient was fully satisfied with this technique providing stability, esthetics, and proper function. It was concluded that the technique of using removable partial dentures associated with dental implants is viable and show the advantages of improved function, aesthetics and cost reductions in rehabilitation treatment.

Prótese parcial removível obturadora: uma reabilitação oral que devolve o bem estar físico e mental

Maxillofacial deformities may cause awkward and embarrassing bearer. These patients present serious psychological, family and social issues becoming traumatized and complexed. These deformities can have congenital origin, malformations and developmental disorders, or can be caused by pathological mutilation such as necrotizing diseases and surgical oncology, or traumas such as traffic and work accidents.

Parafunção severa: reabilitação oral com prótese total mandibular x overlay maxilar: relato de caso

In many oral rehabilitation professionals seeking venture renew people smile. However, these procedures have functional implications and aesthetic criteria which must be satisfied so that the final result is predictable. The restoration of relations intermaxillary, phonetics, masticatory function, esthetics and patient comfort are the goals to be achieved. An effective way to achieve these goals when immediate reconstruction with permanent dentures is not possible, make use of a type of partial denture called overlay. Bruxism is a manifestation of biopsychological imbalance that affects the stomatognathic system, characterized by clenching and / or attrition of teeth together so centric or eccentric, can be manifestation of nocturnal or diurnal. Its effects can manifest themselves in different parts of the stomatognathic system, varying the severity of the damage as the resistance of the structures affected, the time of existence, its regularity and the general state of the wearer. The description of the steps followed in solving this case, in which the patient edentulous mandibular arch while the maxillary arch showed absence of teeth 16 and 26 and, except for the teeth 17 and 27, all other teeth showed wear very sharp in the sense denoting incisal cervical, severe impairment of the vertical dimension, the quality of masticatory function and a marked impairment phonetic, this case report aims to guide the beginning of a rehabilitation, as well as the transitional phase of treatment for recovery of functional and aesthetic relationships intermaxillary .

Influência do formato do rebordo alveolar sagital em reabilitações com associação de prótese parcial removível de extremidade livre e implante ósseo integrado

The association of mandibular distal extension removable partial dentures with an osteointegrated implant is a treatment option at hasn't been fully explored by modern rehabilitation dentistry yet. The objective of this study is to evaluate, by means of the bidimensional method of finite elements, the distribution of tension on the structures supporting the distal extension removable partial denture (DERPD), associated to a 10.0 x 3.75 mm osteointegrated implant with an ERA retention system, in alveolar ridges of different shapes. Eight models were created, representing, from a sagittal perspective: Model A (MA) – a half arch with a horizontal ridge without posterior support, with the presence of the lower left canine, and a conventional DERPD, with metallic support in the incisal aspect of this canine, as replacement for the first and second pre-molars and the first and second molars of the lower left half arch; Model B (MB) – similar to MA, but different because of the presence of a 3.75 x 10.00 mm implant with an associated ERA retention system in the posterior region of the DERPD base; Model C (MC) - similar to MA, however with a distally ascending ridge format; Model D (MD) – similar to MC, but different because there is an implant associated to a retention system; Model E (ME) - similar to MA, however with a distally descending ridge format; Model F (MF) – similar to ME, but ditfferent in the sense that there is an implant with an associated ERA retention system; Model G (MG) – similar to MA, however with a distally descending-ascending ridge format; Model H (MH) – similar to MG, but different in the sense that there is an implant with an associated ERA retention system. The finite element program ANSYS 9.0 was used to load the models with vertical forces of 50 N, on each cuspid tip. The format of distal descending edge (ME and MF) was that presented worse results, so in the models with conventional RPD as in the models with RPD associated to the implant and ERA system of retention, for the structures gingival mucosa and tooth support. 1) the distally descending ridge presented the most significant stress in the model with the conventional RPD (ME) or with a prosthesis associated to an implant (MF) and 2) the horizontal ridge (MB) provided more relief to the support structures, such as the tooth and the spongy bone, when there was an implant associated to an ERA retention system. The incorporation of the implants with the ERA system retention, in the posterior area of the toothless edge, it promotes larger stability and retention to PPREL, improving the patient's masticatory acting and, consequently, its comfort and function.

Influencia del nivel de inserción ósea del diente soporte en el desplazamiento de PPR de extremidad libre mandibular asociada al implante oseointegrado

The rehabilitation with mandibular distal extension removable partial dentures (DERPD) is complex and the use of implants has been improving the functioning of this approach. The insertion bony level around of the last support tooth is an aggravating factor, since it can harm the longevity of the treatment. Thus, the aim of this research was to evaluate the displacement tendency of a mandibular DERPD associated to an implant, with different insertion bony levels and different connections between the RPD and the support tooth, by finite element analysis. Eight models were made: MA - DERPD, incisal rest, no bony loss; MB - DERPD, distal plate, no bony loss; MC - DERPD, incisal rest, no bony loss, with implant and ERA system; MD - DERPD, distal plate, no bony loss, with implant and ERA system; ME - DERPD, incisal rest, bony loss; MF - DERPD, distal plate, bony loss; MG - DERPD, incisal rest, bony loss, with implant and ERA system; MH - DERPD, distal plate, bony loss, with implant and ERA system. Loads of 50 N in each peak were applied. Displacement maps were obtained and showed that implant favors this association and the bony loss harms the prognostic of the prosthesis. It is concluded that: the introduction of the implant with ERA system reduced the displacement tendency of the tooth and supporting structures; introduction of distal plate reduced the movement tendency of the support tooth; the decrease of the periodontal support didn't influence significantly the displacement tendency of the models with distal plate distal, but it influenced the models with distal incisal rest.

Effect of axial loads on implant-supported partial fixed prostheses by strain gauge analysis

Objectives: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. Material and methods: Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implants applying a torque of 20 Ncm, and prefabricated Co-Cr cylinders and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n = 5). Four strain gauges (SG) were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10 Ncm torque and an axial load of 30 kg was applied at five predetermined points (A, B, C, D, E). The data obtained from the strain gauge analyses were analyzed statistically by RM ANOVA and Tukey's test, with a level of significance of p<0.05. Results: There was a significant difference for the loading point (p=0.0001), with point B generating the smallest microdeformation (239.49 με) and point D the highest (442.77 με). No significant difference was found for the cylinder type (p=0.748). Conclusions: It was concluded that the type of cylinder did not affect in the magnitude of microdeformation, but the axial loading location influenced this magnitude.

Photoelastic Analysis of Biomechanical Behavior of Single and Multiple Fixed Partial Prostheses With Different Prosthetic Connections

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of axial loads on implanted-supported partial fixed prostheses by strain gauge analysis

Objectives: The present study used strain gauge analysis to perform an in vitro evaluation of the effect of axial loading on 3 elements of implant-supported partial fixed prostheses, varying the type of prosthetic cylinder and the loading points. Material and methods: Three internal hexagon implants were linearly embedded in a polyurethane block. Microunit abutments were connected to the implants applying a torque of 20 Ncm, and prefabricated Co-Cr cylinders and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n=5). Four strain gauges (SG) were bonded onto the surface of the block tangentially to the implants, SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments with a 10 Ncm torque and an axial load of 30 kg was applied at five predetermined points (A, B, C, D, E). The data obtained from the strain gauge analyses were analyzed statistically by RM ANOVA and Tukey's test, with a level of significance of p<0.05. Results: There was a significant difference for the loading point (p=0.0001), with point B generating the smallest microdeformation (239.49 mu epsilon) and point D the highest (442.77 mu epsilon). No significant difference was found for the cylinder type (p=0.748). Conclusions: It was concluded that the type of cylinder did not affect in the magnitude of microdeformation, but the axial loading location influenced this magnitude.

Flexural Strength of Four Adhesive Fixed Dental Prostheses of Composite Resin Reinforced with Glass Fiber

Purpose: To evaluate the flexural strength of two fixed dental prosthesis (FDP) designs simulating frameworks of adhesive fixed partial prostheses, reinforced or not by glass fiber.Materials and Methods: Forty specimens, made with composite resin, were divided into 4 groups according to the framework design and the presence of fiber reinforcement: A1 - occlusal support; A2: occlusal support + glass fiber; B1: occlusal and proximal supports; B2: occlusal and proximal supports + glass fiber. The specimens were subjected to the three-point bending test, and the data were submitted to two-way ANOVA and Tukey's test (5%).Results: Group A2 (97.9 +/- 38 N) was statistically significantly different from all other experimental groups, presenting a significantly lower mean flexural strength.Conclusion: The use of glass fibers did not improve the flexural strength of composite resin, and designs with occlusal and proximal supports presented better results than designs simulating only occlusal support.