Estudo cinesiográfico da deglutição em indivíduos com dentição natural e com próteses totais

Pós-graduação em Reabilitação Oral - FOAR

Efficacy of an Oral Appliance for the Treatment of Obstructive Sleep Apnea

Purpose: The aim of this study was to validate the use of a mandibular repositioner appliance (MRA) to treat obstructive sleep apnea (OSA) and primary snoring, comparing polysomnographic and Epworth Sleepiness Scale (ESS) data obtained prior to and during MRA treatment. Materials and Methods: Sixty-three patients who presented with different degrees of OSA severity or primary snoring were fitted to a PM positioner between 2009 and 2011. The diagnosis was established by a polysomnogram (PSG) prior to treatment and after 6 months to verify the efficacy of MRA therapy. Subjective daytime sleepiness was evaluated by ESS questionnaire prior to treatment and at the follow-up. Results: Patients were divided into primary snoring and OSA groups. For the primary snoring group, PSG variables did not show significant results, except for a decrease in snoring. For the OSA group, the mean apnea-hypopnea index (AHI) was reduced from 23.0 +/- 11 to 5.3 +/- 4.0 and median ESS reduced significantly from 13.0 to 8.5. Complete response (AHI < 5) was found in 25 (40%) patients and partial response (AHI <= 10) in 27 (43%) patients. Conclusion: The findings validate the efficacy of the adjustable PM positioner for the safe treatment of OSA.

Mechanical Evaluation of Four Narrow-Diameter Implant Systems

Purpose: This study aimed to evaluate the survival probability of four narrow-diameter implant systems when subjected to fatigue loading. Materials and Methods: Seventy-two narrow-diameter implants to be restored with single-unit crowns were divided into four groups (n = 18): Astra Tech (3.5-mm diameter), with a standard connection (ASC); BioHorizon (3.4-mm diameter), with a standard connection (BSC); Intra-Lock (3.4-mm diameter), with a standard multilobular connection (ISC); and Intra-Lock (3.4-diameter), with a modified square connection (IMC). The corresponding abutments were screwed onto the implants, and standardized metal crowns (maxillary central incisors) were cemented and subjected to step-stress accelerated life testing in water. Use-level probability Weibull curves and reliability for 100,000 cycles at 150 and 200 N (90% two-sided confidence intervals) were calculated. Polarized light and scanning electron microscopes were used to access the failure modes. Results: The calculated survival probability for 100,000 cycles at 150 N was approximately 93% in group ASC, 98% in group BSC, 94% in group ISC, and 99% in group IMC. At 200 N, the survival rate was estimated to be approximately < 0.1% for ASC, 77% for BSC, 34% for ISC, and 93% for IMC. Abutment screw fracture was the main failure mode for all groups. Conclusions: Although the probability of survival was not significantly different among systems at a load of 150 N, a significant decrease was observed at 200 N for all groups except IMC.

Determinação da resistência à flexão de ligas odontológicas, utilizadas em prótese parcial fixa e prótese sobre implante, soldadas por brasagem e a laser

Pós-graduação em Odontologia Restauradora - ICT

FEA and microstructure characterization of a one-piece Y-TZP abutment

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

Effect of Ceramic Thickness and Shade on Mechanical Properties of a Resin Luting Agent

Purpose: This study aimed to investigate the influence of ceramic thickness and shade on the Knoop hardness and dynamic elastic modulus of a dual-cured resin cement.Materials and Methods: Six ceramic shades (Bleaching, A1, A2, A3, A3.5, B3) and two ceramic thicknesses (1 mm, 3 mm) were evaluated. Disk specimens (diameter: 7 mm; thickness: 2 mm) of the resin cement were light cured under a ceramic block. Light-cured specimens without the ceramic block at distances of 1 and 3mm were also produced. The Knoop hardness number (KHN), density, and dynamic Young's moduli were determined. Statistical analysis was conducted using ANOVA and a Tukey B rank order test (p = 0.05).Results: The bleaching 1-mm-thick group exhibited significantly higher dynamic Young's modulus. Lower dynamic Young's moduli were observed for the 3-mm-thick ceramic groups compared to bleaching 3-mm-thick group, and no difference was found among the other 3-mm groups. For the KHN, when A3.5 3-mm-thick was used, the KHN was significantly lower than bleaching and A1 1-mm-thick ceramic; however, no difference was exhibited between the thicknesses of the same shade.Conclusions: The dual-cured resin cement studied irradiated through the 1-mm-thick ceramic with the lightest shade (bleaching ceramic) exhibited a better elastic modulus, and there was no effect in KHN of the resin cement when light cured under different ceramic shades and thicknesses (1 and 3 mm), except when the A3.5 3-mm-thick ceramic was used.Clinical Significance: Variolink II irradiated through ceramic with the lowest chroma exhibited the highest elastic modulus; therefore, the light activation method might not be the same for all clinical situations.

Effect of Beverages and Mouthwashes on the Hardness of Polymers Used in Intraoral Prostheses

PurposeThe mechanical properties of acrylic resins used in intraoral prostheses may be altered by frequent exposure to liquids such as beverages and mouthwashes. This study aimed to evaluate the effect of thermocycling and liquid immersion on the hardness of four brands of acrylic resins commonly used in removable prostheses (Onda Cryl, QC-20, Classico, Lucitone).Materials and MethodsFor each brand of resin, seven specimens were immersed in each of six solutions (coffee, cola, red wine, Plax-Colgate, Listerine [LI], Oral B), and seven more were placed in artificial saliva (control). The hardness was tested using a microhardness tester before and after 5000 thermocycles and after 1, 3, 24, 48, and 96 hours of immersion. The results were analyzed using three-way repeated-measures ANOVA and Tukey's test (p < 0.05).ResultsThe hardness of the resins decreased following thermocycling and immersion in the solutions. Specimens immersed in cola and wine exhibited significant decreases in hardness after immersion for 96 hours, although the greatest significant decrease in hardness occurred in specimens immersed in LI. However, according to American Dental Association specification 12, the Knoop hardness of acrylic resins for intraoral prostheses should not be below 15. Thus, the median values of superficial hardness observed in most of the acrylic resins in this study are considered clinically acceptable.ConclusionsThe microhardness of polymers used for intraoral prostheses decreases following thermocycling. Among specimens immersed in beverages, those immersed in cola or wine experienced the greatest decrease in microhardness. Immersion of acrylic resins in LI significantly decreased the microhardness in relation to the initial value. Among the resins assessed, QC-20 exhibited the lowest initial hardness.

Removable Partial Dentures: Use of Rapid Prototyping

The CAD/CAM technology associated with rapid prototyping (RP) is already widely used in the fabrication of all-ceramic fixed prostheses and in the biomedical area; however, the use of this technology for the manufacture of metal frames for removable dentures is new. This work reports the results of a literature review conducted on the use of CAD/CAM and RP in the manufacture of removable partial dentures.

Clinical evaluation of failures in removable partial dentures

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

Thickness and marking quality of different occlusal contact registration strips

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

Tratamento multidisciplinar: relato de casos clínicos

Introduction: Adult patients are more prone to periodontal disease mainly caused by poor plaque control. In these patients, orthodontic movement is not contraindicated, but it is necessary to evaluate their periodontal status so that we can establish the appropriate treatment plan. Objective: The objective of this article is to describe and discuss the clinical cases of severely periodontally compromised individuals in need of oral rehabilitation. Methods: The study consisted of orthodontic treatment of two cases with periodontal involvement. After clinical and radiographic examinations, the cases were analyzed by a multidisciplinary team of Orthodontics, Periodontics and Prosthodontics, in order to provide the patient with the best possible esthetic, functional and stability outcomes. Periodontal treatment consisted of supra and subgingival scaling prior to orthodontic treatment, and regular maintenance performed on a quarterly basis throughout orthodontic movement. Activation was carried out every 45 to 50 days, with light forces. Retention remains to the present day, even after completion of the rehabilitation. Conclusion: Multidisciplinary oral rehabilitation treatment yields satisfactory results. The interaction between Orthodontics and Periodontics reveals that patients with reduced, but healthy periodontium, can receive orthodontic treatment as long as the forces applied do not exceed patient's biological limits.

Dynamic functional impression technique fo severely resorbed alveolar ridges

The process of bone resorption can reduce the volume of the alveolar crest, which makes may make difficult impression taking of the alveolar tissue and the subsequent fit of a new denture. This clinical report describes a fast and simple technique for impressions of edentulous ridges to replace complete dentures, using a temporary tissue conditioner material on the denture base. The existing denture must cover the whole supporting area and should be in harmony with the adjacent oral structures. This technique reduces the number of steps involved and minimizes treatment time and expenses.

A survey of the management of patients with temporomandibular disorders by general dental practitioners in southern Brazil

Purpose: Temporomandibular disorders (TMD) are recognized as one of the mostcontroversial topics in dentistry, despite the fact that both basic science and clinicalresearchers have currently reached some degree of consensus. This study aimed toconduct a questionnaire-based survey about the management of TMD patients bygeneral dental practitioners (GDPs).Materials and Methods: One hundred fifty-one GDPs with a private practice in a cityof southern Brazil were included, independent of school of origin, gender, graduationyear, and curriculum content. All participants were administered a questionnaire aboutthe management of patients with TMD, and the responses were analyzed by binomialand chi-square tests (α = 0.05).Results: Of the GDPs, 88.7% received TMD patients, who were primarily diagnosedon the basis of medical history (36.6%) or physical examination (30.4%). Of these,65.4% referred the patients elsewhere, primarily to specialists in occlusion (36.1%) ororthodontics (29.7%). Occlusal splinting was the most commonly used managementmodality (20.8%), followed by occlusal adjustment (18.1%) and pharmacotherapy(16.6%). Splints were fabricated in maximum habitual intercuspation or centric re-lation depending on individual patient (54.8%). The hard stabilization form was themost common type of appliance used (35.0%). Moreover, 73.8% of the GDPs didnot employ semi-adjustable articulators, and 69.5% adjusted the appliances at thetime of fixing. The duration of splint use and the frequency of follow-up were con-sidered patient dependent by 62.1% and 72.8%, respectively. GDPs considered thetwo major TMD etiologic categories as multifactorial (20.8%) and occlusion (19.9%).Multidisciplinary medical and dental treatment was considered necessary by 97.9%.Conclusions: The evaluated general dental practitioners manage TMD patients ac-cording to international guidelines.

Description of a rat palatal acrylic plate that can be relined

Purpose: The objective of this article is to describe a method to construct an intraoralacrylic device that permits a reline material to be added to the inner surface of thepalatal plate.Materials and Methods: Fifteen 60-day-old adult female rats (Rattus NorvegicusAlbinus Wistar), weighing 150 to 250 g were used for this study and allocated to threegroups (n = 5): G1, animals wearing a heat-polymerized acrylic resin palatal plate(Lucitone 550) for 14 days; G2, animals wearing a heat-polymerized acrylic resinpalatal plate (Lucitone 550) relined with Tokuyama Rebase II for 14 days; and G3,animals maintained under the same conditions as the experimental groups, withoutwearing palatal plates for 14 days. The manipulation of the animals followed theguidelines of the Brazilian College of Animal Experimentation, under the approval ofthe animal ethics committee of the State University of Ponta Grossa. The palatal platescovered the whole palate, were fixed in the molar region with light-cured resin, andwere kept there for 14 days. The animals received a paste diet and water ad libitum.Before and after the trial period, the rats were weighed individually on a precisionscale. Statistical analysis was performed using a two-way analysis of variance (α =0.05) test for comparison of the animals’ weight (g) at time 0 and after 14 days ofusing the palatal plate.Results: No statistical differences were observed regarding the weight of the animalsamong the experimental groups in the study.Conclusions: The individual master impressions, the molar teeth coverage, and themethod of cementation with nonadhesive composite resin provided good stability forthe palatal plate showed in this study, not disturbing the eating habits and nutritionof the animals. This model seems reproducible, offering adequate histopathologicalevaluation. Differences in tissue morphology exist between the animals that used thepalatal plate and the animals that did not use this device. Use of these palatal platescould clarify how prostheses bring changes in the palatal mucosa of users.

Gel against denture stomatitis: clinical report

The objective of this study is to report the clinical use of 2% Uncaria tomentosa gel against denture stomatitis (DS) as an alternative treatment. The patient was a 65-year-old, denture-wearing woman. At the clinical examination, her palate showed hyperplasic and erythematous mucosa indicating DS type II. DS is a chronic oral disease that affects denture wearers. It occurs as an inflammatory reaction in denture-wearing patients under maxillary prostheses. Candida albicans has been reported as the principal etiological agent. An alternative treatment, the topical application of a gel of 2% U. tomentosa three times a day for 1 week was given to the patient. After 1 week of this treatment, she had significantly reduced signs of the disease. Despite the existence of a great number of antifungal agents, treatment failure is observed frequently. Phytotherapy is becoming more popular worldwide. Currently, the most promising medicinal Amazonian herb is U. tomentosa (Willd.) DC., known as Cat's Claw. Studies of the chemical and pharmacological properties of this medicinal plant have allowed researchers to develop indications for its use. This report demonstrates the effectiveness of U. tomentosa against DS.