Evaluation of Different Polymerisation Methods of Ocular Prosthesis Acrylic Resins on Subcutaneous Tissue Inflammatory Response in Rats.

Objectives: This study aimed to evaluate the influence of different polymerisation methods of acrylic resin for ocular prostheses on the subcutaneous tissue inflammatory response of rats. Methods: The study was conducted at the Basic Sciences Department, Araçatuba Dental School, São Paulo State University (UNESP), Brazil, from 2016 to 2018. The samples were prepared by water bath (WB), microwave energy (MW) or autopolymerisation (AP) (n = 20 samples per group). The inflammatory response (cell count and immunohistochemical analysis of interleukin [IL]-1ß, IL-6, tumour necrosis factor [TNF]-α, IL-17 and macrophage inflammatory protein-3α) was analysed by the implantation of a sample from each group in the subcutaneous tissue of 20 Wistar rats and evaluated after seven, 15, 30 and 60 days. The quantitative and qualitative data were analysed using analysis of variance and Tukey tests (P <0.05) and visual comparison, respectively. Results: There was a moderate inflammatory infiltrate for the MW and AP groups and a light infiltrate for the WB group after seven days. The inflammatory infiltrate and the immunolabeling of tested targets decreased gradually during the 60-day period. The AP group had the highest immunolabeling of TNF-α (seven days), IL-1ß and IL-17 (at 15 and 30 days) and IL-6 (at 30 and 60 days). The WB and MW groups showed greater immunolabeling at 15 and 30 days, while the MW group also had high results at 60 days. Conclusion: Polymerisation by microwave energy and by chemical activation resulted in a higher inflammatory response.

Long-term stainability of interim prosthetic materials in acidic/staining solutions.

OBJECTIVE: To evaluate the long-term color stainability, translucency, and contrast ratio (CR) of different resins used to fabricate interim prostheses after immersion in acidic/staining solutions. MATERIALS AND METHODS: A total of 160 specimens were divided into 16 groups (n = 10) according to the material (heat-polymerized acrylic resin [HPAR], auto-polymerized acrylic resin [APR], nanoparticulated bis-acrylic resin [BR], and prefabricated poly(methyl methacrylate) block for CAD/CAM [CADR]) and immersion solutions (artificial saliva, cola beverage, coffee, and red wine). A spectrophotometer was used before and after each immersion period (7, 14, 28, 90, and 180 days). Color differences (CIEDE2000 and CIELab) were calculated. A three-way repeated-measures analysis of variance and Bonferroni test (α = .05) were used. RESULTS: After 180 days, the APR presented the highest value for coffee and the CADR presented the smallest value for the cola (P < .001). For the CR, the highest values were obtained at 180 days for BR in coffee (1.35) and wine (1.18) (P < .001). Higher translucency parameters were obtained in the BR and CADR in the initial, 14, 28, and 90 days (P < .001). CONCLUSIONS: From the greatest to the smallest staining potential, the solutions were classified as: wine > coffee > cola beverage > saliva, while for the materials as: APR > BR > HPAR > CADR. CLINICAL SIGNIFICANCE: The knowledge of the long-term optical behavior of interim prosthetic materials is important for clinicians to decide which material to use to match the dietary intake of their patients and their esthetic demands. Prefabricated blocks for CAD/CAM systems have been shown to maintaining their optical characteristics even after a long period of immersion in acidic/staining solutions.

Characterisation of a new plasma-enhanced film to improve shear bond strength between zirconia and veneering ceramic.

The aim of this study was to develop and characterise a new plasma-enhanced chemical vapor deposition (PECVD) film for improving shear bond strength (SBS) between yttria-stabilised tetragonal zirconia (Y-TZP) and veneering ceramic. In total, 192 Y-TZP samples (13 × 5.4 × 5 mm) were divided into 6 groups: control - no treatment (C), airborne-particle abrasion with 27 µm aluminum oxide particles (Al27), 110 µm aluminum oxide particles (Al110), and 250 µm aluminum oxide particles (Al250), application of liner for zirconia (L) and the PECVD film application (P). The Y-TZP surface was characterised by means of Scanning Electronic Microscopy (SEM), Energy-dispersive Spectroscopy (EDS), atomic force microscopy (AFM), surface profilometry and surface-free energy (SFE). SBS between Y-TZP and veneering ceramic was tested before and after thermocycling (20,000 cycles of 5 and 55 °C), and failure mode was also evaluated. Data were analysed by ANOVA and Tukey's HSD test (α = 0.05). Data analysis showed that PECVD film had no effect on surface roughness of Y-TZP (p > 0.05 vs control), whilst the other groups presented higher roughness values (p < 0.05). All treatments increased SFE, except the Al27 group. The highest SBS was presented by the P group (p < 0.05), and values were similar to those of the Al27 group (p = 0.107). Mixed failures were prevalent in all groups, and premature failures were found only in Al groups after thermocycling. Whilst PECVD treatment did not affect Y-TZP surface roughness, high SBS between Y-TZP and the veneering layer was observed. Therefore, PECVD treatment is a promising alternative to improve the performance of bi-layer zirconia-based restorations.

Effects of mouth rehabilitation with removable complete dentures on stimulus perception and the electromyographic activity of the orbicularis oris muscle.

STATEMENT OF PROBLEM: Many elderly individuals are rehabilitated with removable complete dentures, which require an initial adaptation period for both oral perception and the perioral muscles. Studies assessing the changes in stimulus perception and the electromyographic (EMG) activity of the orbicularis oris muscle shortly after conventional complete denture insertion are lacking. PURPOSE: The purpose of this clinical study was to evaluate the effect of mouth rehabilitation with removable complete dentures on stimulus perception and the EMG activity of the orbicularis oris muscle. MATERIAL AND METHODS: This study was approved by the Human Research Ethics Committee of the Araçatuba Dental School (São Paulo State University). Fifteen participants who had worn their removable complete dentures for at least 5 years and needed rehabilitation with new prostheses were enrolled in the study. A perception questionnaire was applied, and surface EMG examinations of the orbicularis oris muscle during rest, suction of water with a straw, and pronunciation of the syllables /bah/, /mah/, /pah/, and the word 'Mississippi' were performed before (T0) and 30 (T1) and 100 (T2) days after insertion of the new prostheses. The data were analyzed with the Cochran Q test, McNemar test, 2-way repeated measures ANOVA, and honestly significant difference (HSD) Tukey test (α=.05). RESULTS: Significant improvement was reported in the perception questionnaire in terms of the oral discomfort sensation in the T2 period. EMG activity decreased during rest and suction after insertion of the new prostheses. A statistical difference between the upper and lower fascicles of the orbicularis oris muscle was detected, with a decrease of EMG activity between the T0 and T1 periods on the lower fascicle, except for when pronouncing the /pah/ syllable. CONCLUSIONS: Mouth rehabilitation with removable complete dentures decreased oral discomfort and, depending on the oral function, decreased or increased EMG activity of the orbicularis oris muscle. In addition, the lower fascicle was more active than the upper fascicle during rest and most functional activities.

Influence of adding nanoparticles on the hardness, tear strength, and permanent deformation of facial silicone subjected to accelerated aging.

STATEMENT OF PROBLEM: The efficiency of adding nanoparticles to silicone protection has proven to prevent color degradation. However, reports of other physical property changes in facial silicone are scarce. PURPOSE: The purpose of this in vitro study was to evaluate the influence of adding nanoparticles on the hardness, tear strength, and permanent deformation of a facial silicone. MATERIAL AND METHODS: Specimens were made for each test, with 140 for the hardness test, 140 for the permanent deformation test, but 280 for the rupture test. This higher number was due to the fact that the first 140 specimens were ruptured and unusable after the initial reading. ZnO, BaSO4, and TiO2 nanoparticles at concentrations of 1% and 2% of silicone were used, as well as specimens without nanoparticles that consisted of only oil paint and of only silicone. Outcomes were measured before and after 1008 hours of accelerated aging. Data were analyzed by nested analysis of variance (ANOVA) and Tukey honest significant differences test (α=.05). RESULTS: Results showed that the presence of nanoparticles influenced the properties of the assessed groups. The nanoparticles decreased hardness values. The highest values of tear strength were observed for the groups with addition of BaSO4. The 1% ZnO group without oil paint showed the lowest values of permanent deformation. CONCLUSIONS: Based on the findings of this in vitro study, the use of ZnO nanoparticles is recommended, since they did not negatively affect the properties of the materials evaluated.

Acrylic Resin Cytotoxicity for Denture Base--Literature Review.

Acrylic resin is a widely used material in clinical practice, and a satisfactory biocompatibility is essential. When the resin polymerization reaction is incomplete, residual monomers are released into the oral cavity. The aim of this study was to evaluate, through a literature review, the cytotoxicity caused by the denture base acrylic resin used, and its components. The selection of published studies was performed on the Pubmed database from January 2008 to July 2013. The keywords used were: "cytotoxicity and acrylic resins", "cytotoxicity and denture base resins" and "cytotoxicity and oral prosthesis". Inclusion criteria were: in vitro studies and literature reviews published in English that evaluated the acrylic resin cytotoxicity for denture base and its components. Studies with no reference to the search strategy were excluded. A total of 182 articles were found. Among these, only 13 were included for writing this review. The MTT test is the most common test used to evaluate acrylic resin cytotoxicity. Auto-polymerized resin is more cytotoxic than heat-polymerized resin because of its higher quantity of residual monomers which cause cell and tissue changes in the oral mucosa. However, more studies are necessary for the development of biocompatible materials.

Posterior partially edentulous jaws, planning a rehabilitation with dental implants.

AIM: To discuss important characteristics of the use of dental implants in posterior quadrants and the rehabilitation planning. METHODS: An electronic search of English articles was conducted on MEDLINE (PubMed) from 1990 up to the period of March 2014. The key terms were dental implants and posterior jaws, dental implants/treatment planning and posterior maxilla, and dental implants/treatment planning and posterior mandible. No exclusion criteria were used for the initial search. Clinical trials, randomized and non randomized studies, classical and comparative studies, multicenter studies, in vitro and in vivo studies, case reports, longitudinal studies and reviews of the literature were included in this review. RESULTS: One hundred and fifty-two articles met the inclusion criteria of treatment planning of dental implants in posterior jaw and were read in their entirety. The selected articles were categorized with respect to their context on space for restoration, anatomic considerations (bone quantity and density), radiographic techniques, implant selection (number, position, diameter and surface), tilted and pterygoid implants, short implants, occlusal considerations, and success rates of implants placed in the posterior region. The results derived from the review process were described under several different topic headings to give readers a clear overview of the literature. In general, it was observed that the use of dental implants in posterior region requires a careful treatment plan. It is important that the practitioner has knowledge about the theme to evaluate the treatment parameters. CONCLUSION: The use of implants to restore the posterior arch presents many challenges and requires a detailed treatment planning.

Phantom eye syndrome: a review of the literature.

The purpose of this literature review was to describe the main features of phantom eye syndrome in relation to their possible causes, symptoms, treatments, and influence of eye amputation on quality of life of anophthalmic patients. For this, a bibliographical research was performed in Pubmed database using the following terms: "eye amputation," "eye trauma," "phantom eye syndrome," "phantom pain," and "quality of life," associated or not. Thirteen studies were selected, besides some relevant references contained in the selected manuscripts and other studies hallowed in the literature. Thus, 56 articles were included in this review. The phantom eye syndrome is defined as any sensation reported by the patient with anophthalmia, originated anophthalmic cavity. In phantom eye syndrome, at least one of these three symptoms has to be present: phantom vision, phantom pain, and phantom sensations. This syndrome has a direct influence on the quality of life of the patients, and psychological support is recommended before and after the amputation of the eyeball as well as aid in the treatment of the syndrome. Therefore, it is suggested that, for more effective treatment of phantom eye syndrome, drug therapy should be associated with psychological approach.

Effect of different disinfectants on the microhardness and roughness of acrylic resins for ocular prosthesis.

BACKGROUND: Ocular prosthesis materials should have specific properties for their indication and durability; therefore, it is important to investigate their physical behaviour when affected by several disinfectants. OBJECTIVES: This study evaluated the influence of different disinfecting solutions on the microhardness and surface roughness of acrylic resins for ocular prosthesis. MATERIALS AND METHODS: Fifty samples simulating ocular prostheses were fabricated with N1 resin and colourless resin and divided (n = 10) according to the disinfectant used: neutral soap, Opti-free, Efferdent, 1% hypochlorite (HYC) and 4% chlorhexidine (CHX). Samples were stored in saline solution at 37°C and disinfected during 120 days. Both microhardness and roughness were investigated before, after 60 days and 120 days of disinfection and storage. Microhardness was measured using a microhardner and the roughness with a roughness device. RESULTS: N1 resin showed lower microhardness when compared with colourless resin (p < 0.05). HYC and CHX groups exhibited the highest change of microhardness and roughness values (p < 0.05). An increase in roughness and reduction in microhardness of ocular acrylic resins were observed after both periods of disinfection and storage (p < 0.05). CONCLUSION: Both disinfection/storage periods affected the microhardness and roughness values of the samples.

Effect of thermal cycling and disinfection on colour stability of denture base acrylic resin.

OBJECTIVES: The purpose of this study was to investigate the effect of thermal cycling and disinfection on the colour change of denture base acrylic resin. MATERIALS AND METHODS: Four different brands of acrylic resins were evaluated (Onda Cryl, QC 20, Classico and Lucitone). All brands were divided into four groups (n = 7) determined according to the disinfection procedure (microwave, Efferdent, 4% chlorhexidine or 1% hypochlorite). The treatments were conducted three times a week for 60 days. All specimens were thermal cycled between 5 and 55°C with 30-s dwell times for 1000 cycles before and after disinfection. The specimens' colour was measured with a spectrophotometer using the CIE L*a*b* system. The evaluations were conducted at baseline (B), after first thermal cycling (T1 ), after disinfection (D) and after second thermal cycling (T2 ). Colour differences (ΔE) were calculated between T1 and B (T1 B), D and B (DB), and T2 and B (T2 B) time-points. RESULTS: The samples submitted to disinfection by microwave and Efferdent exhibited the highest values of colour change. There were significant differences on colour change between the time-points, except for the Lucitone acrylic resin. CONCLUSIONS: The thermal cycling and disinfection procedures significantly affected the colour stability of the samples. However, all values obtained for the acrylic resins are within acceptable clinical parameters.

Hyperbaric oxygen therapy treatment for the fixation of implant prosthesis in oncology patients irradiated.

OBJECTIVES: This study aimed to present a clinical report of an irradiated oncologic patient who underwent hyperbaric oxygen therapy to be rehabilitated with implant-supported prosthesis. MATERIALS AND METHODS: A 67-year-old man was admitted at Oral Oncology Center (FOA-UNESP) presenting a lesion on the mouth floor. After clinical evaluation, incisional biopsy and histopathological exam, a grade II squamous cell carcinoma was diagnosed. The patient was subjected to surgery to remove the lesion and partial glossectomy. Afterwards, the radiotherapy, in the left/right cervicofacial area of the supraclavicular fossa, was conducted. After 3 years of the surgery, the patient was submitted to hyperbaric oxygen therapy. Then, four implants were installed in patient's mandible. Five months later, an upper conventional complete denture and lower full-arch implant-supported prosthesis were fabricated. CONCLUSION: The treatment resulted in several benefits such as improving his chewing efficiency, swallowing and speech, less denture trauma on the mucosa and improving his self-esteem.

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.

Unusual presentation of oral squamous cell carcinoma in a young woman.

Oral squamous cell carcinoma (OSCC) is the most common oral malignant neoplasm, mainly affecting individuals over 50 years old with a history of tobacco and alcohol use. The occurrence of this oral cancer in individuals under 40 years old is unusual and, when it does occur, shows a weaker relation to those risk factors and a more aggressive clinical course. Due to the paucity of reports in this population, it is difficult to prove its increasing trend. A case of oral squamous cell carcinoma in a 39-year-old woman with no history of tobacco or alcohol use is reported. Clinical and histopathological findings, aetiology, and treatment are discussed. The increasing trend of oral squamous cell carcinoma in young women without known risk factors highlights the need for clinicians to be prepared to diagnose this lesion quickly and precisely, providing a better prognosis, chance of survival, and quality of life for the patient.

A combination of clinical and microbiological management of generalized aggressive periodontitis in primary teeth. A case report.

BACKGROUND: Generalized aggressive periodontitis (GAP) in primary teeth is a rare periodontal disease that occurs during or soon after eruption of the primary teeth. An association with systemic diseases is a possibility. CASE REPORT: A 4-year-old Brazilian girl presented with GAP involving the entire primary dentition. The patient and her parents and sister were subjected to microbiological testing to identify the microorganisms involved in the disease. The patient underwent tooth extraction to eradicate the disease and received a prosthesis for the restoration of masticatory function. After the permanent teeth erupted, fixed orthodontic appliances were place to restore dental arch form and occlusion. CONCLUSIONS: The results show the importance of an early diagnosis of GAP and of a multidisciplinary approach involving laboratory and clinical management to treat the disease and to restore masticatory function, providing a better quality of life for patients.

Effect of disinfection and storage on the flexural strength of ocular prosthetic acrylic resins.

OBJECTIVE: To evaluate the influence of chemical disinfection and storage duration on the flexural strength of acrylic resins commonly used to make ocular prostheses. METHODS: A total of 260 samples were manufactured with N1 resin and colourless resin. Both resins were thermopolymerised using a microwave oven. Samples were stored and periodically disinfected and were divided into groups: control (no disinfection) (I), neutral soap (II), Opti-free (III), Efferdent (IV), 1% hypochlorite (V) or 4% chlorhexidine (VI). The flexural strength was measured before and after 60 and 120 days of storage. Data were analysed by anova and Tukey test (0.05). RESULTS: The flexural strength of the N1 resin was higher than that for the colourless resin. There was a significant difference in the flexural strength before and after 60 and 120 days of storage with disinfection, regardless of the resin and disinfectant. Group I in the initial period exhibited greater flexural strength, with significant difference only in group VI after 120 days. CONCLUSION: It can be concluded that the flexural strength only changed after 120 days of storage for samples disinfected with chlorhexidine. However, all flexural strength values obtained herein were acceptable clinical limits for the acrylic resins.

Influence of opacifiers on dimensional stability and detail reproduction of maxillofacial silicone elastomer.

BACKGROUND: We evaluated the influence of chemical disinfection and accelerated aging on the dimensional stability and detail reproduction of a silicone elastomer containing one of two opacifiers. METHODS: A total of 90 samples were fabricated from Silastic MDX 4-4210 silicone and divided into groups (n = 10) according to opacifier content (barium sulfate or titanium dioxide) and disinfectant solution (neutral soap, Efferdent, or 4% chlorhexidine). The specimens were disinfected 3 times per week during 60 days and then subjected to accelerated aging for 1008 hours. Dimensional stability and detail reproduction tests were performed after specimens' fabrication (baseline), chemical disinfection and periodically during accelerated aging (252, 504, and 1008 hours). The results were analyzed using 3-way repeated-measures ANOVA and the Tukey HSD test (α = 0.05). RESULTS: All groups exhibited dimensional changes over time. The opacifier (p = .314), period (p < .0001) and their interactions (p = .0041) affected the dimensional stability of the silicone. Statistical significant dimensional differences occurred between groups with (0.071) and without opacifiers (0.053). Accelerated aging influenced the dimensional stability of the samples. All groups scored 2 in the detail reproduction tests, which represents the fully reproducing of three test grooves with accurate angles. CONCLUSIONS: Incorporation of opacifiers alters the dimensional stability of silicones used in facial prosthetics, but seems to have no influence on detail reproduction. Accelerated aging is responsible for most of the dimensional changes in Silastic MDX4 4210, but all dimensional changes measured in this study remained within the limits of stability necessary for this application.