Effect of polymerization method and fabrication method on occlusal vertical dimension and occlusal contacts of complete-arch prosthesis.

Purpose: This study evaluated the dimensional stability of a complete-arch prosthesis processed by conventional method in water bath or microwave energy and polymerized by two different curing cycles.

Materials And Methods: Forty maxillary complete-arch prostheses were randomly divided into four groups (n = 10): MW1 - acrylic resin cured by one microwave cycle; MW2 - acrylic resin cured by two microwave cycles: WB1 - conventional acrylic resin polymerized using one curing cycle in a water bath; WB2 - conventional acrylic resin polymerized using two curing cycles in a water bath. For evaluation of dimensional stability, occlusal vertical dimension (OVD) and area of contact points were measured in two different measurement times: before and after the polymerization method.

Fluorination of zirconia surfaces impairs bonding to resin cement.

The aim of this study was to evaluate the fluorination of a zirconia surface as an alternative treatment for bonding to resin cement; the null hypothesis was that fluorination would not improve adhesion values. Four different surface treatments were performed on the surface of yttria-stabilized tetragonal zirconia polycrystal discs (N = 80): Ctrl (control), no treatment; SB, sandblasting with 50-μm alumina particles; SBS, sandblasting with 30-μm silica-modified alumina particles and application of silane; and SF, fluorination with sulfur hexafluoride-containing plasma. The surface roughness (Ra) of each group was measured after surface treatment.

Three-dimensional finite element analysis of occlusal splint and implant connection on stress distribution in implant-supported fixed dental prosthesis and peri-implantal bone.

The aim of this study was to investigate the influence of occlusal splint therapy on the stress distribution of implant-supported fixed dental prosthesis (FDP) and peri-implantal bone structures using three-dimensional (3D) finite element analysis (FEA). The system consisted of two implants (positioned on region of second premolar and second molar) as retainers of fixed porcelain-fused-to-metal 3-unit FDP (first molar as pontic element). Two implant connections systems (external and internal hexagon) were tested.

Effect of interim cement application on bond strength between resin cements and dentin: Immediate and delayed dentin sealing.

Statement Of Problem: Despite the advances in materials and techniques, adhesion to dentin is challenging because of the complex composition of dentin's mineral, organic, and fluid phases.

Purpose: The purpose of this in vitro study was to evaluate the bond strength of 2 different resin cements (conventional and self-adhesive) with or without previous dentin sealing and the effect of interim cement.

Material And Methods: Forty-five molars were embedded into acrylic resin blocks and a flat dentin surface was exposed.

Influence of abutment design on retention of metal copings cemented to implants.

The study evaluated the influence of abutment design on the retention of implant-cemented metal copings. Two abutments of the same system with the same indications, height and the total occlusal convergence, but of different designs were evaluated. Ten RN synOcta abutments (Straumann, Waltham, MA) and ten RN titanium solid abutments (Straumann, Waltham, MA) were tightened to 35 Ncm on 20 implant analogs previously placed in resin blocks.

Thickness and marking quality of different occlusal contact registration strips.

Objectives: Evaluate the thickness and the marking quality of different occlusal contact registration strips (OCRS) and a possible correlation between them.

Material And Methods: The following OCRS were selected: Accufilm II, BK20, BK21, BK22, BK23, BK28, and BK31. The thickness was measured in three points of the OCRS with an electronic measuring device (TESA), and the mean was calculated.

Mechanical properties of direct and indirect composites after storage for 24 hours and 10 months.

Objective: The objective of this study was to evaluate the diametral tensile strength (DTS) and Knoop hardness (KH) of direct (Filtek Z350-3M/ESPE and Charisma-Heraeus Kulzer) and indirect composites (Sinfony-3M/ESPE and Signum-Heraeus Kulzer) kept in storage for two periods of time, 24 hours and 10 months, in distilled water.

Methods: Twenty-five specimens of each material were prepared. DTS (n=10) was tested using a universal testing machine (Versat, model 2000) at a crosshead speed of 1.

Influence of disinfection with peracetic acid and hypochlorite in dimensional alterations of casts obtained from addition silicone and polyether impressions.

Dental impressions disinfection is important to reduce the risk of cross contamination but this process may produce dimensional distortions. Peracetic acid is a disinfectant agent with several favorable characteristics yet underutilized in Dentistry. The aim of this paper is to compare the dimensional stability of casts obtained from addition silicone and polyether impressions that were immersed for 10 minutes in a solution of 0.

Influence of diamondlike carbon-coated screws on the implant-abutment interface.

Purpose: To evaluate the implant-abutment interface area and the abutment screw loosening value when diamondlike carbon (DLC)-coated or titanium screws were used before and after cyclic loading.

Materials And Methods: Thirty-six implants were divided into four groups according to the type of connection (external hexagon [EH] or internal hexagon [IH]) and the type of abutment screw (with [EHD/IHD] or without [EHT/IHT] DLC coating). The implants were placed in epoxy resin-glass fiber composite, and crowns cast in a metal alloy were screwed to the implants.

Influence of loading and use of occlusal splint in implant-supported fixed prostheses.

The aim of the study was to assess the tensions generated in the long axis of the implants and the interimplants in the cervical, middle, and apical regions when subjected to different loads with or without interposition of the flat occlusal plane splint. A photoelastic model was made with 2 external hexagon implants located in the space corresponding to the second premolar and molar inferiors. A screw-retained metal superstructure was installed on the implants with a torque of 20 N·cm, and the set (photoelastic model with superstructure) were positioned in the circular polariscope in the dark-field configuration to observe the distribution of isochromatic fringes around the implants and interimplant areas.

Influence of photoactivation method and mold for restoration on the Knoop hardness of resin composite restorations.

The aim of this study was to evaluate in vitro the Knoop hardness in the top and bottom of composite photo activated by different methods when different mold materials were used. Z250 (3M ESPE) and XL2500 halogen unit (3M ESPE) were used. For hardness test, conical restorations were made in extracted bovine incisors (tooth mold) and also metal mold (approximately 2 mm top diameter × 1.

Influence of different materials and techniques to transfer molding in multiple implants.

The aim of this study was to compare different materials and techniques used in transfer molding of multiple implants, by evaluating the space between implants and superstructure. Four external hexagon implants were fixed in a master template and the same on a superstructure. Transfer molding of implants were done using the direct and indirect techniques, with transfers united or not, using the union chemically activated acrylic resin (QA) and other groups polymerized acrylic resin (FT), and sectioned and not split.

Influence of re-using reversible hydrocolloids on the linear alteration of coating models.

Reusing reversible hydrocolloids too many times may cause alterations of the coating model and produce unsatisfactory RPPs. The aim of this study was to analyze the linear alterations of coating models reproduced from molds obtained with two commercial brands of reversible hydrocolloid (RH) with 15 reuse cycles of the material. A metal model was used with 4 marks (A, B, C and D) on which the distances AB, BC, CD, DA, BD and AC could be measured lineally.

Root surface treatment using diode laser in delayed tooth replantation: radiographic and histomorphometric analyses in rats.

Unlabelled: BACKGROUND AIM:  The aim of this study was to evaluate, by radiographic and histomorphometric analyses, the effects of high-power diode laser irradiation on the root surfaces of delayed replanted rat teeth.

Material And Methods:   Maxillary right incisors were extracted from 60 Wistar rats and kept dry for 60 min. Subsequently, the root canals were prepared and filled with calcium hydroxide paste.

Influence of different flasking and polymerizing methods on the occlusal vertical dimension of complete dentures.

The flasking and polymerization technique for resins can introduce stresses during processing which may lead to denture base distortions, artificial teeth displacement and increases in the occlusal vertical dimension (OVD). This study investigated whether the association of microwave heat-activation (MH) and bimaxillary flasking (BF) minimizes the possible increases in OVD after prostheses processing. Forty pairs of complete dentures were waxed with the artificial teeth in closed occlusion and divided into four groups according to investing and heating methods: G1 (control) = monomaxillary/water bath; G2 = monomaxillary/microwave; G3 = bimaxillary/water bath and G4 = bimaxillary/microwave.

Oral granuloma formation after injection of cosmetic filler.

The increased use of orofacial fillers in cosmetic procedures has led to new diagnostic challenges for dentists and oral pathologists. Here, we describe a case with multiple oral foreign body granulomas, which were formed after a polymethylmetacrylate injection for cosmetic purposes.

Evaluation of the accuracy of different transfer impression techniques for multiple implants.

The aim of this study was to evaluate the accuracy of three implant transfer impression techniques. Four groups (n = 5) were defined, according to the technique: TC - tapered copings without splint; SC - square copings without splint; SCS - square copings splinted with dental floss and acrylic resin, and CG (control group) - master model with four external hexagonal implants and a superstructure. Individual trays and polyether were used for the impression.

Attachment of cultured fibroblasts and ultrastructural analysis of simulated cervical resorptions treated with high-power lasers and MTA.

Objective: The present study evaluated the fibroblast attachment and the morphologic changes of simulated cervical root resorptions after irradiation with high-power lasers and the use of mineral trioxide aggregate (MTA).

Study Design: Standardized cavities were done on the coronal third of 40 single-rooted teeth and assigned into 4 groups according to the treatment applied: (1) untreated control, (2) use of MTA, (3) irradiation with Er:YAG laser (42 mJ, 10 Hz, 10 s), and (4) irradiation with high-power diode laser (1 W, 10 s). Fragments were prepared for SEM analysis: 6 samples of each group were plated with human gingival fibroblasts and 4 samples were used for ultrastructural analysis.

Influence of anatomic reference on the buccal contour of prosthetic crowns.

During clinical practice, when performing prosthetic rehabilitation with single crowns, improper reproduction of the dental contour by the dental laboratory is a common occurrence. Therefore, the present study evaluated the fidelity of the reproduction of the buccal contour in an upper left canine performed by three Dental Prosthesis Technicians (DPT) using the indirect laminate veneer technique. First, the DPTs confected the veneers based on a model obtained from the upper arch of a dental dummy, containing a replica of an upper left canine with a prosthetic preparation for a laminate veneer.

Concurrence between interpupillary line and tangent to the incisal edge of the upper central incisor teeth.

Objective: Dento-facial harmony is essential to obtain adequate esthetics and a successful treatment. Therefore, the aim of the present study was to analyze the existence of polar symmetry, obtained by two parallel lines, one along the pupils and another along the incisal edge of the upper central incisor teeth of 102 dental students distributed across five Brazilian dental schools.

Materials And Methods: One hundred and two students with no missing teeth, who had never been subjected to any kind of dental treatment, not even orthodontic treatment, were selected and photographed using a dental eye II camera (Yashica-Kyocera Optics Inc.

Degree of conversion and contraction stress development of a resin composite irradiated using halogen and LED at two C-factor levels.

This study verified the influence of curing methods and light sources on contraction stress, stress rate and degree of conversion (DC) of a restorative composite at two C-factor (CF) levels. For the stress test, composite (0.84 mm thick) was applied between two glass rods 5-mm in diameter mounted in a servohydraulic testing machine.

Vinegar as an antimicrobial agent for control of Candida spp. in complete denture wearers.

The use of denture is known to increase the carriage of Candida in healthy patients, and the proliferation of Candida albicans strains can be associated with denture-induced stomatitis. The aim of this study was to evaluate the use of vinegar as an antimicrobial agent for control of Candida spp. in complete upper denture wearers.

Palpation and pressure pain threshold: reliability and validity in patients with temporomandibular disorders.

This study assessed the interexaminer reliability and validity of palpation (PA) and pressure pain threshold (PPT) of the temporomandibular joint (TMJ) and the masseter and temporalis muscles in patients with temporomandibular disorders (TMD) and asymptomatic controls. Eighty (80) subjects were distributed into two groups: Group 1 consisted of 40 TMD patients with muscular and joint pain selected by RDC/TMD Axis I; and Group 2 (control) with 40 asymptomatic individuals. Training and calibration of examiners was undertaken prior to testing.

Traumatic fractures of the tympanic plate: a literature review and case report.

Fracture of the tympanic plate resulting from posterior dislocation of the mandibular condyle is an uncommon diagnosis. Presented is a clinical case in which computerized tomography was used as a diagnostic resource in a conservative therapeutic and clinical controlled one-year study. A review of the literature revealed 23 cases clinically reported with symptoms, diagnosis, and types of therapy utilized.

Evaluation of the etiology of ocular globe atrophy or loss.

This survey investigated the etiology of atrophy or loss of the ocular globe in patients assisted at the Maxillofacial Prosthetics Clinic of two Schools of Dentistry in São Paulo State, Brazil. A total of 238 patients were examined and their clinical files were reviewed. The etiology of eyeball atrophy/loss was assessed with respect to gender, age group, affected side and type ophthalmologic surgery performed.