Investigation of the effects of arch size and implant angulation on the accuracy of digital impression using two intraoral scanners: An in vitro study.

Objectives: The aim of this in vitro study was to evaluate the effect of arch size and implant angulation on the accuracy of digital impression in two intraoral scanners of Trios (3shape) and CEREC (Omnicam).

Material And Methods: Four acrylic models each including six implants at sites 11, 12, 15, 17, 23, and 27 were used, including large with parallel implants, large with angled implants, small with parallel implants, and small with angled implants. After tightening the scan bodies, distance measurements were done using a coordinate measuring machine.

Color Stability of Different Denture Teeth Following Immersion in Staining Solutions.

This study aimed to assess the color change (∆E00) of 7 brands of denture teeth (conventional acrylic and composite teeth) following immersion in staining solutions. Maxillary central incisor denture teeth made of 4 conventional acrylic resins (Vitapan, SR Vivodent PE, Beta Star and Crystal) and 3 composite resins (Finex, Emeral and Phonares II) were randomly divided into four groups (n=5). Denture teeth of different brands were immersed in tea, coffee, cola, and turmeric solutions.

Marginal adaptation of three-unit interim restorations fabricated by the CAD-CA systems and the direct method before and after thermocycling.

Background: Limited information is available regarding the marginal adaptation of three-unit interim restorations fabricated by different techniques from different materials. Also, the efficacy of computer-aided design/computer-aided manufacturing (CAD-CAM) systems for their fabrication is still questionable. This study aimed to assess the marginal adaptation of three-unit interim restorations fabricated by the CAD-CAM systems and the direct method from different materials before and after thermocycling.

Microtensile bond strength of CAD/CAM-fabricated polymer-ceramics to different adhesive resin cements.

Objectives: This study evaluated the microtensile bond strength (µTBS) of polymer-ceramic and indirect composite resin with 3 classes of resin cements.

Materials And Methods: Two computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated polymer-ceramics (Enamic [ENA; Vita] and Lava Ultimate [LAV; 3M ESPE]) and a laboratory indirect composite resin (Gradia [GRA; GC Corp.]) were equally divided into 6 groups ( = 18) with 3 classes of resin cements: Variolink N (VAR; Vivadent), RelyX U200 (RXU; 3M ESPE), and Panavia F2 (PAN; Kuraray).

Effect of Selected Luting Agents on the Retention of CAD/CAM Zirconia Crowns Under Cyclic Environmental Pressure.

Objectives: The aim of this study was to evaluate the retention strength of zirconia crowns luted with two types of resin cement under environmental pressure changes.

Materials And Methods: Thirty zirconia crowns were fabricated by using computer-aided design/computer-aided manufacturing (CAD/CAM) system and were cemented by Panavia F2.0 (PAN), hand-mixed RelyX Unicem (UNH), or auto-mix RelyX Unicem Aplicap (UNA) cements on the corresponding extracted human molars.

Fracture Resistance of Ceramic Laminate Veneers Bonded to Teeth with Class V Composite Fillings after Cyclic Loading.

Purpose: Porcelain laminate veneers (PLVs) are sometimes required to be used for teeth with composite fillings. This study examined the fracture strength of PLVs bonded to the teeth restored with different sizes of class V composite fillings.

Materials And Methods: Thirty-six maxillary central incisors were divided into three groups (=12): intact teeth (control) and teeth with class V composite fillings of one-third or two-thirds of the crown height (small or large group, resp.

Management of Limited Interocclusal Distance with the Aid of a Modified Surgical Guide: A Clinical Report.

In completely edentulous patients, limited interarch distance can compromise conventional prosthetic fabrication. Bone reduction through various surgical procedures has been recommended to restore an acceptable interarch distance. In such circumstances, a surgical guide built on a mounted cast can be used to minimize and control the amount of bone reduction performed.

Comparison of Flexural Strength of Resin Cements After Storing in Different Media and Bleaching Agents.

The aim of this study was to determine the effects of different storage media and bleaching treatments on the flexural strength of two resin cements (Panavia and BisCem). One hundred rectangular-shaped specimens were prepared with two resin cements and were stored in five media types (n = 10): distilled water (DW), lactic acid (LA), sodium hydroxide (NH), in-office bleaching (OB) and home bleaching (HB). There was significant interaction between the solutions and cements (p < 0.

Effect of Resin Cement Mixing Method on the Retention Strength of a CAD/CAM Zirconia Crowns.

Several treatments have been suggested to improve the retention of zirconia-based restorations luted with different cements. Resin cements are believed to improve crown retention under certain circumstances. The aim of the present study was to examine the effect of three cements with different mixing methods on the retention of CAD/CAM zirconia crowns.

Effect of increased crown height on stress distribution in short dental implant components and their surrounding bone: A finite element analysis.

Statement Of Problem: Implants in posterior regions of the jaw require short dental implants with long crown heights, leading to increased crown-to-implant ratios and mechanical stress. This can lead to fracture and screw loosening.

Purpose: The purpose of this study was to investigate the dynamic nature and behavior of prosthetic components and preimplant bone and evaluate the effect of increased crown height space (CHS) and crown-to-implant ratio on stress concentrations under external oblique forces.

Practical guidelines for fabricating mandibular guide flange prostheses: A new technique for measuring the flange angulation.

Background And Aim: When a mandibulectomy causes discontinuity, the patient will need a rehabilitative prosthesis to achieve a proper occlusal relationship.

Technique: This article describes step-by-step guidelines for measuring the patient-specific mandibular guide flange angulation. In the presented technique, the flange angulation is determined by dividing the horizontal overlap of the maxillary posterior teeth plus the maxillary buccal clasp thickness by the vertical distance of the mandibular continuous clasp up to the maxillary buccal clasp.

Dynamic nature of abutment screw retightening: finite element study of the effect of retightening on the settling effect.

Statement Of Problem: A fundamental problem in fully understanding the dynamic nature of screw loosening is lack of recognition of the entire process of screw tightening and retightening.

Purpose: The purpose of this study was to explain the dynamic nature of abutment screw retightening by using finite element methods to investigate the effect of the coefficient of friction and retightening on the settling effect.

Material And Methods: Precise computer models were designed of a Straumann dental implant, a directly attached crown, an abutment screw, and the bone surrounding the implant.

Effect of the coefficient of friction and tightening speed on the preload induced at the dental implant complex with the finite element method.

Statement Of Problem: To prevent screw loosening, a clear understanding of the factors influencing secure preload is necessary.

Purpose: The purpose of this study was to investigate the effect of coefficient of friction and tightening speed on screw tightening based on energy distribution method with exact geometric modeling and finite element analysis.

Material And Methods: To simulate the proper boundary conditions of the screw tightening process, the supporting bone of an implant was considered.

In vitro evaluation of the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with composite fillings after cyclic loading.

Purpose: There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings.

Materials And Methods: Thirty maxillary central incisors were divided into three groups (for each group, n=10): intact teeth (NP), teeth with class III composite fillings (C3) and teeth with class IV cavities (C4).

Effects of impression levels and trays on the accuracy of impressions taken from angulated implants.

Background And Purpose: It is crucial to keep the misfit of the abutment-fixture unit at the lowest possible rate. There are a few controversial studies on the accuracy of impression making of angulated implants, and much fewer (and controversial) studies on the abutment-level impression technique, which is a convenient and clinically favorable method. Besides, there are no studies on comparison of sectional vs.

The effect of thermocycling on tensile bond strength of two soft liners.

Objective: Failure of soft liners depends mostly on separation from the denture base resin; therefore measurement of the bond strength is very important. The purpose of this study was to compare the tensile bond strength of two soft liners (Acropars, Molloplast-B) to denture base resin before and after thermocycling.

Materials And Methods: Twenty specimens fromeach of the two different soft liners were processed according to the manufacturer's instructions between two polymethyl methacrylate (PMMA) sheets.

Microleakage of different post systems and a custom adapted fiber post.

Objective: The effects of closely adapting a prefabricated fiber to the post space remain unknown. The purpose of this study was to quantify the microleakages of a custom adapted fiber-reinforced post, a prefabricated quartz fiber post and a cast post using nondestructive methods.

Materials And Methods: Sixty-five extracted human premolars were endodontically treated and randomly divided into three groups (n=15), which were restored using a cast post-and-core, a custom adapted fiber post (Refropost) with a microhybrid microfiller resin composite (Gradia), or a prefabricated quartz fiber post (DT light post) and two groups of control (n=10).

Verification of the mechanostat theory in mandible remodeling after tooth extraction: animal study and numerical modeling.

Bone tissue is capable of remodeling in response to environmental and physiological conditions. Mechanical loading is thought to be one of the most important environmental factors, affecting bone status. Mechanostat theory, which classifies bone behavior on the basis of the mechanical strain, has been vastly applied in cases of long bones.

Active tactile sensibility of single-tooth implants versus natural dentition: a split-mouth double-blind randomized clinical trial.

Background: Unlike passive sensitivity of implants/teeth that is assessed more, only three controversial studies have compared active tactile sensibility (ATS) of implants and teeth.

Purpose: We aimed to explore the difference between the ATS of teeth and single-tooth implants.

Methods: The ATS of single-tooth implants and contralateral teeth was measured in 25 patients after they bit on gold and placebo foils 0- to 70-μm thick, each for five times, in a random order blinded to patients and assessor, carried out at two sessions.

Using neutral zone concept in prosthodontic treatment of a patient with brain surgery: a clinical report.

The prosthodontic treatment of a patient who had undergone brain surgery to resect a brain stem astrocytoma has been described. Since the motor innervation to the oral muscles was impaired, the new neutral zone was recorded by using a tissue conditioner material. The teeth and polished surfaces of the mandibular partial denture fitted to the functional cheek anatomy of the surrounding tissue helped in the stability of the denture and to avoid the end tongue biting.

Prosthodontic rehabilitation of a bruxer patient with severely worn dentition: a clinical case report.

The management of tooth wear has been a subject of increasing interest from both preventive and restorative points of view. This article describes the full mouth rehabilitation of a 54-year-old bruxer woman with a severely worn dentition and other dental problems including unsuitable restorations and several missing teeth. The treatment entailed using cast posts and cores, metal-ceramic restorations, and a removable partial denture.

Fixed rehabilitation of an ACP PDI class III patient with amelogenesis imperfecta.

This clinical report describes the oral rehabilitation of a 19-year-old woman diagnosed with hypoplastic-type amelogenesis imperfecta (AI). She presented with discolored and mutilated teeth, missing teeth, anterior open bite, and posterior short crowns. She was classified as an American College of Prosthodontists Prosthodontic Diagnostic Index (ACP PDI) class III patient.

Patient satisfaction with implant-retained mandibular overdentures: a retrospective study.

Purpose: The aim of this study was evaluation of the effect of age, gender, and past prosthetic history (duration of edentulism, number of complete dentures before implant treatment, and number of adjustment appointments) on patients' ratings of satisfaction (comfort, hygiene, retention, appearance, speech, mastication, and overall satisfaction).

Materials And Methods: In this retrospective study, 55 patients who were treated with mandibular overdentures retained by splinted implants from 1998 to 2004 and met the inclusion criteria of the study were selected. Each patient was asked to fill out a questionnaire to evaluate his/her general satisfaction with the implant prostheses and other aspects of satisfaction such as comfort, aesthetic, function, and hygiene.