Rotational Load Fatigue Performance of a One-Size Implant- Abutment Connection System.

Purpose: To investigate the rotational load fatigue performance of different implant diameters and abutment platforms of a one-size implant-abutment (OSIA) connection system.

Materials And Methods: Narrow-, regular-, and wide-diameter implants were tested with regular base (RB/WB) abutments of an OSIA system (BLX, Straumann). Wide-diameter implants (WDIs) were also tested with wide base (WB) abutments.

Rotational Load Fatigue Performance of an Implant System with an Internal Conical Connection and Microthreads.

Purpose: This in vitro study investigated the effect of implant geometry and diameter on the rotational load fatigue performance of an implant system with an internal conical connection with microthreads.

Materials And Methods: Regular (4.2 mm) and wide-diameter (4.

Three-dimensional analysis of the interchangeability of a semiadjustable articulator system in service over time.

Statement Of Problem: Some contemporary articulator systems claim to be highly precise in their interchangeability, with tolerances below 10 μm in vertical error; however, the claims have not been independently verified.

Purpose: The purpose of this study was to investigate the interchangeability of calibrated semiadjustable articulators in service over time.

Material And Methods: A calibrated mounting articulator served as the master articulator, while the test groups were used articulators with a minimum of 1-year use by predoctoral dental students (n=10); used articulators with a minimum of 1-year use by prosthodontic residents (n=10); and new articulators (n=10).

Comparison of 3D positional accuracy of implant analogs in printed resin models versus conventional stone casts: Effect of implant angulation.

Purpose: To study the effect of implant angulation on 3D linear and absolute angular distortions of implant analogs in printed resin models and conventional stone casts.

Materials And Methods: Three sectional master models with two implants with total inter-implant angulations of 0°, 10°, and 20° were fabricated. For each master model, five conventional stone casts (CS) and printed resin models (PM) were fabricated (n = 5).

Esthetic Evaluation of Anterior Implant-Supported Single Crowns: A Comparison Between Patients and Dentists.

Purpose: To compare the esthetic outcomes of anterior implant-supported single crowns as evaluated by patients and clinicians of different specialties.

Materials And Methods: A total of 133 patients with 138 implant-supported crowns were recalled from the National Dental Centre Singapore Implant Registry to rate the esthetic outcomes of their restorations using a visual analog scale (VAS) questionnaire. Patients with crowns in the maxillary or mandibular canine-to-canine region with a contralateral natural tooth and minimum time in function of 6 months were recruited.

Rotational Load Fatigue Performance of Titanium vs Titanium-Zirconium Implant-Abutment Connections.

Purpose: Titanium-zirconium (Ti-Zr) alloy has been developed to strengthen the implant body, but clinically relevant information is still limited. The aim of this in vitro study was to compare the rotational load fatigue performance of implant-abutment connections in narrow-diameter (3.3-mm) and regular-diameter (4.

Prevalence and risk factors of erosive tooth wear among young adults in the Singapore military.

Objectives: Erosive tooth wear (ETW) is defined as the irreversible chemo-mechanical loss of dental hard tissues without plaque or bacteria and has been a growing phenomenon in the general population worldwide. The aim of this study was to determine the prevalence of ETW and the associated risk factors among young military personnel in Singapore.

Materials And Methods: This cross-sectional study consisted of a questionnaire and clinical examination of military personnel between 18 and 25 years.

Three-dimensional positional accuracy of intraoral and laboratory implant scan bodies.

Statement Of Problem: In the implant digital workflow, scan bodies provide the 3D position of digital implants in the virtual dental arch. However, limited evidence is available on scan body accuracy, selection, and usage.

Purpose: The purpose of this in vitro study was to evaluate the 3D positional accuracy of 4 intraoral and 6 laboratory scan body systems to the implants and laboratory replicas of an implant system under various torque magnitudes.

Accuracy of Implant Analogs in 3D Printed Resin Models.

Purpose: To study the effect of implant analog system, print orientation, and analog holder radial offset on 3D linear and absolute angular distortions of implant analogs in 3D printed resin models.

Materials And Methods: A sectional master model simulating a 2-implant, 3-unit fixed prosthesis in a partially edentulous jaw was fabricated. Three implant analog systems for 3D printed resin models-Straumann (ST), Core3DCentres (CD) and Medentika (MD)-were tested.

Spectrophotometric and Visual Evaluation of Maxillary Anterior Implant Crowns and Peri-implant Soft Tissues: A Retrospective Study.

Purpose: To visually and spectrophotometrically determine the differences in the shades of maxillary anterior implant crowns and peri-implant soft tissues compared to a natural teeth control group.

Materials And Methods: A total of 44 patients restored with single implant-supported restorations were assessed after at least 6 months in function. Images of the implant crowns, peri-implant soft tissues, and their controls were captured using a spectrophotometer (SpectroShade Micro, Medical High Technologies).

A Retrospective Study on the Success, Survival, and Incidence of Complications of Post-Retained Restorations in Premolars Supporting Fixed Dental Prostheses with a Mean of 7 Years in Function.

Purpose: To evaluate the survival and success rates of post-and-core restorations supporting fixed dental prostheses (FDPs) after a mean time in function of 7 years and to assess the incidences of biologic and technical complications.

Materials And Methods: Patients from the National Dental Center Singapore (NDCS) with endodontically treated premolars restored with post-retained FDPs from 2007 to 2009 were recruited from the Endodontic Registry and evaluated by three clinicians. A total of 265 patients with 329 treated premolars were examined clinically.

Comparison of Three-Dimensional Accuracy of Digital and Conventional Implant Impressions: Effect of Interimplant Distance in an Edentulous Arch.

Purpose: This study compared the three-dimensional (3D) accuracy of conventional impressions with digital impression systems (intraoral scanners and dental laboratory scanners) for two different interimplant distances in maxillary edentulous arches.

Materials And Methods: Six impression systems comprising one conventional impression material(Impregum), two intraoral scanners (TRIOS and True Definition), and three dental laboratory scanners (Ceramill Map400, inEos X5, and D900) were evaluated on two completely edentulous maxillary arch master models (A and B) with six and eight implants, respectively. Centroid positions at the implant platform level were derived using either physical or virtual probe hits with a coordinate measuring machine.

Associations between symptoms of temporomandibular disorders, quality of life and psychological states in Asian Military Personnel.

Background: Symptoms of Temporomandibular Disorders (TMD) could affect oral health-related quality of life (OHRQoL) and psychological distress.

Objective: This study aims to determine the prevalence of TMD symptoms, and impact of type and number of TMD symptoms on OHRQoL and psychological states among Asian military personnel.

Method: The study was conducted across 12 military dental centres using self-administered questionnaire comprising demographical data, DC/TMD symptom questionnaire, OHIP-14 and DASS-21.

Prevalence of Sleep Bruxism and Its Association with Obstructive Sleep Apnea in Adult Patients: A Retrospective Polysomnographic Investigation.

Aims: To determine the prevalence of sleep bruxism (SB) in adult obstructive sleep apnea (OSA) patients, to assess the association between SB and OSA in terms of sleep macrostructure and respiratory parameters, and to determine possible OSA risk factors for SB.

Methods: Type I polysomnographic data of 147 adult OSA patients (mean age 44.6 ± 12.

Three-Dimensional Static Articulation Accuracy of Virtual Models - Part I: System Trueness and Precision.

Purpose: To evaluate the 3D static articulation accuracy of 3 model scanner-CAD systems (Ceramill Map400 [AG], inEos X5 [SIR], Scanner S600 Arti [ZKN]) using a coordinate measuring machine (CMM). Trueness and precision for each system will be reported in Part I.

Materials And Methods: The master model simulated a single crown opposing a 3-unit fixed dental prosthesis.

Three-Dimensional Static Articulation Accuracy of Virtual Models-Part II: Effect of Model Scanner-CAD Systems and Articulation Method.

Purpose: Accurate maxillomandibular relationship transfer is important for CAD/CAM prostheses. This study compared the 3D-accuracy of virtual model static articulation in three laboratory scanner-CAD systems (Ceramill Map400 [AG], inEos X5 [SIR], Scanner S600 Arti [ZKN]) using two virtual articulation methods: mounted models (MO), interocclusal record (IR).

Materials And Methods: The master model simulated a single crown opposing a 3-unit fixed partial denture.

Three-Dimensional Accuracy of Digital Static Interocclusal Registration by Three Intraoral Scanner Systems.

Purpose: Prior studies have defined the accuracy of intraoral scanner (IOS) systems but the accuracy of the digital static interocclusal registration function of these systems has not been reported. This study compared the three-dimensional (3D) accuracy of the digital static interocclusal registration of 3 IOS systems using the buccal bite scan function.

Materials And Methods: Three IOS systems compared were 3M True Definition Scanner (TDS), TRIOS Color (TRC), and CEREC AC with CEREC Omnicam (CER).

Fabricating CAD/CAM Implant-Retained Mandibular Bar Overdentures: A Clinical and Technical Overview.

This report describes the clinical and technical aspects in the oral rehabilitation of an edentulous patient with knife-edge ridge at the mandibular anterior edentulous region, using implant-retained overdentures. The application of computer-aided design and computer-aided manufacturing (CAD/CAM) in the fabrication of the overdenture framework simplifies the laboratory process of the implant prostheses. The Nobel Procera CAD/CAM System was utilised to produce a lightweight titanium overdenture bar with locator attachments.

Reliability, failure probability, and strength of resin-based materials for CAD/CAM restorations.

Objective:: This study investigated the Weibull parameters and 5% fracture probability of direct, indirect composites, and CAD/CAM composites.

Material And Methods:: Discshaped (12 mm diameter x 1 mm thick) specimens were prepared for a direct composite [Z100 (ZO), 3M-ESPE], an indirect laboratory composite [Ceramage (CM), Shofu], and two CAD/CAM composites [Lava Ultimate (LU), 3M ESPE; Vita Enamic (VE), Vita Zahnfabrik] restorations (n=30 for each group). The specimens were polished, stored in distilled water for 24 hours at 37°C.

Three-dimensional repositioning accuracy of semiadjustable articulator cast mounting systems.

Statement Of Problem: In spite of its importance in prosthesis precision and quality, the 3-dimensional repositioning accuracy of cast mounting systems has not been reported in detail.

Purpose: The purpose of this study was to quantify the 3-dimensional repositioning accuracy of 6 selected cast mounting systems. Five magnetic mounting systems were compared with a conventional screw-on system.

Evaluation of the marginal fit of a zirconia ceramic computer-aided machined (CAM) crown system.

Statement Of Problem: The marginal fit of crowns is a concern for clinicians, and there is no conclusive evidence of any one margin configuration yielding better results than others in terms of marginal fit.

Purpose: The purpose of this study was to evaluate the marginal fit with respect to gap and overhang of Y-TZP (yttria-stabilized tetragonal zirconia polycrystals) ceramic crowns and compare them with lithium disilicate pressable and complete metal crowns. The influence of margin configuration on the marginal fit was also evaluated.

The effect of preparation height and luting agent on the resistance form of cemented cast crowns under load fatigue.

Statement Of Problem: The minimum amount of resistance form required for the success of a clinical crown is unknown.There is little information on the fatigue performance of complete coverage restorations on natural tooth preparations cemented with different luting cements.

Purpose: The purpose of this study was to evaluate the effect of tooth preparation height and luting agent on resistance form using unidirectional load fatigue testing.

Load-fatigue performance of gold crowns luted with resin cements.

Statement Of Problem: Resin cements have gained popularity over the past few years because of their improved physical properties. There is a need to test these cements under fatigue loading, as there is growing recognition that fatigue testing is more clinically relevant than traditional monotonic static tests.

Purpose: This study investigated the load-fatigue performance of complete gold crowns cemented with 4 types of resin cement.

Risk perception and impact of Severe Acute Respiratory Syndrome (SARS) on work and personal lives of healthcare workers in Singapore: what can we learn?

Introduction: Healthcare workers (HCWs) were at the frontline during the battle against Severe Acute Respiratory Syndrome (SARS). Understanding their fears and anxieties may hold lessons for handling future outbreaks, including acts of bioterrorism.

Method: We measured risk perception and impact on personal and work life of 15,025 HCWs from 9 major healthcare institutions during the SARS epidemic in Singapore using a self-administered questionnaire and Impact of Events Scale and analyzed the results with bivariate and multivariate statistics.