The Effect of Brand, Thickness, and Abutment Substrate on the Masking Ability of Monolithic Zirconia Cera The goal of the present study was to determine the minimum thickness of monolithic zirconia required to achieve an acceptable masking ability and to examine how brand, thickness, and abutment substrate influenced that masking ability (∆E). Seventy-two A2-shade monolithic zirconia disc specimens in various thicknesses (1.0, 1.5, and 2.0 mm) were fabricated using three brands: Nacera® Pearl 1, DD cubeX2 and XTCERA TT. A spectrophotometer was used to determine the CIELab values of the specimens, which were placed on a D4-shade resin composite and white acrylic (control) substrates. The ∆E was calculated and compared with the acceptable (AT = 5.5) and perceptible (PT = 2.6) tolerance thresholds. Further investigation was conducted on 72-disc specimens from the monolithic zirconia brand with the best masking ability on D3-shade resin composite and semi-precious alloy. Using two-way ANOVA, the interaction of thickness, brand, and abutment substrate on ∆E was investigated. Nacera® Pearl 1 at 1.5 mm thickness was sufficient to achieve AT on a D4-shade resin composite substrate, whereas 2.0 mm of DD cubeX2 and XTCERA TT were required. Nacera® Pearl 1 further testing on two other substrates requires thicknesses of 1.5 mm and 1.0 mm, respectively. Only the Nacera® Pearl 1 group achieved PT on D3- and D4-shade resin composite (2.0 mm) and semi-precious alloy substrates (1.5 mm). Brand, thickness, and abutment substrate influenced the ∆E (p < 0.001). To achieve an acceptable masking ability, the minimum thickness of monolithic zirconia tested on D3- and D4-shade resin composite and semi-precious alloy should be around 1.5 mm to 2.0 mm.

Poly-Ether-Ether-Ketone (PEEK) Removable Partial Dentures: A Scoping Review This scoping review aims to comprehensively assess the existing evidence from both clinical and in vitro studies concerning removable partial dentures (RPD) made from poly-ether-ether-ketone (PEEK) to identify current research gaps and enhance the understanding of PEEK’s viability as a material for RPD. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews was applied. A search was made using PubMed, Web of Science, Elsevier’s Scopus, ProQuest and Springer Link databases for articles in the English language up to November 2023, focusing on case reports, clinical, and in vitro studies. A total of 33 studies were included in the analysis, which consisted of 4 case reports, 6 clinical studies, and 23 in vitro studies. Clinical studies predominantly examined patient satisfaction post-PEEK RPD insertion, framework accuracy, dimensional changes in residual ridges, and fungal/bacterial adhesion to PEEK. In vitro studies emphasized retentive force clasps (12 studies), accuracy and fitness (5 studies), material staining effects (3 studies), and diverse surface treatments (3 studies). The current body of evidence reveals a scarcity of clinical studies investigating PEEK as an RPD framework. In vitro studies primarily focused on assessing material retentive forces, with limited attention given to accuracy, surface treatment, and staining of denture base materials. Future research should address these gaps, exploring aspects such as adhesion and biofilm formation (e.g. Candida albicans) on RPD surfaces. Rigorous, well-designed clinical trials and expanded in vitro investigations are essential to establish PEEK RPD as definitive prostheses for partially edentulous patients.

SCIENCE MAPPING OF RESEARCH CLUSTERS AND CORE RESEARCH AREAS IN REMOVABLE PARTIAL DENTURES Science mapping helps provide a comprehensive review of a topic of interest based on the enormous scientific output in the academic literature. The study aims to identify research clusters, core research areas, and the highest impact terms based on the co-occurrence of keywords in removable partial dentures (RPDs) research for the past ten years, from 2012–2022. The search was done using the truncated search term "removable partial denture*" OR "removable prostho*" based on the papers extracted from the Scopus database, and a bibliometric analysis tool was employed to automate keyword mapping. Data analysis and visualisation were done using Biblioshiny software (RStudio Desktop) and VOSviewer (Version 1.6.18). The search yielded 1043 articles following the refinement criteria. Data was cleaned to remove duplication and exclude irrelevant topics, leaving 888 documents from 114 journals to be analysed. From the 679 keywords extracted, six clusters were identified, enabling researchers to find research clusters: cluster 1 (predominantly complete dentures and shortened dental arches), cluster 2 (clasp in relation to materials), cluster 3 (latest technologies in RPDs fabrication), cluster 4 (implant-related), cluster 5 (quality-of-life (QoL)) and cluster 6 (abutment teeth). For the year 2012-2022, further analysis reveals that “polyetheretherketone (PEEK)”, “3D-printing”, and “systematic review” were identified as the top three high-impact terms based on the annual citation and annual normalised citation scores. Research on "implant’ and "oral health QoL" has been identified as primary core research areas in RPDs-related research from 2012-2017, while “CAD-CAM”, “3D-printing”, “clasp" and “PEEK” emerged as new areas of interest among researchers in 2018-2022. PEEK has been identified as the highest impact term for the past ten years, highlighting the possible future research interest in RPDs-related research. Incorporating digital technologies in RPDs fabrication using high-performance polymers as materials is expected to increase in the future.

FRACTURE TOUGHNESS AND FRACTURE MODE OF CEMENT-RETAINED VERSUS SCREW-RETRIEVABLE CEMENT-RETAINED IMPLANT-SUPPORTED CROWNS: A PILOT STUDY The aim of this pilot study was to compare the fracture toughness and fracture mode of cement-retained versus screw-retrievable cement-retained implant-supported monolithic zirconia crowns. Ten implant-supported crowns were made from monolithic CAD/CAM zirconia and equally divided into control and test groups. The control group received cement-retained monolithic zirconia crowns (CR), while the test group received screw-retrievable cement-retained monolithic zirconia crowns (SRCR). The crowns were then bonded to prefabricated Variobase titanium-based abutments with resin luting cement. To simulate the aging process in the oral cavity, all samples were undergone thermal cycling machine. After ageing, each group underwent a single load fracture test to analyze the fracture load, and the fracture mode was evaluated using scanning electron microscopy (SEM). The Mann-Whitney U test was used to compare fracture toughness, and statistical significance was set at p<0.05. The mean fracture toughness of CR crowns was 2945.49 ± 511.426 N, while that of SRCR crowns was 2897.82 ± 510.837 N, but the difference was not significant (U=10, p= 0.917). SEM examination revealed that all failures originated from the fitting surface of the crowns. The titanium-based abutment remained intact in all specimens. Within the limitations of this pilot study, the CR showed higher fracture toughness than SRCR implant crown, but both specimen fracture at six times more than the average maximum bite force of posterior tooth. The presence of screw access in SRCR has affected the fracture mode.

The objective of this study was to characterise articles published in removable partial denture (RPD) research from 1948 to 2022 to identify the most influential journals, publications, authors, and core research areas using bibliometric analysis. The Scopus database was used to retrieve publications with titles containing the truncated search term (“removable partial denture*” OR “removable prostho*”). Data analysis and visualisation were done using Microsoft Excel, Biblioshiny software and VOSviewer. A total of 2,484 articles were analyses from 1948 till 2022, representing an annual growth rate of 4.9%. The Journal of Prosthodontic Research demonstrated the highest average normal citation rate, with productive authors with highest citations being from Japan. From 1948 to 1999, most in-vitro and clinical research focused on the basic concept of RPD using cobalt-chromium as a framework before shifting to titanium in 2000. RPD research after 2012 focuses on new technology and non-metalbased frameworks as an alternative to metal-based frameworks. Wakabayashi and Fueki were the most prominent researchers, according to a three-field plot analysis, with the Journal of Prosthetic Dentistry, Journal of Oral Rehabilitation, and Journal of Prosthodontic Research among the authors’ preferred journals. “CAD/CAM” and “3D printing” were identified as emerging themes in year 2020 to 2022, while “selective laser melting” was the trending keyword in 2017 to 2019. Research on “oral health and quality of life” has been identified as core research area in RPD-related research. RPD research on digital dentistry and new framework materials is anticipated to increase in the future with the incorporation of research on quality of life.

The aim of this review was to provide an update on the current status of digital occlusal force measurement devices, as well as clinical and research applications in complete arch maximum occlusal force measurement. SCOPUS, ScienceDirect, and PubMed databases were used to conduct a literature search from January 2001 to January 2021. Identification and screening of literature were done independently according to published guidelines and selection criteria. The electronic searches turned up 394 articles, 16 of which met the inclusion and exclusion criteria and were selected for study analysis. All of these studies used T-scan and Dental Prescale digital occlusal analysis system with pressure-sensitive foils as occlusal force measurement devices. The devices showed a promising potential for identifying and comprehending maximum occlusal forces objectively. According to the current review, maximum occlusal force measured with digital occlusal force devices can be used as a prosthodontic adjunct to address issues that arise during the treatment of occlusal disorders, temporomandibular disorders, and complete dentures. It is also useful in predicting cognitive and functional decline in the elderly.

Custom cast metal posts and cores are time-consuming to make, requiring several clinical and laboratory stages and the use of gold, cobalt-, or nickel-chromium. Aside from the numerous stages involved, a cast metal post and core has a significantly higher modulus of elasticity than the dentinal root structure and, as a result, is more likely to cause root fracture. Furthermore, the metal colour of the post and core, which always appears as a dark shadow beneath a ceramic crown, is an aesthetic concern. Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) of posts and cores is a potential fabrication option for overcoming the issues associated with cast metal posts and cores. Some of the time-consuming clinical and laboratory procedures can be eliminated by using a CAD/CAM machine, and tooth-colored materials can be milled to create custom posts and cores. The marginal and internal adaptation of the CAD/CAM produced posts and cores to the tooth structure, on the other hand, is highly dependent on the scanning accuracy and milling capability of the CAD/CAM machine. Because the majority of studies on dental CAD/ CAM have concentrated on the fabrication of fixed and removable prostheses, data on the marginal accuracy and internal adaptation of CAD/CAM produced posts and cores is limited. As a result, the aim of this review paper is to determine the current state of the market’s CAD/CAM machines in terms of their scanning and milling capability to produce custom posts and cores that match the marginal and fitting accuracy of cast metal posts and cores.

The continuous sequence of bone healing phases starts off with osteoconduction to the implant surface, depending on the migration of osteogenic cells. Osteoneogenesis ensues resulting in a mineralised interfacial matrix and is followed by bone remodelling to the implant interface at discrete sites. Dental implant drilling procedure and placement produce osseous defect which is filled by blood. Within seconds, blood proteins are adsorbed onto the implant surface and platelets are activated resulting in the release of cytokines and growth factors. Further platelet aggregation initiates osteoconduction to the surface, followed by osteoneogenesis, forming an extracellular matrix. Subsequently, remodelling creates a bone to implant interface which can be explained through distance and contact osteogenesis. The dental implant surface has been shown to influence osteoconduction by modifying protein properties and adsorption around the implant. Salivary biomarkers may be considered as a specific and sensitive diagnostic tool to detect these changes in protein expressions after implant placement. Thus, the purpose of this narrative review is to provide a detailed account of the bone healing mechanism associated with dental implant placement, as well as how the implant surface architecture and protein release play a role in bone healing, and the potential use of saliva to detect these biomarkers.

BACKGROUND: Prolonged standing has been hypothesized as a vital contributor to discomfort and muscle fatigue in the workplace. The objective of this study was to develop a decision support system that could provide systematic analysis and solutions to minimize the discomfort and muscle fatigue associated with prolonged standing. METHODS: The integration of object-oriented programming and a Model Oriented Simultaneous Engineering System were used to design the architecture of the decision support system. RESULTS: Validation of the decision support system was carried out in two manufacturing companies. The validation process showed that the decision support system produced reliable results. CONCLUSION: The decision support system is a reliable advisory tool for providing analysis and solutions to problems related to the discomfort and muscle fatigue associated with prolonged standing. Further testing of the decision support system is suggested before it is used commercially.
Fatigue ; Human Engineering ; Muscle Fatigue

The aim of the Fourth Millennium Developmental Goal is to reduce mortality among children less than 5 years by two thirds between 1990 and 2015. Efforts are more focus on improving children’s health. The aim of this study was to describe the trend of stillbirth and neonatal deaths in University Kebangsaan Malaysia Medical Centre from 2004 to 2010. A retrospective cross-sectional study was conducted using hospital data on perinatal mortality and monthly census delivery statistics. There were 45,277 deliveries with 526 stillbirths and neonatal deaths. More than half of the stillborn cases were classified as normally formed macerated stillbirth and prematurity was common in neonatal deaths. The trend of SB and NND was found fluctuating in this study. However, by using proportionate test comparing rate, there was a transient significant decline of stillbirth but not neonatal deaths rates between 2004 and 2006. On the other hand, the neonatal deaths rate showed significant increment from 2006 to 2008. When both mortality rates were compared using proportionate test, from the start of the study, year 2004 with end of the study, year 2010, there was no significant decline noted. Trends of stillbirth and neonatal death rates in University Kebangsaan Malaysia Medical Centre within 7 years study period did not show the expected outcome as in Millennium Developmental Goal of two thirds reduction.
Stillbirth ; Infant Mortality