Purpose: The digitization of the dental field has been vigorously promoted in recent years. An impression using an intraoral scanner is considered to significantly change future dental treatment. The purpose of this review is to evaluate accuracy and practicality of various intraoral scanners and verification method of intraoral scanners.

Study selection: This review was based on articles searched through the MEDLINE and PubMed databases. The main keywords that were employed during the search were "Oral Scanner, Intraoral Scanners, Desktop Scanner, and Digital Impression".

Result: It was reported that illuminance and color temperature affected trueness and precision of intraoral scanners. The repeatability of intraoral scanners indicated the possibility of producing fixed prostheses within the range of being partially edentulous. It is considered difficult to use intraoral scanners in fabricating cross-arch fixed prostheses. However, with intraoral scanners, it may be considered possible to fabricate mouth guards and dentures equivalent to those of desktop scanners. Current intraoral scanner scans are considered more comfortable than traditional impressions that use irreversible hydrocolloid and elastomeric impression materials.

Conclusion: Since the intraoral scanner is an evolving device, further improvement in accuracy is expected in the future. In addition, verification of the accuracy of intraoral scanners must be conducted accordingly.

Purpose: Titanium and titanium alloys are one of the main metallic materials in the medical and dental fields because of their biocompatibility. In this review, the application of titanium and its alloys as the substitute materials for Ag–Pd–Au alloy in the casting of fixed dental prostheses was examined.

Study selection: A reference search was performed through PubMed based on the keywords titanium, titanium alloy, and dental casting. Other relevant references were obtained from the citation in the articles.

Results: The dental casting technology for titanium has already been developed for clinical use, which enables the use of appropriate casting machines and investment materials for titanium and its alloys available commercially. The mechanical properties, castability, and corrosion resistance of titanium and titanium alloys were reported to be comparable or superior to the conventional dental alloys. Clinical researches reported that titanium and Ti-6Al-7Nb alloy casings showed suitable quality for clinical application.

Conclusion: Titanium and its alloys can be the substitute materials for Ag–Pd–Au alloy, and should be considered worthy of qualifying for the dental insurance coverage.

Purpose: This systematic review aimed to provide an overview of zirconia implants as well as regarding the outcome of the implant-restorative complex in preclinical studies.

Study selection: An electronic search of the literature prior to July 2017 was performed to identify all articles related to preclinical research on zirconia implants. The search was conducted using MEDLINE (National Library of Medicine) and PubMed without restrictions concerning the date of publication. The search terminology included: zirconia implant, osseointegration, bone-to-implant contact, soft tissue, histology, histomorphometry, surface modification, surface roughness, surface characteristics, and restoration (connecting multiple keywords with AND, OR).

Results: Fifty-seven studies were finally selected from an initial yield of 654 titles, and the data were extracted. The identified preclinical studies focused on several aspects related to zirconia implants, namely biocompatibility, mechanical properties, implant design, osseointegration capacity, soft tissue response, and restorative options. Due to heterogeneity of the studies, a meta-analysis was not possible. The most frequently used zirconia material for the fabrication of implants is yttria-stabilized tetragonal zirconia polycrystal. The resistance-to-fracture for zirconia implants ranged between 516–2044 N. The mostly investigated parameter was osseointegration, which is compared to that of titanium. A lack of evidence was found with other parameters.

Conclusions: Due to its good biocompatibility as well as favorable physical and mechanical properties, zirconia implants are a potential alternative to titanium implants. However, knowledge regarding the implant-restorative complex and related aspects is still immature to recommend its application for daily practice.

Purpose: To evaluate the substrate masking ability of different ceramic systems used for complete crowns and assess the influence of their association with an opaque resin-based luting agent (OLA).

Methods: Eleven ceramic groups were tested (n = 10). Bilayer groups were: ZrPc — zirconia + porcelain; CAD-onHT — zirconia + high translucent lithium disilitace; CAD-onLT — zirconia + low translucent lithium disilicate; LDPc — high opaque lithium disilicate + porcelain. Monolithic groups were: TZ — high translucent zirconia; TLS — translucent, zirconia-reinforced lithium silicate; HTLS — high translucent, zirconia-reinforced lithium silicate; LTLD — low translucent lithium disilicate; HTLD — high translucent lithium disilitace; LGC — leucite-reinforced glass ceramic; FC — feldsphatic ceramic. The substrates adopted were resin composites shaded A1 (control), A3.5 and C4; coppery and silvery metals. Color differences (ΔE₀₀) and translucency parameter (TP₀₀) were assessed with the CIEDE2000 formula. ΔE₀₀ was obtained assessing the ceramic influence only and in association with OLA.

Results: Zirconia groups presented lower ΔE₀₀ and TP₀₀. CAD-on structures associated to OLA led to the lower ΔE₀₀ when tested over metals. ΔE₀₀ for LDPc were similar to zirconia when associated to OLA. Monolithic groups presented significant higher ΔE₀₀ and TP₀₀ compared to bilayers, with ΔE₀₀ below the acceptability threshold only when associated to OLA over substrate shade A3.5.

Conclusions: Ceramic type and the white-opaque resin-based luting agent presented a significant effect on the substrate masking ability. All the discolored substrates tested are adequately masked with veneered zirconia or with LDPc (preferably associated to OLA). The CAD-on technique associated with OLA improved the masking ability over metallic substrates.

Purpose: The aim of this study was to determine the influences of oral motor function such as tongue function and bite force on masticatory performance in the elderly.

Methods: We randomly selected 245 subjects who has 28 natural teeth among community-dwelling elderly. We evaluated masticatory performance using a gummy jelly, and also measured bite force, tongue muscle force, and the speed of tongue movement.

Results: We found that reduced masticatory performance to be associated with decreased the speed of tongue movement and/or tongue muscle force, indicating that reduced oral motor function also influences masticatory performance.

Conclusions: These results suggest that keeping oral motor function, as well as maintenance of occlusal support, to be important for maintaining masticatory function in the elderly.