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Computer-aided design-computer-aided manufacturing (CAD-CAM) systems have been widely used as a fabrication method for restorations because of their high efficiency and accuracy, which significantly reduces fabrication time. However, molars with insufficient clearance or short clinical crown lengths require retention holes or grooves on the preparation, making it difficult to replicate the shapes with the CAM milling system. In these cases, restorations using the lost-wax method are selected. This article focuses on one-piece endodontic crowns (endocrowns) fabricated with a CAD-CAM system (CAD-CAM endocrowns), in which their posts and crowns are integrated. Articles from July 2012 to August 2023 were searched in PubMed with the keyword ''endocrown''. This review discusses the application of CAD-CAM endocrowns to molars from the viewpoint of model experiment (fracture resistance, adaptation) and clinical research. This technique, which allows margins and internal gaps to be set within the clinically acceptable range, is reported to be an effective way of restoring molars with high survival rates in clinical research.

Background/purpose: Bone resorption inhibitors, such as bisphosphonates (BPs) and anti-receptor activator of nuclear factor kappa B ligand antibodies (denosumab; Dmab), are used to treat osteoporosis and effectively reduce the risk of fracture. However, medication-related osteonecrosis of the jaw (MRONJ) has been reported as a rare adverse effect. Invasive tooth extraction procedures are reportedly a factor in the development of MRONJ. In this study, we aimed to retrospectively observe and clinically examine the effect of medication status on MRONJ development after tooth extraction in patients receiving drug treatment for osteoporosis. Materials and methods: This study was conducted among patients who visited our hospital between December 2015 and December 2021. We collected and analyzed the medical information of patients who underwent dental extractions while using osteoporosis medications, including oral and injectable BPs and Dmab. Results: Among antiresorptive medication users, 40 patients (70 teeth) underwent extraction. The mean duration of BP/Dmab use was 40.4 months, and the mean duration of drug holiday was 6.9 months. MRONJ after tooth extraction was not seen in BP users, but we observed two cases in Dmab users. A significant difference in MRONJ development was confirmed with the use of injectable compared with oral medication administration (odds ratio＝5.01). Conclusion: The use of injectable bone resorption inhibitors was associated with a higher risk of developing MRONJ. The route of administration, duration of medication, and withdrawal period should be carefully considered to prevent MRONJ after tooth extraction.

Abstract Background The pathophysiology and pathology of peri-implantitis remain unclear; however, its similarity to periodontitis has been described. The evaluation of peri-implant tissue and the diagnostic criteria of peri-implant disease are not currently standardized as they are for periodontitis. In this study, we evaluated clinical parameters during the implant maintenance period to determine significant correlations between these parameters. Methods We examined 55 implant patients at the time of maintenance visits between April and September 2016 and classified patients into a healthy group (H) and a history-of-periodontitis group (HP). For each implant, we evaluated the modified plaque index, probing pocket depth, and bleeding on probing as clinical parameters. Statistical analyses were performed with Spearman’s rank correlation coefficient. Results A total of 130 implants were assessed. The mean time since implant placement was 6 years and 6 months. The prevalence of implant-based peri-implantitis was 10.8% of all the implants. All cases of implant-based peri-implantitis came from the HP group, and many were present in patients with a history of severe periodontitis. The probing pocket depth around the implant was significantly greater in the HP group than in the H group. We found weak positive correlations between the probing pocket depth and bleeding on probing (r s = 0.401, p

Purpose: The main objective of this study was to investigate the efficacy of S-PRG filler-containing gel application in promoting dentin remineralization using ultrasonic velocimetry. Methods: Root dentin slabs of bovine teeth were sliced and formed into rectangles, treated with 0.1 M lactate buffer (pH 4.75) for 10 min, and then immersed in artificial saliva (pH 7.0). This treatment was repeated three times a day for 28 days. S-PRG filler-containing gel (PRG) and high-fluorine concentration silver diamine fluoride (SDF) solution were used. The treatment methods were: 1) untreated group, 2) PRG one-off application group, 3) SDF oneoff application group, 4) PRG frequent-time application group, and 5) SDF frequent-time application group. After treatment, dentin slabs were soaked in 0.1 M lactate buffer solution and dipped in artificial saliva. This treatment was repeated 3 times a day for 28 days. Results: The ultrasonic velocity of the untreated samples decreased slightly during the experimental period. In the one-off application group, ultrasonic velocities of SDF and PRG increased rapidly on day 7 and then decreased slightly during the experimental period. In the frequent-time application group, ultrasonic velocities of SDF and PRG increased during the experimental period; specimens treated with SDF had significantly higher ultrasonic velocities on each measurement day compared to specimens treated with PRG. Conclusion: From the results of this experiment, it was concluded that the S-PRG filler-containing gel and silver diamine fluoride solution appear to promote remineralization and inhibit dentin demineralization. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the bonding performance of self-adhesive flowable resin composites (SARs) to bovine teeth. Three SARs, one experimental, and two commercially available products, were used. The study parameters were shear bond strength (SBS), microleakage, and scanning electron microscopy (SEM) evaluation of bonding interfaces. The SBS of the materials was 14.1–15.1 MPa to enamel, 22.2–23.2 MPa to etched enamel, and 7.4–10.7 MPa to dentin. Specimens with pre-etching showed lower microleakage scores than those without pre-etching. SEM images of the interfaces of the materials showed excellent adaptation regardless of the substrate or etching mode. The study results indicate that enamel pre-etching can improve the bonding performance of SARs. [ABSTRACT FROM AUTHOR]

This study aimed to observe and compare the resin luting cement (RLC)/dentin interfaces of different types of RLC systems with scanning electron microscopy (SEM). This study evaluated six self-adhesive resin luting cement systems (SARLCs), four systems combining a SARLC with a tooth primer (SARLCPs), and six conventional resin luting cement systems (CVRLCs). Cured resin composite rods were bonded to bovine dentin using RLCs in different etching modes. The morphological features at the interfaces were observed using SEM. Although all RLCs in etch-&-rinse (ER) mode showed a clear hybrid layer, most SARLCs had a thinner and more porous hybrid layer than the SARLCPs and CVRLCs. All SARLCPs with primer and CVRLCs showed a thin high-density layer below the primer layer in both etching modes. CVRLCs and SARLCPs with primer treatment systems may be more versatile and reliable when compared to simplified RLC systems [ABSTRACT FROM AUTHOR]

Purpose: To investigate the changes in the enamel bond performance of a two-step adhesive containing a primer derived from a universal adhesive in the early phase before 24 h and compare them to those of other adhesives. The Knoop hardness number (KHN) of the cured adhesive layers and resin composite was measured. Materials and Methods: A new two-step adhesive using universal adhesive technology, G2-Bond Universal, was tested. Two conventional two-step adhesives, Clearfil SE Bond 2 and OptiBond eXTRa, and an established universal adhesive, Scotchbond Universal Plus Adhesive, were used as comparison materials. Twelve specimens per group were used to measure the shear bond strength (SBS) to bovine enamel in different etching modes. The bonded specimens were stored in distilled water at 37°C for 5 min or 1, 6, 12, or 24 h before SBS testing. The KHN of the adhesive layer and resin composite was determined after the same storage periods as for SBS testing. Results: All adhesives exhibited increased SBS with prolonged storage periods, irrespective of the etching mode. The KHN of the adhesive layer and resin composite increased over time. Conclusions: There were strong positive correlations between the SBS and KHN of the adhesive layer and resin composite. Phosphoric acid pre-etching of enamel effectively increases enamel bond performance. The two-step adhesive G2-Bond Universal demonstrated significantly higher bond strength in the early phase than the other adhesives in self-etch mode. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the influence of surface pretreatment on the shear bond strength of resin luting cement to saliva-contaminated resin core foundation. The surface free energy (γS) of the adherent surfaces was examined. The two-way analysis of variance revealed that the surface pretreatment and storage conditions had a significant effect on the strength of the bond to resin core foundation. The γS values of the saliva-contaminated group were significantly lower than those of the other groups, and they tended to improve after surface pretreatment. The tendency of improvement in γS values differed depending on the type of pretreatment agents. Surface treatment with solutions containing functional monomers is effective in removing saliva contaminants from the resin core foundation surfaces and in creating an effective bonding surface for the resin luting cement [ABSTRACT FROM AUTHOR]

This study aimed to determine the influence of surface roughness of the color adjustment potential restoration of universal resin composites. A structural colored resin composite (Omnichroma, OC) and a pigment-employed universal shade resin composite (Beautifil Unishade, BU) were used. Each resin composite was placed in a cavity to determine its ability to match the color of artificial teeth. The surface of the resin composites was polished with #800- or #2000-grit SiC paper before performing color measurements. One-way analysis of variance and Tukey post hoc tests were performed (a=0.05). The color difference (ΔE*ab) ranged from 2.5-3.9 for OC and 1.8-8.7 for BU. OC has a more stable color adjustment than BU. The color adjustment potential of universal resin composites was affected by the surface roughness of the restorations. [ABSTRACT FROM AUTHOR]

Purpose: Medication-related osteonecrosis of the jaw (MRONJ) is characterized by necrosis of the jawbone with intraoral bacterial infection and has a significant negative impact on oral health-related quality of life. Risk factors for the onset are unknown, and definitive therapeutic approaches have not yet been defined. A case-control study at a single institution in Mishima City was conducted. The purpose of this study was to examine in detail the factors that contribute to the development of MRONJ. Methods: Medical records of MRONJ patients who visited Mishima Dental Center, Nihon University School of Dentistry, during the period 2015-2021 were extracted. Counter-matched sampling design was used to select participants matched for sex, age, and smoking for this nested casecontrol study. The incidence factors were statistically examined by logistic regression analysis. Results: Twelve MRONJ patients were used as cases and 32 controls were matched. After adjustment for potential confounders, injectable bisphosphonates (aOR = 24.5; 95% CI = 1.05, 575.0; P < 0.05) were significantly associated with the development of MRONJ. Conclusion: High-dose bisphosphonates may be a risk factor for the development of MRONJ. Patients who use these products require careful prophylactic dental treatment against inflammatory diseases, and dentists and physicians should maintain close communication. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of polymerization methods and a metal priming agent on the bond strength between gold alloy for metal ceramic restorations and dual-cure-type resin luting agents, and on the strength and hardness of the luting agents.Methods: A total of 154 disks cast by a gold alloy were treated with or without a metal priming agent. One of the three luting agents was applied on the disk. The luting agent was either chemically or dual-polymerized. The shear bond strength was measured both before and after thermocycling. In addition, scanning electron microscope (SEM) observation, flexural strength test, and Knoop hardness test were performed.Results: Significant differences among the luting agents were observed in terms of bond strength and flexural strength. Significant differences between chemically and dual-polymerized luting agents were observed regarding shear bond strength, flexural strength, and Knoop hardness before thermocycling. The application of the priming agent was effective only for a luting agent.Conclusion: Both bond strength and flexural strength differed among three luting agents. The effect of the priming agent on bond strength differed among the luting agents. Both the bond and flexural strength of a chemically polymerized luting agent differed before or after thermocycling. [ABSTRACT FROM AUTHOR]

Aims: To assess the speed and accuracy of a checklist user interface for the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Methods: A diagnostic tool formatted as a checklist was developed and compared to an existing diagnostic tool, the DC/TMD diagnsostic decision trees. Both types of tools use the DC/TMD and were tested by dental students, interns, and residents in the USA and Japan for diagnosis of hypothetical patients. The comparisons were done in a randomized, crossover, controlled, double-blinded trial. Results: Overall, subjects using the experimental tool answered 25% more correct diagnoses (P < .001) and missed 27% fewer diagnoses (P < .01). They were also able to finalize their diagnoses faster than those using the control tool, in 16% less time (P < .05). The difference in accuracy was more pronounced in complex cases, while the difference in speed was more pronounced in simple cases. Conclusion: This checklist is an alternative user interface for the DC/TMD. [ABSTRACT FROM AUTHOR]

Recently, wearing a mouthguard (MG) has become mandatory in contact sports. A properly fitted MG protects against sports injuries to the stomatognathic system, and stabilized the occlusal position, which might leads to improved sports performance. The present study uses a questionnaire to determine the amount of dental knowledge and motivation to wear a MG among dental college students. The current situation regarding MG use, discomfort, and experience of oral trauma and concussion was evaluated in 175 rugby football players, 63 American football players, 62 skiers, 55 karate, 27 Shorinji kempo and 32 Nippon kempo athletes who participate d in the Annual Athletic Meet for All Japanese Dental Students (414 participants). The results of the questionnaire about MG use indicated that almost all players experienced discomfort. Dental trauma was experienced in 90% and 43% of rugby football payers and karate athletes, respectively. The rates were lowest among American football players, Shorinji kempo athletes and skiers, being 5.8%, 7.4%, 12.9%, respectively. Concussion was experienced by > 36% of rugby football players and 25% of Nippon kempo athletes. Nippon kempo athletes may use a MG to protect against concussion. In conclusion, rules requiring players to wear a MG should be enforced or rules should be changed to make wearing a MG compulsory, awareness of dental students should be improved, injury should be prevented by wearing a MG and not only organizations but individual players should be educated about the necessity of wearing a MG. [ABSTRACT FROM AUTHOR]

Cast titanium restoration for molars has high biocompatibility and is covered by the Japanese national health insurance. Titanium casting requires specific investment material and casting apparatus. A cast restoration for the mandibular left second molar was fabricated using titanium in this study. A wax pattern fabricated on a definitive cast was invested in calcium aluminate-bonded magnesia investment material. Titanium was cast using an argon gas pressure one-chamber casting apparatus. No defects were observed on the surface and the hole was clearly reproduced. A smooth surface on the restoration was obtained by polishing at low speed. Reproductivity and polishing properties of the titanium restoration fabricated in this study were comparable to those of conventional dental metal restorations. [ABSTRACT FROM AUTHOR]

The outbreak of novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide. Nasopharyngeal swabs are widely used in polymerase chain reaction (PCR) test to detect SARS-CoV-2. However, the collection of nasopharyngeal swabs has a series of drawbacks concerning exposure of healthcare staff, difficulty in collection, and discomfort of patients. Therefore, an alternative noninvasive sample for diagnostic of emerging viral diseases is required. The usefulness of saliva screening tests is compared to conventional swab tests in this report. The results suggest that saliva could be a reliable sample for detecting SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the influence of surface pretreatment on the shear bond strength (SBS) of a resin luting cement to enamel and dentin with saliva contamination. The surface free energies (SFE) of the adherent surfaces were also determined., Methods and Materials: Bovine enamel and dentin were used in this study. For the saliva-contamination, human saliva was applied to the adherent surface for 60 seconds and then air-dried, and the specimens without saliva contamination served as controls. One group of contaminated surfaces was untreated (SC), and the others were pretreated with Katana Cleaner (KC), Multi Etchant (ME), or Ultra-Etch (UE). Fifteen specimens were prepared to measure the SBS for each test group.The mixed resin luting cement paste was applied to the alumina-blasted surface of a stainless-steel rod and placed on the prepared tooth surface. The luting cement was light irradiated for 40 seconds. The bonded specimens were stored for 24 hours at 37°C and half of the bonded specimens underwent 10,000 thermal cycles. The SBS and SFE of the specimens after different pre-treatments were measured., Results: The two-way ANOVA revealed that the factors of pretreatment agent and storage condition had a significant effect on the SBS to enamel and dentin. The SFE values of the SC group were significantly lower than those of the other groups in both enamel and dentin. The SFE of pretreated surface was material dependent., Conclusions: A pretreatment agent containing functional monomers was shown to be effective in removing saliva contaminants and in creating an effective bonding surface for the resin luting cement., (©Operative Dentistry, 2024.)