Influence of etching mode on bonding performance of self-adhesive flowable resin composites to bovine teeth.

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.

Application of one-piece endodontic crowns fabricated with CAD-CAM system to molars.

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.

Influence of different curing modes on the bonding effectiveness of self-adhesive resin luting cements in combination with universal adhesives.

OBJECTIVES: This study aimed to investigate the immediate dentin bond performance and bond durability of self-adhesive resin luting cements (RLCs) in combination with universal adhesives in different curing modes. METHODS: Two self-adhesive RLCs were used with universal adhesives as primers. They were also used alone as self-adhesive RLCs. Two multiple-step RLC systems were used as comparison materials. To measure the shear bond strength (SBS) in different curing modes, 12 specimens were prepared for each group. Stainless-steel rods were bonded to bovine dentin, and the bonded specimens were assigned to the baseline group (stored for 24 h) and artificially aged group (thermal cycling [TC], 10,000 cycles). After each storage period, the SBS of the bonded specimens was measured. The Knoop hardness number (KHN) of the cured RLCs was measured with or without primer application in different curing modes at 24 h and after 10,000 TC. The representative RLC/dentin interfaces were observed using scanning electron microscopy (SEM). RESULTS: Dentin SBS was significantly influenced by the RLC system but not by the curing mode. Self-adhesive RLCs alone showed significantly lower SBS values than self-adhesive RLCs with primer regardless of the curing mode or storage period. The storage period, curing mode, and RLC system significantly influenced the KHN. SIGNIFICANCE: The use of universal adhesives as a primer may help enhance the immediate dentin bond performance and bond durability of self-adhesive RLCs.

Scanning electron microscopy observation of dentin bond interfaces in different types of resin luting cements.

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.

Treatment of saliva contamination of resin core foundation before adhesive luting.

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.

Influence of surface roughness of universal shade resin composites on color adjustment potential.

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 (α=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.

A nested case-control study of factors contributing to the development of medication-related osteonecrosis of the jaw in patients using bone resorption inhibitors in Mishima City.

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 case-control 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.

Whitening efficacy and tooth sensitivity in a combined in-office and at-home whitening protocol: A randomized controlled clinical trial.

OBJECTIVE: This controlled randomized clinical trial determined the whitening efficacy and the intensity and absolute risk of tooth sensitivity in dual whitening when prefilled at-home whitening trays were used between in-office whitening intervals. MATERIALS AND METHODS: An in-office whitening agent containing 35% hydrogen peroxide was used. A prefilled tray with a whitening agent containing 6% hydrogen peroxide was used for at-home whitening. Sixty-six subjects were randomly assigned to three groups. Group I: at-home whitening was performed 10 times between the in-office whitening treatments. Group II: at-home whitening was performed five times between the in-office whitening treatments. Group III: only in-office whitening was performed. The tooth color changes were evaluated using a spectrophotometer. A visual analog scale was used to express the pain intensity. RESULTS: All the groups showed increased ΔE*ab, ΔE00 , and ΔWID with increased whitening sessions. Group I at the 3rd whitening session showed significantly higher ΔE*ab, ΔE00 , and ΔWID than group III. Tooth sensitivity showed higher values up to 24 h after whitening. CONCLUSIONS: Although dual whitening with the prefilled tray and in-office whitening had higher whitening ability than in-office whitening alone, the intensity and absolute risk of tooth sensitivity was similar. CLINICAL RELEVANCE: The dual whitening might produce faster and stronger whitening effects than in-office whitening alone.

Early Phase Enamel Bond Performance of a Two-step Adhesive Containing a Primer Derived from a Universal Adhesive.

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.

Medication-related osteonecrosis of the jaw after tooth extraction in patients receiving pharmaceutical treatment for osteoporosis: A retrospective cohort study.

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.

Usage of English prosthodontic terms 2019 in Japan.

The use of a uniform terminology is important to avoid misunderstanding of concepts or procedures in discussion. The usage of English prosthodontic terms in Japan was investigated in the current study. English prosthodontic terms listed in The Glossary of Prosthodontic Terms edited by the Japan Prosthodontic Society (GPTJ-5) were compared to those in The Glossary of Prosthodontic Terms ninth edition (GPT-9). A small number of terms labeled as objectionable in GPT-9 were listed in GPTJ-5. This might indicate that it takes a long time to replace terms that are used widely.

Correlations between implant success rate and personality types in the older people: A preliminary case control study.

Background/ purpose: Older patients inevitably have a higher need for implant treatment, it is unknown how mental changes or psychological aspects affect the outcome of implant treatment. This study evaluated the success rate of implants and the influence of personality traits in the older people. The goal was to provide evidence for predictable implant treatment while taking into account the unique psychological changes of elders. Materials and methods: Participants were patients who were able to independently visit our hospital between March 2004 and May 2021. Inclusion criteria were patients aged 65 years or older at the time of implant placement with regular follow-up for at least 1 year. The implant success rate was calculated by counting peri-implantitis and implant loss as failures. Multivariate analysis was used to examine the effect of patient personality characteristics on the success rate. Results: Fifty-six implants were included in 23 patients (12 men, 11 women), with a mean age of 68.5 years (65-76) and mean maintenance duration of 9 years and 2 months. The cumulative survival rate was 87% at the patient level (94.6% at the implant level). Statistically significant differences were found for adaptive traits (odds ratio [OR] = 0.04) and non-adaptive traits (OR = 6.38); however, no significant differences were found for the other independent variables. Conclusion: The overall implant success rate was 69.6% at the patient level (82.1% at the implant level). The personality traits in older people had a significant effect on the implant failure rate.

Influence of bonding agent application method on the dentin bond durability of a two-step adhesive utilizing a universal-adhesive-derived primer.

This study investigated the effect of the bonding agent application method on the dentin bond durability of a two-step adhesive utilizing a universal-adhesive-derived primer. The bonding durability of a universal adhesive was compared with those of two conventional two-step adhesives by shear bond strength testing after thermal cycling. The primer was applied (with or without phosphoric acid pre-etching), and the specimens were divided into three groups based on the bonding agent application method used as follows: (i) strong air-flow application, (ii) gentle air-flow application, and (iii) gentle air-flow + second bonding application. The shear bond strength was determined after thermal cycling. All the factors (bonding agent application method, adhesive system, and storage condition) significantly influenced the dentin shear bond strength both with and without phosphoric acid pre-etching. The specimens exposed to gentle air-flow showed a higher shear bond strength than did those exposed to strong air-flow and gentle air-flow + second bonding. The bond durability of the tested adhesive systems was influenced by the bonding agent application method, and this trend was material dependent. The G2-Bond Universal exhibited the same or greater dentin bond durability to the other two-step adhesive systems.

Diagnostic Tool Using the Diagnostic Criteria for Temporomandibular Disorders: A Randomized Crossover-Controlled, Double-Blinded, Two-Center Study.

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.

Influence of polymerization methods and priming agents on the bond strength between resin luting agents and gold alloy.

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.

Medication-Related Osteonecrosis of the Jaw Subsequent to Peri-Implantitis: A Case Report and Literature Review.

The aim of this report was to document a rare case of medication-related osteonecrosis of the jaw (MRONJ) that developed around the already osseointegrated implants in the maxillary right molar region. A 73-year-old woman presented at our university dental hospital in May 2017 with a chief complaint of discomfort near a maxillary implant. Her first visit was in 2006, and the maintenance treatment began in 2007 after the periodontal treatment. During the implant maintenance period there were no complications; however, the patient began taking alendronate sodium hydrate (Fosamac tablets, 35 mg, once weekly), an oral bisphosphonate (BP) since 2013, for treatment of osteoporosis. Eight years after starting implant maintenance, in 2016, peri-implantitis occurred, for which mechanical cleaning and antimicrobial therapy were performed. Peri-implantitis symptoms disappeared, and the medical condition improved. Nonetheless, in 2017, MRONJ developed 4 years after she commenced taking the BP. The patient underwent implant removal and sequestrectomy. There was no postoperative recurrence. Since it was such a rare case, we performed a literature review but only discovered a few similar cases. Because various triggers may lead to the development of MRONJ, even if already osseointegrated implant, it is important to note that implants in patients taking BPs should be more carefully maintained.