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This review synthesizes the findings from 252 studies to explore the relationship between the oral pathogens associated with periodontitis, dental caries, and systemic diseases. Individuals with oral diseases, such as periodontitis, are between 1.7 and 7.5 times (average 3.3 times) more likely to develop systemic diseases or suffer adverse pregnancy outcomes, underscoring the critical connection between dental and overall health. Oral conditions such as periodontitis and dental caries represent a significant health burden, affecting 26-47% of Americans. The most important oral pathogens, ranked by publication frequency, include the herpes virus, C. albicans , S. mutans , P. gingivalis, F. nucleatum, A. actinomycetemcomitans , P. intermedia , T. denticola , and T. forsythia . The systemic diseases and disorders linked to oral infections, ranked similarly, include cancer, respiratory, liver, bowel, fever, kidney, complications in pregnancy, cardiovascular bacteremia, diabetes, arthritis, autoimmune, bladder, dementia, lupus, and Alzheimer's diseases. Evidence supports the efficacy of dental and periodontal treatments in eliminating oral infections and reducing the severity of systemic diseases. The substantial burden that oral pathogens have on cancer, cardiovascular diseases, Alzheimer's, diabetes, and other systemic diseases poses a significant public health crisis.

Purpose: To evaluate the efficacy and subjects' perception of the Modified Schirmer Test (MST) to the traditional Unstimulated Salivary Flow Test (USFT) when measuring salivary flow rate for screening and monitoring patients' dry mouth., Methods: A total of 100 subjects were enrolled including subjects with and without dry mouth. All subjects answered a brief self-reported survey about dry mouth before and after the two types of saliva tests and their preference for the type of test administered. The order of performing MST and USFT were randomized. MST was conducted by the clinician holding a Schirmer strip paper at the bottom of the subject's mouth for 1 minute. USFT was measured by having the subject spit any accumulating saliva into a medicine cup for 5 minutes. Correlation analyses were conducted to test the relationship between MST and USFT using the Pearson correlation coefficient. All analyses were performed at a P< 0.05., Results: A significant positive correlation existed between the two salivary flow tests (r= 0.556, P< 0.001). Most of the subjects (79%) preferred the MST while 6% preferred USFT; 15% reported no preference. A negative association between MST and USFT with age indicated that as age increased, subjects' salivary flow rate results for both types of tests decreased (r= - 0.287, P= 0.004)., Clinical Significance: MST provides dental care providers with an effective, economical, easy-to-perform, and patient-preferred method to screen and monitor salivary flow rate., Competing Interests: The authors declared no conflict of interest. This work was supported by the Loma Linda University School of Dentistry Student Research Program., (Copyright©American Journal of Dentistry.)

Polymers have become essential in advancing bone tissue engineering, providing adaptable bone healing and regeneration solutions. Their biocompatibility and biodegradability make them ideal candidates for creating scaffolds that mimic the body's natural extracellular matrix (ECM). However, significant challenges remain, including degradation by-products, insufficient mechanical strength, and suboptimal cellular interactions. This article addresses these challenges by evaluating the performance of polymers like poly(lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), and polylactic acid (PLA) in scaffold development. It also explores recent innovations, such as intelligent polymers, bioprinting, and the integration of bioactive molecules to enhance scaffold efficacy. We propose that overcoming current limitations requires a combination of novel biomaterials, advanced fabrication techniques, and tailored regulatory strategies. The future potential of polymer-based scaffolds in personalised regenerative medicine is discussed, focusing on their clinical applicability.

Purpose: To provide a surgical strategy for small oroantral communication closure and bone regeneration that can meet the needs of an effective, less invasive, and simpler operation by utilizing procedures and biomaterials commonly employed in guided bone regeneration techniques. The primary goal was to close the communication, while the second aim was to achieve bone regeneration., Methods: This retrospective and monocentric case series was conducted using data from the medical records of 12 subjects with oroantral communications and bone deficits greater than 3 mm who were treated with a heterologous cortico-cancellous graft covered in resorbable collagen membranes. The primary outcome was communication closure, whereas the secondary outcome was bone augmentation, which was demonstrated radiographically and clinically., Results: Twelve individuals were treated consecutively for oroantral communication closure. The subjects consisted of eight men and four women. The mean age was 57.5 years. Closure was effective in all 12 subjects, and radiographic examination after 6 months revealed bone reformation in all cases. This procedure effectively isolated the maxillary sinus from the mouth cavity, resulting in seal and healing, as well as bone regeneration., Clinical Significance: Small oroantral communications are frequent in dentistry, often requiring special expertise and interventions that affect patient morbidity. The use of a heterologous cortico-cancellous graft covered with resorbable collagen membranes can allow effective closure of the small communication, preventing migration of pathological epithelia while increasing the bone ridge., Competing Interests: The authors declared no conflict of interest. Dr. Passarelli and Dr. Lopez contributed equally to this work. Dr. Garcia-Godoy and Dr. D'Addona contributed equally to this work., (Copyright©American Journal of Dentistry.)

Purpose: To describe a surgical technique for oroantral communication closure and bone regeneration that can meet the needs of an effective, less invasive, and simpler surgery using approaches and biomaterials used in guided bone regeneration (GBR) techniques. The main objective was to close the communication, and the secondary was to achieve bone regeneration., Methods: This retrospective and monocentric case series was conducted using data obtained from the medical records of 28 patients with oroantral communications with bone deficits greater than 3 mm and treated with heterologous cortico-cancellous graft covered with resorbable collagen membranes and heterologous cortical lamina. The primary outcome was closure of the communication, and the secondary outcome was bone augmentation, both tested radiographically and clinically., Results: 28 subjects were treated consecutively for the closure of oroantral communications. The subjects included 16 men and 12 women. The mean age was 57.5 years. Closure was successful in all 28 cases, and radiographic control after 6 months showed bone regeneration in all the cases. This technique was effective in isolating the maxillary sinus from the oral cavity, showing results in terms of seal and healing, and bone regeneration., Clinical Significance: Oroantral communications are frequent in dentistry, requiring special expertise and interventions affecting patient morbidity. The use of a heterologous cortical lamina can allow effective closure of the communication, preventing migration of pathological epithelia while increasing the bone ridge., Competing Interests: The authors declared no conflict of interest with respect to the research, authorship, and/or publication of this article. Dr. Lopez and Dr. Passarelli contributed equally to this work. Dr. Garcia-Godoy and Dr. D'Addona contributed equally to this work., (Copyright©American Journal of Dentistry.)

Purpose: This retrospective observational study evaluated the histomorphometric and soft tissue outcome of a new alveolar ridge preservation (ARP) technique, "Lamina Socket Sealing" (LSS) technique, using a porcine barrier., Methods: Patients with maxillary premolars to be extracted and extensive alveolar wall defects were enrolled and treated. Porcine-derived barriers and mesenchymal membrane were used to seal the extraction socket with alveolar particulate graft. An optical scan of the dental arches was performed with an intraoral scanner (Trios 3, 3Shape) at baseline and at a 4-month follow-up. At the time of implant placement, a bone sample was taken at the implant site with a trephine drill (Hager & Meisinger) and subjected to histomorphometric analysis., Results: 36 subjects (21 females and 15 males) were treated. At 4 months, histomorphometric analysis of the bone samples revealed that the percentage of vital bone was 42.87%, 8.75% of residual granules, 30.76% of soft tissue. Linear comparison of the width of the keratinized gingiva showed an increase (mean + SE) of 3.16 ± 0.35 mm. The net volumetric change of soft tissue was (mean + SE) +28.41 ± 19.52 mm³., Clinical Significance: This alveolar ridge preservation technique (Lamina Socket Sealing) using a resorbable heterologous cortical lamina with a flapless approach has proven effective in maintaining adequate soft tissue and grafting of particulate bone and lamina, with a high percentage of viable bone., Competing Interests: The authors declared no conflict of interest for the research, authorship, and/or publication of this article. Dr. Passarelli and Dr. Lopez contributed equally to this work. Dr. Chiapasco and Dr. D'Addona contributed equally to this work, (Copyright©American Journal of Dentistry.)

Purpose: This retrospective observational study aims to evaluate the outcome of a new alveolar ridge preservation (ARP) technique, "Lamina Socket Sealing" (LSS) technique, using a porcine barrier., Methods: 36 subjects with maxillary premolars to be extracted and extensive alveolar wall defects were enrolled and treated. Porcine-derived barriers and mesenchymal membrane were used to seal the extraction socket with alveolar particulate graft. The outcome variables were: radiographical bone changes and clinical outcomes., Results: 36 subjects, 21 females and 15 males were treated. The change in mm (mean + SE) of horizontal ridge width from baseline to 4 months after surgery at the coronal level of the alveolus was +1.25 ± 0.20 mm (P< 0.05), mean level was +0.34 ± 0.1 mm (P< 0.05) and at the apical level was +0.08 ± 0.17 mm (P> 0.05) which was not statistically significant. The buccal and palatal height changes in mm (mean + SE) from baseline to 4 months after surgery were respectively 1.21 ± 0.17 mm for the buccal wall (P< 0.05) and 1.06 ± 0.24 mm for the palatal wall (P< 0.05). The bone volume of all sites allowed for the placement of the planned implants., Clinical Significance: The alveolar ridge preservation technique (Lamina Socket Sealing) using resorbable heterologous cortical lamina with flapless approach allowed not only the preservation of the damaged post-extraction socket, but also minimal ridge augmentation, according to the principles of guided bone regeneration., Competing Interests: The authors declared no conflict of interest with respect to the research, authorship, and/or publication of this article. Dr. Passarelli and Dr. Lopez contributed equally to this study. Dr. Chiapasco and Dr. D'Addona contributed equally to this study., (Copyright©American Journal of Dentistry.)

Purpose: To provide an overview of an innovative surgical approach to guided bone regeneration, the Pack Into Bone (PIB) technique., Methods: Twenty subjects, eight men and 12 women, aged 34 to 68 (mean 51.5) were selected. They were treated with the PiB technique, and upon re-entry surgery, performed 8 months postoperatively, implants were placed, and bone samples were collected by using trephine burs for histological and histomorphometric analysis purposes., Results: Mean ridge width varied between 4.71 (W0) mm and 7.37 mm (W1), measured 8 months postoperatively, with a mean W augmentation of 2.69 mm ± 0.19. Mean height ranged between 8.0 mm (H0) and 11.15 mm (H1), measured 8 months after surgery with a mean augmentation of 3.53 mm ± 0.14 (P< 0.05)., Clinical Significance: Stability and versatility are the pillars of the PIB technique compared to common GBRs. The PIB technique is effective and reduces the difficulty in stabilizing the graft, is more feasible for operators, and decreases morbidity for the subjects., Competing Interests: The authors disclose no conflict of interest concerning the research, authorship, and/or publication of this article. Dr. Lopez and Dr. Passarelli contributed equally to this work. Dr. Garcia-Godoy and Dr. D'Addona contributed equally to this work., (Copyright©American Journal of Dentistry.)

The rising demand for effective bone regeneration has underscored the limitations of traditional methods like autografts and allografts, including donor site morbidity and insufficient biological signaling. This review examines nanoparticles (NPs) in tissue engineering (TE) to address these challenges, evaluating polymers, metals, ceramics, and composites for their potential to enhance osteogenesis and angiogenesis by mimicking the extracellular matrix (ECM) nanostructure. The methods involved synthesizing and characterizing nanoparticle-based scaffoldsand integrating hydroxyapatite (HAp) with polymers to enhance mechanical properties and osteogenic potential. The results showed that these NPs significantly promote cell growth, differentiation, and bone formation, with carbon-based NPs like graphene and carbon nanotubes showing promise. NPs offer versatile, biocompatible, and customizable scaffolds that enhance drug delivery and support bone repair. Despite promising results, challenges with cytotoxicity, biodistribution, and immune responses remain. Addressing these issues through surface modifications and biocompatible molecules can improve the biocompatibility and efficacy of nanomaterials. Future research should focus on long-term in vivo studies to assess the safety and efficacy of NP-based scaffolds and explore synergistic effects with other bioactive molecules or growth factors. This review underscores the transformative potential of NPs in advancing BTE and calls for further research to optimize these technologies for clinical applications.

Effective management of head and neck cancer (HNC) poses a significant challenge in the field of oncology, due to its intricate pathophysiology and limited treatment options. The most common HNC malignancy is head and neck squamous cell carcinoma (HNSCC). HNSCC treatment includes a combination of surgery, radiation, and chemotherapy. While HNSCC is treatable if diagnosed early, this is often not the case and is considered incurable once in its late stages and metastatic disease has developed. Therapies are also limited once resistant disease has occurred. SP-1-39, a novel colchicine-binding site inhibitor (CBSI), has been recently reported for its potential efficacy in a variety of cancer cell lines including breast, melanoma, pancreatic, and prostate. SP-1-39 also shows abilities to overcome paclitaxel resistance in a paclitaxel-resistant prostate cancer xenograft model. To evaluate the potential of SP-1-39 as a new HNSCC treatment option, herein we systematically performed preclinical studies in HNSCC models using SP-1-39 and demonstrated that, in vitro, SP-1-39 inhibits the proliferation of 2 HNSCC cell lines with low nanomolar IC 50 values (1.4 to 2.1 nM), induces HNSCC cell apoptosis in a dose-dependent manner, interferes with migration of HNSCC cells, and leads to HNSCC cell cycle arrest in the G2/M phase. In vivo, SP-1-39 suppresses the primary tumor growth of a Detroit 562 subcutaneous xenograft mouse model in 6- to 8-wk-old, male NSG (NOD.Cg-Prkdc scid Il2rg tm1Wjl /SzJ) mice, with no detectable cytotoxic effects at a low dose of 2.5 mg/kg. This efficacy of SP-1-39 is better when compared with the treatment using a reference chemotherapy drug, paclitaxel at 10 mg/kg. Collectively, these data demonstrate that SP-1-39 is a promising candidate for further development for more efficacious HNSCC treatment., Competing Interests: Declaration of Conflicting InterestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: W.L. and D.D.M. are listed as inventors for compound SP-1-39 described in this study. W.L. and D.D.M. also received sponsored research agreements (SRAs) from Veru, Inc., although the SRAs are not directly related to this study. W.L. is scientific consultant for Veru, Inc. However, Veru, Inc. did not have any influence on this study and only required reviewing this study prior to submission for publication for potential intellectual property purposes.

Purpose: To evaluate the in vitro antibacterial effect of Softsoap and Efferdent used as solutions to disinfect Lucitone 199 poly(methyl methacrylate) (PMMA) resin used for dentures., Methods: S. mutans and plaque bacteria were grown for 24 hours, and suspended to a concentration of 1x10⁶ cells/ml. Bacterial suspensions (0.2 mL) were added to the decontaminated PMMA discs placed in a 48-well culture plate and incubated for 3 days at 37°C. The discs were rinsed to remove the unbound bacterial cells and then incubated for 60 minutes with 5% and 1% dilutions (triplicates) of each of the detergent solutions (0.3 ml). Discs were rinsed and then MTT reagent (0.2 ml) was added and incubated for 2 hours, then overnight with a solubilizing agent. An aliquot from each well (0.1 ml) was transferred to a 96-well flat bottom plate and absorbance was measured to OD @ 595 nm (MTT) of four samples for each data point. Normalized data was compared and statistically analyzed using a three-way ANOVA with Student-Newman-Keuls on Rank data with P< 0.05 for significance. Additionally, data were double-checked with the Holm-Sidak test., Results: There was no statistically significant difference between testing media for C. albicans and mixed plaque (P= 0.078) or testing duration in time at 24 hours and 21 days (P= 0.07). Statistically significant differences were found between all treatment solutions group combinations (P< 0.001) except for 30% Softsoap versus Efferdent (P= 0.056)., Clinical Significance: There was no statistically significant difference between testing media for C. albicans and mixed plaque (P= 0.078) or testing duration at 24 hours and 21 days (P= 0.07). Statistically significant differences were noted between all treatment solutions group combinations (P< 0.001), However, there was no difference between 30% Softsoap and Efferdent (P= 0.056)., Competing Interests: The authors declared no conflict of interest., (Copyright©American Journal of Dentistry.)

Purpose: To investigate the discoloration, line roughness and gloss of conventional and universal shade resin-based composites., Methods: Clearfil AP-X (AP-X) and Estelite Sigma Quick (EQ) samples were prepared. Discoloration, roughness, and gloss were measured on mirror-polished, alkaline-degraded, and repolished surfaces. The superficial layer degraded by alkaline immersion (degraded layer) was ground off from the sample surface. After removing the degraded layer, the surface was polished with aluminum oxide powder (1.0 µm and 0.3 µm), to create a repolished specimen. Scanning electron microscopy observations were made of the specimens., Results: The results were compared with those for Omnichroma (OC) from a previous study. All the materials showed different responses to degradation and repolishing, but repolishing of AP-X, for surface roughness and gloss, was more effective at restoring pre-degradation properties. Repolishing effectively removed discoloration in all materials., Clinical Significance: The materials tested showed different responses to degradation and repolishing, but repolishing of AP-X, for surface roughness and gloss, was more effective at restoring pre-degradation properties. Repolishing effectively removed discoloration in all materials., Competing Interests: The authors declared no conflict of interest. This work was supported by JSPS KAKENHI (Grant-in-Aid for Early-Career Scientists) Grant Number 23K16011., (Copyright©American Journal of Dentistry.)

Purpose: The purpose of this study was to investigate the microleakage of atraumatic glass ionomer restorations with and without silver diammine fluoride (SDF) application. Restorations with SDF are termed silver-modified atraumatic restorations (SMART). Methods: Sixty carious extracted permanent teeth were randomly allocated to two SMART groups and two control groups (n equals 15 per group) for a total of four groups. After selective caries removal, test specimens were treated with 38 percent SDF and polyacrylic acid conditioner was applied and rinsed; teeth were restored with Fuji IX GP® glass ionomer (n equals 15) or with SMART Advantage™ glass ionomer (SAGI; n equals 15). For control groups, specimens were restored with their respective GI material after selective caries removal, both without SDF. Restored teeth were placed in Dulbecco's Phosphate-Buffered Saline solution at 37 degrees Celsius for 24 hours. Teeth were thermocycled between five and 55 degrees Celsius for 1,000 cycles, stained with two percent basic fuchsin, sectioned, and visually inspected for microleakage utilizing stereomicroscopy on a four-point scale. Data were statistically analyzed using Kruskal-Wallis one-way analysis of variance on ranks using Dunn's method (P<0.05). Results: Microleakage between the two SMART restoration groups was insignificant. SAGI alone demonstrated significantly more microleakage than all other groups. There was no statistical significance between the Fuji IX GP® control group and the two SMART restoration groups. Conclusions: This in vitro study indicated that silver diammine fluoride placed before glass ionomer restoration does not increase microleakage. Polyacrylic acid may be used after SDF placement without increasing microleakage.

Purpose: To investigate the effect of painless low-power Er:YAG laser irradiation of conventional and polymer-infiltrated ceramic network (PICN) type CAD-CAM resin-based composites (RBCs) on resin bonding., Methods: An Er:YAG laser system, phosphoric acid etchant, universal adhesive, RBC, and two types of CAD-CAM RBC block were used. Microtensile bond strength, fracture mode, scanning electron microscopy (SEM) observations of bonding interfaces and CAD-CAM surfaces, and surface roughness of ground and pretreated surfaces were investigated. As pretreatment methods, low-power Er:YAG laser irradiation and air-abrasion with alumina particles were used., Results: The effect of low-power Er:YAG laser irradiation of CAD-CAM RBCs on bonding to repair resin varied depending on the type of CAD-CAM RBCs., Clinical Significance: The low-power Er:YAG laser irradiation of the conventional CAD-CAM RBCs was shown to be effective as a surface pretreatment for resin bonding, while the laser irradiation of PICN-type CAD-CAM RBCs was not effective., Competing Interests: The authors declared no conflict of interest. This work was supported by JSPS KAKENHI [Grant-in-Aid for Scientific Research(C)] Grant Number 23K09190., (Copyright©American Journal of Dentistry.)

Objectives: To provide a 3-year follow-up of previously treated patients to assess and compare the periodontal responses and clinical performance of proximal subgingival open sandwich restorations., Materials and Methods: Ninety-five adults participated in the study, with a combined total of 120 compound Class II cavities. These cavities had gingival margins located below the CEJ. Four different restorative materials were used to elevate the dentin/cementum gingival margins of the cavities: resin-modified glass ionomer, glass hybrid, flowable bulk-fill composite, or ion-releasing material, which were then completed with the same overlaying composite. Different periodontal and clinical evaluations, based on the criteria set by the World Dental Federation (FDI) criteria, were performed at different time intervals, including baseline, 6 months, 1, 2, and 3 years., Results: The type of base material did not affect the periodontal evaluations. There were no statistically significant differences between different time intervals or base material groups in any of the evaluated FDI parameters. However, the ion-releasing material scored significantly worse in the radiographic evaluation than any of the other groups., Conclusions: All tested materials are suitable for proximal subgingival open sandwich restorations, as long as the restoration/tooth margin is at least 2-mm away from the bone crest., Clinical Significance: Clinicians can confidently choose any of the tested materials for proximal subgingival open sandwich restorations, as they have shown good outcomes from both periodontal and clinical perspectives., (© 2023 Wiley Periodicals LLC.)

This study aimed to evaluate the periodontal responses of subgingival proximal margins elevated using different restorative materials. A total of 120 proximal cavities with dentin/cementum gingival margins were elevated using one of four materials (resin-modified glass ionomer, glass hybrid, flowable bulk-fill resin composite, or bioactive ionic resin) and completed with the same overlaying resin composite. At 2 weeks (baseline), 6 months, 1 year, and 2 years postrestoration, periodontal parameters and the radiographic distance between the restoration margin and bone crest were evaluated. Appropriate statistical analyses were performed. The values of all periodontal parameters increased with time, although only the increases in Plaque Index and probing depth within each material group were statistically significant. There were no statistically significant differences in any of the periodontal parameters between the different materials within the same evaluation period, nor between different time points or material groups in the radiographic distances. Both glass ionomer-based and resin-based materials were periodontally safe as subgingival open sandwich restorations.

Purpose: To evaluate the influence of group and individual education on shade matching quality using a visual color competency test to match shade tab pairs from two Vita classical A1-D4 shade guides., Methods: 60 dental students, 21-25 years old (39 females, 21 males) participated in the study. All participants passed a color deficiency test before the experiment. The examination was voluntary and approved by the corresponding Ethics Committee. Students were randomly divided into three groups (n=20): one control group, NE (no education) and two experimental groups - GE (group education) and IE (individual education). The study was performed in three phases. In the "before" (B - Phase 1) and "after" (A - Phase 3) phase, all groups had to match 16 pairs of tabs from two Vita classical A1-D4 shade guides, with the shade designations hidden by custom letter markings. All tabs were mixed on a gray surface illuminated by color-correcting light. In Phase 2 (between B and A), GE had only group education, while IE received additional individual education and training. The control group did not participate in Phase 2. Means and standard deviations were calculated, and differences were compared using the one-way ANOVA, ANCOVA test, and Student t-test for dependent samples (α= 0.05)., Results: The NE group matched 10.3 (3.2) and 10.4 (2.9) tab pairs in the before and after phases, respectively. Corresponding results for GE were 11.1 (2.2) and 14.4 (1.9) and 9.5 (3.6) and 15.0 (1.5) for IE, respectively. In Phase 1 (B), no statistically significant difference was recorded among the groups (P= 0.260). The experimental groups achieved a statistically significant improvement compared with the control group in Phase 3 (A) (P< 0.001). Both experimental groups achieved statistically significant improvement within the group after education, GE (P< 0.001) and IE (P< 0.001). Within the limitations of this study, it was concluded that both experimental groups had statistically significant progress in shade matching. The group that received individual education (IE) made statistically significant progress compared with the group that received group education (GE). No statistically significant difference was found in the results of the control group between Phase 1 and Phase 3 of the study., Clinical Significance: Improving the shade matching ability facilitates the work of dentists and dental technicians and enhances the esthetics of dental restorations., Competing Interests: The authors declared no conflict of interest. Dr. Paravina is a consultant for VITA Zahnfabrik., (Copyright©American Journal of Dentistry.)

Purpose: To evaluate the effectiveness of whitening toothpaste in restoring tooth color after coffee staining and its potential impact on enamel surfaces compared with regular toothpaste., Methods: Bovine tooth enamel specimens were prepared and stained with coffee solutions before undergoing brushing simulation with different toothpaste slurries (whitening, regular, reference). For precise evaluation, spectrophotometric measurements were taken at intervals to assess color changes using the CIELAB (Commission Internationale de l'Éclairage Lab*) color space. Additionally, profilometric measurements were taken to determine the impact of toothpaste type on the roughness and abraded depth of the enamel surface. To understand the effects of toothpaste and brushing on color change, surface roughness, and abraded depth, while also considering correlations between these factors, the findings were analyzed using mixed-effects models., Results: The whitening toothpaste group demonstrated the highest recovery rate (71%) after 10,000 brushstrokes, followed by the regular toothpaste group (48%) and the reference slurry group (43%). The mixed-effects model analysis revealed that the reference group had a smaller change in lightness (ΔL) than those in the regular toothpaste group. The whitening toothpaste group showed a greater change in lightness on average than those in the regular toothpaste group, with an increase in lightness as the number of brushstrokes increased. According to the roughness and abraded depth data, the whitening toothpaste group was least affected by brushing, while the reference and regular toothpaste groups showed higher levels of roughness and abraded depth at all intervals., Clinical Significance: Gaining a thorough understanding of the effectiveness of whitening toothpaste and its impact on the enamel surface plays a crucial role in refining toothpaste formulations and advancing tooth whitening techniques in dental care., Competing Interests: The authors declare no conflicts of interest related to this research. Ms. Kim and Dr. Yoo contributed equally to this work. This research was supported by Korea Medical Device Development Fund grant funded by the Korea government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, the Ministry of Food and Drug Safety) (Project Number: 1711134912, RS-2020-KD000002), and partly supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2021R1l1A2048516)., (Copyright©American Journal of Dentistry.)

Purpose: To evaluate flow profile and non-Newtonian behavior of 10 different silicone lining materials., Methods: Ten commercially available silicone lining materials were selected for evaluation. The flow profile and non-Newtonian behavior of each material was measured using a shark fin testing method. Fin height and resultant base thickness were measured with a digital caliper and compared with one-way ANOVA and Student-Newman-Keuls post hoc test and fin base by Kruskal-Wallis one-way ANOVA on ranks with Dunn post hoc test with significance at P< 0.05 for both., Results: Shark fin heights ranged from 9.62 ± 0.86 mm [Reline II (Soft)] to 25.54 ± 0.43 mm [Sofreliner (Medium)]. Shark fin bases ranged from 2.57 ± 0.51 mm [Sofreliner (Medium)] to 10.31 ± 0.57 mm [Reline II (Soft)]. Statistically significant differences were found between certain samples' shark fin heights as well as resultant bases (P< 0.05) indicating different rheological properties., Clinical Significance: Silicone liner materials differ significantly with respect to flow profile and non-Newtonian behavior. While a high flow profile (low viscosity) of an elastomeric impression material improves accuracy, it may be a detriment to a denture lining material that must achieve a critical minimum thickness to provide resilience. Likewise, a low flow profile (high viscosity) material may also pose a disadvantage, requiring excessive compression and possible tissue distortion to achieve the same critical thickness. The results of this study should be considered when selecting the appropriate material for clinical application. Additional studies are indicated to further quantify rheological properties as well as correlate them to physical properties after the complete cure of the material., Competing Interests: The authors declared no conflict of interest., (Copyright©American Journal of Dentistry.)

Objectives: This study aimed to investigate the elemental analysis and microhardness of a bioactive material (Activa) and marginal tooth structure after storage in different media., Materials and Methods: Fifteen teeth received cervical restorations with occlusal enamel and gingival dentin margins using the tested material bonded with a universal adhesive, 5 of them on the 4 axial surfaces and the other 10 on only the 2 proximal surfaces. The first 5 teeth were sectioned into 4 restorations each, then stored in 4 different media; deionized water, Dulbecco's phosphate buffered saline (DPBS), Tris buffer, and saliva. The storage period for deionized water was 24 hours while it was 3 months for the other media. Each part was analyzed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis for different substrates/distances and the wt% of calcium, phosphorus, silica, and fluoride were calculated. The other 10 teeth were sectioned across the restoration, stored in either Tris buffer or saliva for 24 hours or 3 months, and were evaluated for microhardness of different substrates/areas. Data were analyzed using analysis of variance and Tukey's post hoc test., Results: Enamel and dentin interfaces in the DPBS group exhibited a significant increase in calcium and phosphorus wt%. Both silica and fluoride significantly increased in tooth structure up to a distance of 75 μm in the 3-month-media groups than the immediate group. Storage media did not affect the microhardness values., Conclusions: SEM-EDS analysis suggests an ion movement between Activa and tooth structure through a universal adhesive while stored in DPBS., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2024. The Korean Academy of Conservative Dentistry.)

Purpose: To evaluate the amount of dentin loss following immersion in or toothbrushing with whitening toothpaste (WT) containing hydrogen peroxide (HP) and citric acid (CA). Additionally, the amount of dentin loss after brushing with a WT alone or in combination with a conventional toothpaste was assessed, and the effects of HP and CA solutions on the dentin surface were investigated., Methods: Bovine dentin specimens (n= 350) were randomly assigned to seven solutions of various compositions as toothpaste: The specimens assigned to each solution were then further divided into five treatment groups (n=10 each) : Group A = 1-hour immersion in each solution (ES); Group B = 10,000 brushing in ES; Group C = 1-hour immersion in ES + 10,000 brushing in ES; Group D = 1-hour immersion in ES + 10,000 brushing in reference slurry (RS); Group E = 10,000 brushing in ES + 10,000 brushing in RS. The amount and pattern of dentin loss were determined, and the surfaces were observed using noncontact profilometry., Results: The WT (pH 5.0) caused lower dentin loss than RS after a single brushing cycle; however, the extent of dentin loss after 1 hour of immersion in the WT was significantly greater than that in the RS. Among the specimens treated with WT, a significant difference in dentin loss was observed between Group C and Groups D and E (P< 0.05) but not between Groups D and E. The surfaces exposed to CAS1, CAPB, and WT exhibited U-shaped patterns of dentin loss after brushing or immersion, whereas a wedge-shaped pattern was observed in those that underwent brushing with the RS., Clinical Significance: The effects (dentin abrasion) of a whitening toothpaste containing hydrogen peroxide and citric acid when used in combination with a conventional toothpaste were similar to those seen with the continuous use of a conventional toothpaste alone., Competing Interests: The authors declared no conflict of interest. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2021R1l1A204851611)., (Copyright©American Journal of Dentistry.)

Purpose: To compare the microhardness values and bottom/top hardness ratios of different composites after being cured in 2 or 4 mm increments., Methods: Two bulk fill composites, methacrylate-based and ormocer-based, and one conventional composite were tested. 36 cylindrical discs were prepared (n=12/composite, with six for 2 mm, and six for 4 mm thickness) by pressing each composite into a mold between two glass slides covered by Mylar strips. The top and bottom surfaces of each sample were evaluated using a Buehler hardness tester for Knoop microhardness, with a 50 g static load applied for 10 seconds at three different locations of the central part of each sample. The bottom/top hardness ratio was calculated for each sample. The Knoop microhardness data and bottom/top ratio percentages were analyzed using two-way repeated measures ANOVA and Holm-Sidak post hoc test, with significance at P< 0.05., Results: The tested methacrylate-based bulk fill had the highest overall microhardness among the three tested composites. All three composite types showed a significant difference in microhardness between the top and bottom of the 4 mm discs. The bottom/top ratio percentages differed significantly for both tested bulk fill composites across different thicknesses. Both tested bulk fill materials had a bottom/top ratio of ≥ 80% at the deepest level of a 4 mm increment., Clinical Significance: The type of material significantly affected both the bottom and top microhardness values under the experimental conditions used. While both tested bulk fill composites showed a decline in microhardness at the bottom of the 4 mm depth, they had clinically acceptable microhardness ratios at greater depths., Competing Interests: The authors declared no conflict of interest. Supported by the University of Tennessee Health Science Center College of Dentistry Alumni Endowment Fund and the Tennessee Dental Association Foundation., (Copyright©American Journal of Dentistry.)

Aerosols produced by dental handpieces represent a permanent risk of disease transmission in the dental environment. The current study evaluated the effects of natural ventilation (open windows) on Streptococcus mutans airborne contamination by dental handpieces in simulated clinical conditions. A dental phantom was placed on a dental chair at a standard university dental clinic operatory. An S. mutans suspension was infused into the phantom's mouth while an operator performed standardized dental procedures using low (contra-angle) and high speed (turbine) dental handpieces or an ultrasonic scaler, with windows open or closed. Selective medium Petri dishes were placed in 18 sites of the operatory environment to evaluate contamination topographically. Sites were clustered as: wall, floor, ceiling, dental chair, and cabinet. Contamination was expressed as log 10 CFU/cm 2 . A linear mixed model analysis was used, nesting the sites within each ventilation and handpiece combination. Open windows significantly reduced contamination. The high-speed handpiece provided the highest contamination, followed by the ultrasonic scaler and the low-speed handpiece. Contamination values were much smaller at the ceiling, and much larger at the chair. Opening windows produced more homogeneous contamination of the operatory compared to closed windows. Natural ventilation during dental procedures decreases contamination and affects its topographical distribution., (© 2023 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

Background: To determine the safety of Botox and its potential effect on alleviating radiation therapy (RT)-induced sialadenitis in head and neck cancer patients., Methods: Twenty patients with stage III/IV head and neck cancer were randomized to receive Botox or saline injections into both submandibular glands (SMG). There were three visits: one before RT (V1); 1 week after RT (V2); and 6 weeks after RT (V3), each of which included saliva collection, a 24-h dietary recall, and a quality-of-life survey., Results: No adverse events were observed. While the control group was much older, the Botox group more commonly underwent induction chemotherapy compared with controls. From V1 to V2, salivary flow decreased in both groups, but only in the control group from V1 to V3. CXCL-1 (GRO), a neutrophil chemoattractant, was lower in the Botox group compared with the control group at V3., Conclusion: Botox can be safely administered to the salivary glands prior to external beam radiation without observed complications or side-effects. After an initial reduction in salivary flow following RT, the Botox group showed lack of further flow reduction compared with controls. The inflammatory marker CXCL 1, which was reduced in the in Botox group at V3, may be a candidate for further studies of radiation-induced sialadenitis., (© 2023 Wiley Periodicals LLC.)

Purpose: To evaluate and compare the effects of different scaling and polishing techniques on the surface roughness of four different restorative materials., Methods: 72 specimens were prepared, molded to a size of 8.0 by 2.0 mm, and cured according to the manufacturers' instructions. The specimens were stored at 37°C for 24 hours and then thermocycled for 5,000 cycles (from 55°C to 5°C) to simulate 6 months of clinical use. Surface roughness (Ra/average and Rz/max-overall heights) was calculated using a stylus profilometer by subtracting the simulated treatments of hand scaling, ultrasonic scaling, and air polishing from the baseline measurements. The difference in Ra and Rz data were compared independently for each measurement using a two-way ANOVA on Ranks and the Holm-Sidak test, with α< 0.05 used to determine significance., Results: Irrespective of the scaling or polishing technique employed, flowable bulk fill demonstrated the lowest Ra and Rz values. Hand scaling exhibited the highest roughness and variability among the other techniques, regardless of the materials tested (P< 0.001). Air polishing with glycine resulted in the lowest roughness values across all tested materials, with the exception of the tested bioactive restorative material group., Clinical Significance: Regarding surface roughness, air polishing with glycine may be an effective and safe intervention for periodontal maintenance of subgingival restorations compared to the other tested scaling methods., Competing Interests: The authors declared no conflict of interest. Supported by the University of Tennessee Health Science Center College of Dentistry Alumni Endowment Fund and the Tennessee Dental Association Foundation., (Copyright©American Journal of Dentistry.)

Purpose: To evaluate the potential secondary caries reduction of bulk-fill resin composite restorations treated with different fluoride (F)-based agents prior to restoration placement., Methods: 25 upper extracted molars received Class V cavities on both buccal and lingual surfaces with an enamel margin and root surface margin. The teeth were randomly assigned into five groups with five teeth per group (n=10). The treatment groups were: control group, with no treatment; the other groups received treatment using different F-based agents prior to bonding. All teeth were restored using a selective etch bonding technique and bulk fill resin composite. All teeth received 10,000 thermal cycles followed by immersion in demineralizing solution to produce artificial caries-like lesions. Polarized light microscope evaluation was performed on longitudinal sections (30 enamel lesions and 30 root surface lesions per group). Lesion depth and wall lesions for both enamel and root surface adjacent to the restorations were evaluated., Results: Both lesion depths and frequency of wall lesions in the enamel and root surfaces in all treatment groups were significantly reduced compared with the control group. Among the different F-based agents, no significant difference was seen on the enamel or root surface lesion depth, showing a similar presence of enamel and root cavosurface wall lesions., Clinical Significance: F-based agent treatment of adjacent enamel and root surfaces prior to placement of restorative materials provided resistance to the development of secondary caries during an in vitro caries model., Competing Interests: The authors declared no conflict of interest., (Copyright©American Journal of Dentistry.)

Purpose: To evaluate the effects of toothpaste tablets on the gloss and surface roughness of resin-based composite materials and determine the relationship between gloss and roughness., Methods: Rectangular jigs were designed and printed. Wells (2 mm deep x 7 mm diameter) were filled with Filtek Supreme Ultra A2B, light-cured and polished. A small-area glossmeter was used for gloss (GU) measurements and a profilometer for roughness measurements (Ra) at baseline and after challenge with each toothpaste. An automated tooth-brushing machine was set at 120 strokes/minute for a total of 10,000 strokes to evaluate four test groups with 16 specimens in each group. NC: Brushing with distilled water; TABS: Colgate Anywhere Travel Tooth Tabs; CP: Colgate Cavity Protection Toothpaste and AW: Colgate Whitening Advanced Toothpaste. Kruskal-Wallis test was used to test the difference in gloss and surface roughness among the groups and Pearson correlation was used to compare the relationship between gloss and roughness., Results: There was no statistically significant difference in gloss and roughness among the four groups at baseline. At post-brushing, there was a statistically significant difference among the groups (P< 0.001) with increased roughness and decreased gloss for CP and AW when compared to TABS. There was a statistically significant correlation between post-brushing roughness and post-brushing gloss (P< 0.001, rho: -0.815). Thus, the higher the surface roughness the lower the gloss., Clinical Significance: Toothpaste tablets retain better gloss and roughness of resin-based composite materials when compared to conventional toothpastes., Competing Interests: The authors declared no conflict of interest. The study was supported by the Loma Linda University School of Dentistry Student Research Program Fund., (Copyright©American Journal of Dentistry.)

This in-silico investigation evaluated the mechanical impact of Morse tape implant-abutment interface and retention system (with and without screw) and restorative materials (composite block and monolithic zirconia) by means of a three-dimensional finite element analysis (3D-FEA). Four 3D models were designed for the lower first molar. A dental implant (4.5 × 10 mm B&B Dental Implant Company) was digitized (micro CT) and exported to computer-aided design (CAD) software. Non-uniform rational B-spline surfaces were reconstructed, generating a 3D volumetric model. Four different models were generated with the same Morse-type connection, but with a different locking system (with and without active screw) and a different crown material made of composite block and zirconia. The D2 bone type, which contains cortical and trabecular tissues, was designed using data from the database. The implants were juxtaposed inside the model after Boolean subtraction. Implant placement depth was simulated for the implant model precisely at crestal bone level. Each acquired model was then imported into the finite element analysis (FEA) software as STEP files. The Von Mises equivalent strains were calculated for the peri-implant bone and the Von Mises stress for the prosthetic structures. The highest strain values in bone tissue occurred in the peri-implant bone interface and were comparable in the four implant models (8.2918e-004-8.6622e-004 mm/mm). The stress peak in the zirconia crown (64.4 MPa) was higher than in the composite crown (52.2 MPa) regardless of the presence of the prosthetic screw. The abutment showed the lowest stress peaks (99.71-92.28 MPa) when the screw was present (126.63-114.25 MPa). Based on this linear analysis, it is suggested that the absence of prosthetic screw increases the stress inside the abutment and implant, without effect on the crown and around the bone tissue. Stiffer crowns concentrate more stress on its structure, reducing the amount of stress on the abutment., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Epifania et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Purpose: To compare the amount of abrasion of four whitening toothpastes, two conventional toothpastes, and seven experimental toothpastes with varying concentrations of hydrogen peroxide., Methods: Bovine dentin specimens were treated with the four whitening toothpastes (containing three different concentrations of hydrogen peroxide: 0.75%, 1.50%, and 2.80%), two conventional toothpastes without hydrogen peroxide, seven experimental toothpastes (concentrations of hydrogen peroxide: 0.75%, 1.50%, 3.0%, 4.50%, 6.0%, 7.50%, and 9.0%), and distilled water. After 10,000 strokes of toothbrushing, the amount of abrasion on the dentin surface was measured with a contactless 3D surface profiler (n= 8). The pH of all solutions, the weight percentages of the particles, and the component of particles in the toothpaste were analyzed. The correlations between the dentin abrasion, pH, and weight percentages of the particles in the toothpastes were investigated., Results: The amount of abrasion of the two conventional toothpastes were 1.1-3.6 times higher than those of the four whitening toothpastes. Likewise, the pH of the conventional toothpaste was higher than those of the other whitening toothpastes. No significant differences were found among the four whitening toothpastes. The four whitening toothpastes consisted of a relatively lower weight percentage of particles compared to the two conventional toothpastes. A strong positive correlation was observed between the dentin abrasion and the weight percentages of the particles (r= 0.913; P< 0.05). Furthermore, no significant differences in the amount of abrasion were observed between the specimens treated with seven experimental toothpastes and those treated with distilled water., Clinical Significance: The whitening toothpastes containing less than 9% hydrogen peroxide did not seem to harm the dentin surface significantly. These findings can serve as a reference for consumers, patients, and dental professionals., Competing Interests: The authors declared that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1I1A2048516)., (Copyright©American Journal of Dentistry.)

This study compared the periodontopathic bacterial adhesion to four restorative materials used for deep margin elevation at 2, 24, and 48-h after incubation. Discs were produced from four restorative materials: resin modified glass ionomer, glass hybrid, flowable bulk fill resin composite, and bioactive ionic resin. Root dentin was used as control. Specimens were coated with saliva and used to culture a biofilm comprised of three strains of periodontopathic bacteria; Porphyromonas gingivalis, Prevotella intermedia, and Aggregatibacter actinomycetemcomitans. Bacterial adherence was assessed by colony count assay, crystal violet staining, and visualized using confocal laser scanning microscopy. Data were analyzed by two-way ANOVA followed by Tukey's post hoc tests. The adhesion values for the control specimens were significantly higher than for other materials, while those for the flowable bulk fill were significantly lower than for any other material within all evaluation assays. The 2-h incubation period showed the lowest adhesion values regardless of the group. The 48-h adhesion values were higher than the 24-h results in all groups except the flowable bulk fill. Microscopic imaging partially supported the findings of the measurements. In terms of periodontopathic bacterial adhesion, the tested flowable bulk fill may be preferable for subgingival use over other tested materials., (© 2022 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

The aim of this study is to compare the marginal seal and tensile bond strength (TBS) of prostheses fixed to enamel-dentin using different adhesive systems. Resin-composite inlays directly fabricated from Class V cavities of extracted human molars/premolars and mini-dumbbell-shaped specimens of bonded enamel-dentin were prepared for microleakage and tensile tests, respectively. Four adhesive systems were used: primerless-wet (1-1 etching for 10-, 30-, or 60-s, and 4-META/MMA-TBB), primer-moist (All-Bond2 + Duolink or Single-Bond2 + RelyX ARC), self-etch (AQ-Bond + Metafil FLO), and dry (Super-Bond C&B) bonding. Dye penetration distance and TBS data were recorded. Failure modes and characteristics of the tooth-resin interface were examined on the fractured specimens. All specimens in 10-, 30-, and 60-s etching primerless-wet, Super-Bond, and AQ-Bond had a microleakage-free tooth-resin interface. Primer-moist groups showed microleakage at the cementum/dentin-resin margin/interface. Significantly higher TBSs (p < 0.05) were recorded in primer-less-wet and Super-Bond groups with the consistent hybridized biopolymer layer after the chemical challenge and mixed failure in tooth structure, luting-resin, and at the PMMA-rod interface. There was no correlation between microleakage and TBS data (p = −0.148). A 1−3 µm hybrid layer created in the 10−60 s primerless-wet technique, producing complete micro-seal and higher tensile strength than enamel and cured 4-META/MMA-TBB, may enhance clinical performances like Super-Bond C&B, the sustainable luting resin.

Purpose: To test the feasibility of nitrogen-doped TiO₂ nanoparticles in the killing of Streptococcus mutans (S. mutans) for short term treatment., Methods: For the study, S. mutans were treated with the combinations of N-TiO₂, visible light, and without/with 0.5% H₂O₂ inclusion. Visible light was irradiated for 3 minutes one time., Results: Methylene blue solution was degraded (bleached) 5-30% by one of N-TiO₂ (or TiO₂) + visible laser (405 or 660 nm) +0.5% H₂O₂ conditions owing to almost linearly producing free radicals through photocatalysis. Antibacterial outcomes treated with N-TiO₂ were slightly better than those by TiO₂ regardless of test condition. Also, killing of S. mutans treated with 405 nm laser was slightly better than those by 660 nm laser., Clinical Significance: S. mutans can be eliminated using N-TiO₂ with clinically acceptable light (wavelength, intensity) and low concentration H₂O₂ condition under short term treatment., Competing Interests: The authors declared no conflict of interest. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MIST) (2019R1F1A1051140)., (Copyright©American Journal of Dentistry.)

Purpose: To test the efficacy of nitrogen doped-TiO₂ (N-TiO₂) nanoparticles (NPs) on teeth whitening under visible light irradiation., Methods: N-TiOV₂ NPs were prepared by the sol-gel method, using TiN as a precursor. Their light absorbance and crystal structures were characterized. Photocatalytic reactions were tested using methylene blue (MB) and extracted teeth. For the extracted teeth, carbomer gel, without or with 3% H₂O₂, and light irradiated, with subsequent evaluation of the color differences., Results: Unlike ordinary TiO₂, N-TiO₂ showed high absorbance after 400 nm. N-TiO₂ prepared with TiN as a precursor showed rutile phase over the TiN structure. For MB solution, N-TiO₂ with 3% H₂O₂ showed the maximum decrease in absorbance after laser irradiation. Observing the effect on teeth, N-TiO₂+3% H₂O₂+405 nm laser treatment achieved approximately 25% higher whitening than that by 15% H₂O₂ during the same treatment time. Higher H₂O₂ concentrations may offer faster results., Clinical Significance: N-TiO₂ nanoparticles (without or with 3% H₂O₂) show better whitening of teeth as compared to 15% H₂O₂, if used with a visible laser for 5 hours. The potential on N-TiO₂ nanoparticles to be used as a tooth whitener needs to be further explored to reduce its application time., Competing Interests: The authors declared no conflict of interest. This study was supported by Dental Research Institute (PNUDH DRI-2022-03), Pusan National University Dental Hospital, Yangsan, S. Korea., (Copyright©American Journal of Dentistry.)

The purpose of this study was to compare the envelope flap and triangular flap for impacted lower third molar (M3) extraction and their effects on the periodontal health of adjacent second molars (M2). A population of 60 patients undergoing M3 extraction with the envelope flap (Group A) or triangular flap (Group B) was analyzed, comparing probing pocket depth (PPD), clinical attachment level (CAL), and gingival recession (REC) recorded at six sites (disto-lingual, mid-lingual, mesio-lingual, disto-vestibular, mid-vestibular, and mesio-vestibular) before (T 0 ) and 6 months after extraction (T 1 ). There was a statistically significant mean difference in PPD and CAL at two sites, disto-vestibular (dv) and disto-lingual (dl), between values recorded before and 6 months after surgery for either Group A or Group B. Furthermore, for the same periodontal records, at 6 months after surgery, a statistically significant difference was recorded between younger and older patients, implying that the healing process was more beneficial for younger patients. No significant differences were found between the two groups (A and B) in PPDdl, PPDdv, CALdl, and CALdv, confirming that the mucoperiosteal flap design does not influence the periodontal healing process of second molars.

Purpose: To compare the autofluorescence (AF) spectra of resin products with teeth to determine if this type of non-invasive testing is feasible for differentiating resin products from teeth during resin repair., Methods: For the study, 11 methacrylate-based resin products were chosen. A 405 nm laser was used to induce AF, and a spectrophotometer and a qualitative laser-induced fluorescence (QLF) camera were used to obtain AF spectra and images, respectively., Results: Resin products and teeth showed one or two emission peak(s) at 435-465 nm and 475-480 nm, respectively. Other resin constituents produced weak emission peaks beyond the 435-475 nm range. Resin products with high emission intensities produced bright images. When layered, surface resins (0.2 mm-thick) were different from underlying base resins and teeth., Clinical Significance: During resin repair, a restored resin can be readily removed if AF spectroscopy is used alone or in combination with QLF imaging., Competing Interests: The authors declared no conflicts of interest. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MIST) (2019R1F1A1058667)., (Copyright©American Journal of Dentistry.)

Purpose: To evaluate and compare the effect of pressure during curing on resin composite bond strength to dentin using a self-etch bonding protocol., Methods: 20 human teeth were cut to the mid-coronal dentin and received a standardized smear layer. The prepared teeth were randomly assigned to the following two groups (n= 10/group): (1) without pressure during curing (control) or (2) with pressure during curing. Teeth in the control group received a 4 mm-thick buildup of a nanohybrid resin composite in two separately cured increments, adapted using a composite placement instrument, and bonded with a universal adhesive, while teeth in the treatment group were restored with the same adhesive and resin composite but a plexiglass pressure cylinder was used to apply pressure while each increment was cured. Each group was further divided into two subgroups, one of which was sectioned and subjected to microtensile bond strength (µTBS) testing after 24 hours (immediate samples; n= 5), while the other was subjected to 10,000 thermal cycles (TC; n= 5) prior to sectioning and µTBS testing. The resulting failure patterns were assessed under a stereomicroscope. In addition, one representative specimen from each subgroup was subjected to qualitative microscopic morphological analysis of the internal restoration/dentin interface. Data were analyzed by two-way ANOVA followed by Tukey' post hoc test and values with P< 0.05 were considered to be statistically significant., Results: After TC, the group cured with pressure exhibited significantly higher µTBS values than did the control (P< 0.05), although TC had a detrimental effect on all µTBS values. Microscopic examination revealed that the control specimens had more voids in the resin composite part, relative to specimens that were under pressure during the curing process., Clinical Significance: Pressure application during curing of resin composite may have a positive effect on bond strength to dentin., Competing Interests: The authors declared no conflict of interest., (Copyright©American Journal of Dentistry.)

Purpose: The purpose of this study was to evaluate the surface roughness of three different brands of prefabricated pediatric zirconia crowns (ZRCs) following simulated toothbrushing with a variety of dentifrices. Methods: Ninety-six total maxillary right central incisor prefabricated pediatric ZRCs (n equals 32 ZRCs/brand) were obtained from the manufacturers: Kinder Krowns ® , NuSmile ® , and Sprig ® . ZRCs were equally assigned to dentifrices (n equals eight/dentifrice) with a variety of Relative Dentin Abrasion (RDA) values: Tom's of Maine Children's; Crest Kid's; Prevident 5000; and Crest ® Pro-Health. ZRCs were brushed 10,000 strokes with a V-8 Toothbrushing Machine using the assigned dentifrices. Pre- and post-intervention data for the surface roughness of ZRCs, represented in Ra (average roughness) and Rz (mean roughness depth), were obtained using a stylus profilometer. Data were analyzed independently using two-way repeated measures analysis of variance with the Holm- Sidak method (α equals 0.05). Results: Baseline versus brushed Ra Kinder Krowns ® with Prevident and Sprig ® with Crest Kid's indicated statistically significant differences. Sprig ® versus NuSmile ® utilizing Crest Kid's were different in change in roughness. Both baseline and brushed NuSmile ® dentifrice options were different versus all Sprig ® and Kinder ® ZRCs. Conclusions: Despite statistical significance, changes in surface roughness were small in scale. Although this study did not address toothbrushing and different dentifrices may affect the mechanical properties, durability, and/or retention properties of ZRCs, the study's results provide confidence to clinicians when using prefabricated pediatric ZRCs as a sustainable treatment option along with other restorative options, such as strip crowns and stainless steel crowns.

Objectives: This study aimed to evaluate the effect of aging on the marginal quality of glass hybrid (GH) material used to elevate dentin gingival margins, and to analyze the consistency of the results obtained by 3 in vitro methods., Materials and Methods: Ten teeth received compound class II cavities with subgingival margins. The dentin gingival margins were elevated with GH, followed by resin composite. The GH/gingival dentin interfaces were examined through digital microscopy, scanning electron microscopy (SEM) using resin replicas, and according to the World Dental Federation (FDI) criteria. After initial evaluations, all teeth were subjected to 10,000 thermal cycles, followed by repeating the same marginal evaluations and energy dispersive spectroscopy (EDS) analysis for the interfacial zone of 2 specimens. Marginal quality was expressed as the percentage of continuous margin at ×200 for microscopic techniques and as the frequency of each score for FDI ranking. Data were analyzed using the paired sample t -test, Wilcoxon signed-rank test, and Pearson and Spearmen correlation coefficients., Results: None of the testing techniques proved the significance of the aging factor. Moderate and strong significant correlations were found between the testing techniques. The EDS results suggested the presence of an ion-exchange layer along the GH/gingival dentin interface of aged specimens., Conclusions: The marginal quality of the GH/dentin gingival interface defied aging by thermocycling. The replica SEM and FDI ranking results had stronger correlations with each other than either showed with the digital microscopy results., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2022. The Korean Academy of Conservative Dentistry.)

Purpose: To test the applicability of autofluorescence (AF) spectrum and image in the detection and identification of oral pathogens., Methods: Oral pathogens (Candida albicans, Porphyromonas gingivalis, Streptococcus mutans) and teeth were used. To induce AF, the 405 nm laser was used as a light source, and AF was obtained and observed using a spectrometer, fluorescence camera, and microscope, respectively., Results: The tested oral pathogens had similar spectral distributions, but their peak intensities and peak ratios were different. Their peak positions and spectral patterns were different from those of the tested sound and carious teeth. These differences were also found from the other referenced oral mucosa. Fluorescence image could localize the existence of oral bacteria. Oral pathogens could be imaged by fluorescence, but identification of each pathogen by image was not probable., Clinical Significance: Oral pathogens can be observed and identified from the lesion if autofluorescence spectrum and fluorescence images are combined., Competing Interests: The authors declared no conflict of interest. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MIST) (2019R1F1A1058667) and (2019R1F1A1051140)., (Copyright©American Journal of Dentistry.)

Purpose: To investigate and compare the effects of the two widely used regenerative endodontics medicaments: Triple antibiotic paste (ciprofloxacine-metronidazole-clindamycin) and calcium hydroxide on the microhardness and degradation of human root dentin., Methods: Following ethical approval and subject consent to use teeth in this research study, 60 singled-rooted permanent human teeth were randomly divided into six groups:(1) Tri-antibiotic paste with distilled water, or with (2) propylene glycol, (3) calcium hydroxide with distilled water, (4) calcium hydroxide propylene glycol, (5) untreated extracted teeth as negative controls, or (6) teeth instrumented and filled with calcium hydroxide or tri-antibiotic paste as positive controls. The microhardness tests were conducted after 1 and 2 months of exposure to the medicaments using a Vickers microhardness tester. Raman spectroscopy and energy dispersive x-ray spectroscopy were used to evaluate the chemistry and structure of the root dentin., Results: There were differences in the dentin microhardness following treatment with the medicaments or controls (P< 0.05). The time of root dentin exposure to the medicaments was similar (P> 0.05). The root dentin microhardness was lower in the teeth treated with the triple antibiotic paste or calcium hydroxide when combined with propylene glycol. The root dentin collagen in these treated teeth were also significantly degraded when viewed with Raman spectroscopy and energy dispersive x-ray spectroscopy, whereas the inorganic phase (dentin) remained unaltered. Samples exposed to the antimicrobial agents with water as a vehicle exhibited stronger microhardness and less degradation., Clinical Significance: These ex vivo results suggest that the triple antibiotic paste and calcium hydroxide should be used with propylene glycol if a fast diffusion is desired or with water to avoid degrading the collagen and weakening the microhardness of the teeth. Clinical trials are needed of new formulations of medicaments with propylene glycol to disinfect teeth for regenerative endodontic procedures, to help strengthen the teeth to prevent the loss of children's permanent immature teeth by fracture following caries or trauma., Competing Interests: The authors declared no conflict of interest., (Copyright©American Journal of Dentistry.)

Paracrine factors secreted in the conditioned media (CMs) of periodontal ligament-derived stem cells (PDLSCs) have been shown to downregulate inflammatory effects of interleukin (IL)-1β on chondrocytes wherein milk fat globule-epidermal growth factor 8 (MFG-E8) is one of the PDLSCs' highly secretory proteins. Therefore, the objective of this study was to investigate the ability of PDLSC CMs and MFG-E8 to reduce the inflammatory effects of impact injury on porcine talar articular cartilage (AC) and IL-1β on chondrocytes, respectively. Stem cells were isolated from human periodontal ligaments. The MFG-E8 content in CM collected at 5% and 20% oxygen was measured by ELISA assay and compared across subcultures and donors. AC samples were divided into three groups: control, impact, and impact+CM. Chondrocytes were isolated from pig knees and were divided into three groups: control, IL-1β, and IL-1β+MFG-E8. Gene expression data were analyzed by reverse transcription-polymerase chain reaction. It was found that impact load and IL-1β treatment upregulated IL-1β, TNF-α, ADAMTS-4, and ADAMTS-5 gene expression in AC and chondrocytes, respectively. PDLSCs-CM prevented the upregulation of all four genes due to impact, whereas MFG-E8 prevented upregulation of IL-1β, ADAMTS-4, and ADAMTS-5 in chondrocytes, but it did not prevent TNF-α upregulation. There were no significant differences in MFG-E8 content in CM among oxygen levels, passage numbers, or donors. The findings suggested that MFG-E8 is an effective anti-inflammatory agent contributing to the chondroprotective effects of PDLSCs-CM on acutely injured AC. Thus, introducing PDLSCs-CM to sites of acute traumatic AC injury could prevent the development of post-traumatic osteoarthritis.

Background: There is still debate about the most appropriate restorative material category to relocate the proximal deep cervical margins, thus, this study aimed to compare the marginal and internal adaptation of four base materials used for deep margin elevation, and to evaluate each base material/overlying composite interface., Material and Methods: Fifty six molars received class II cavities with dentin/cementum gingival margins. They were divided into four groups and their gingival margins were elevated using either; resin modified glass ionomer (RMGI), highly viscous conventional glass ionomer (HV-GIC), flowable bulk fill resin composite (Bulk Flow) and bioactive ionic resin (Activa). The rest of the cavities were completed with the same overlying composite. Half of each group was either; kept in sterile water for 1 week, or subjected to 18 months water storage and 15,000 thermal cycles. Base materials/gingival dentin interfaces were examined under a scanning electron microscope at different magnifications, and percentage of continuous margin (% CM) and maximum gap width (MGW) were analyzed, in addition to base materials/overlying composite interfaces evaluations. % CM values were statistically analyzed using Two-way analysis of variance, Tukey post hoc tests (at p <0.05) and Pearson's correlation while MGW values were analyzed using Kruskal-Wallis, Mann-Whitney U tests and Spearmen correlation., Results: Both Bulk Flow and Activa had better marginal integrity than RMGI and HV-GIC. All base materials were adversely affected by aging. All base materials/overlying composite interfaces were continuous and age defying., Conclusions: In terms of marginal integrity, Bulk Flow and Activa might be preferable for proximal dentin margin elevation under direct restoration compared to the other tested base materials. Key words: Deep proximal margin, interface analysis, marginal quality, open sandwich technique., Competing Interests: Conflicts of interest The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of this paper., (Copyright: © 2022 Medicina Oral S.L.)

Purpose: To evaluate the laboratory long-term effect of various whitening dentifrices on the surface roughness of two brands of resin composite (TPH ST, Filtek Bulk Fill One) using a mechanical toothbrushing simulation., Methods: Thirty-two samples each of Filtek and TPH were fabricated in ring molds 10 x 1 mm. Samples were randomly grouped (n=8; four groups), according to dentifrice used; Crest 3D, Optic White, Hello (charcoal), and Aim as control. Samples were brushed in mixed solutions containing deionized water and dentifrice at 150 gf for 10,000x with rotation to ensure uniform brushing. Surface roughness was measured both before (baseline) and after the mechanical toothbrushing simulation using a stylus profilometer. Data collected was compared independently for each treatment using two-way ANOVA and SNK with α< 0.05 for significance., Results: The data showed that TPH was more susceptible to the abrasive nature of three of the whitening dentifrices tested [Crest 3D, Optic White, and Hello (charcoal) ]. Filtek also exhibited significant susceptibility to the abrasive nature of Hello. Aim showed the least or minimal amount of abrasion., Clinical Significance: TPH ST composite was more susceptible to the abrasive nature of the three whitening dentifrices tested [Crest 3D, Optic White, and Hello (charcoal)]. Filtek also exhibited significant susceptibility to the abrasive nature of Hello. Aside from the data supporting the clinical efficacy of TPH compared to Filtek, clinicians should inform patients of the abrasive capacity of all whitening dentifrices, especially those that are charcoal based., Competing Interests: The authors declared no conflict of interest. Supported in part by the University of Tennessee Health Science Center College of Dentistry Alumni Endowment Fund and the Tennessee Dental Association Foundation., (Copyright©American Journal of Dentistry.)

To examine the effect of mold enclosure and chisel design on macro shear fatigue bond strengths of dental adhesive systems. The fatigue bond strength testing was conducted with two commercially available dental adhesive systems, (1) OptiBond eXTRa and (2) Scotchbond Universal, for bonding a resin composite (Filtek Supreme Ultra) to both enamel and dentin using a mold enclosure and a non-mold enclosure with a knife-edge and two sized notched-edge chisel assemblies for loading. As a loading reference for the fatigue testing, macro shear bond strengths of the adhesive systems to enamel and dentin were conducted using a mold enclosure and a knife-edge chisel assembly. The shear bond strengths with the mold enclosure using knife-edge chisel assembly did not exhibit a significant difference between the adhesive systems for either enamel or dentin. The fatigue bond strengths of bonded specimens demonstrated significant differences when comparing the mold enclosure and non-mold enclosure, but not between knife-edge and notched-edge chisel assemblies. The fatigue bond strengths of dental adhesive systems demonstrated significantly higher values when using mold-enclosed bonded specimens than a non-mold enclosure, regardless of type of chisel assembly., (© 2022 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

The present investigation evaluated the effect of the combination of different dental filling materials in Class I cavities under occlusal loading using three-dimensional finite elements analysis (FEA). Six computer-generated and restored models of a lower molar were created in the CAD software and compared according to the biomechanical response during chewing load condition. Two adhesively bonded bulk restorative materials [bulk-fill resin composite (BF) or Alkasite (Alk)] were evaluated with or without the presence of a base material below (flowable resin composite or glass ionomer cement). A food bolus was placed on the occlusal surface mimicking the compressive occlusal load (600 N) during the static linear analysis. The maximum principal stress (tensile) was calculated as stress criteria in enamel, dentin and restoration. All models showed high stresses along the enamel/restoration margin with a similar stress trend for models restored with the same upper-layer material. Stress values up to 12.04 MPa (Alk) or up to 11.12 MPa (BF) were recorded at the enamel margins. The use of flexible polymeric or ionic base material in combination with bulk-fill resin composite or Alk did not reduce the stress magnitude in dentine and enamel. Class I cavities adhesively restored with bulk-fill resin composite showed lighter stress concentration as well as Alk. Therefore, adhesively bonded Alk restoration showed a promising mechanical behavior when used with different base materials or as a bulk restoration for posterior Class I cavity.

Purpose: To quantify the biological contamination of a dental operatory environment using a biological tracer., Methods: A Streptococcus mutans suspension was infused into the mouth of a phantom, and an operator performed standardized dental procedures using an air turbine, a contra-angle handpiece, or an ultrasonic scaler either with windows open or closed. The presence of the tracer was measured by placing Petri dishes with a selective medium at 18 sites on the dental unit and 38 sites in the surrounding operatory environment., Results: The contamination was drastically reduced when windows were opened, no matter which handpiece was used. Air turbine spread significantly higher contamination compared to contra-angle and scaler. All tested instruments spread the tracer over the entire dental unit and the surrounding environment, including the walls and ceiling; however, higher contamination levels were detected on the dental unit compared to the operatory surfaces. Opening windows during dental operative procedures greatly reduced contamination levels for all handpieces and can be recommended for reducing airborne contamination levels., Clinical Significance: The significant levels of airborne contamination produced when operating dental handpieces can be significantly reduced by natural ventilation, i.e., simply opening the windows., Competing Interests: The authors declared no conflict of interest., (Copyright©American Journal of Dentistry.)

Purpose: To analyze the biological effects of four base materials used for elevation of proximal subgingival margins on gingival epithelial cells., Methods: Twenty-eight specimens for each of the four base materials (total 112 specimens) were used: resin-modified glass ionomer (RMGI), glass hybrid (HV-GIC), flowable bulk fill resin composite (Bulk Flow) and bioactive ionic resin (Activa). Proximal enamel and root dentin were used as controls. Gingival epithelial cell viability was calculated after direct incubation on all four types of material for either 24 h or 72 h using both the methyl tetrazolium and trypan blue dye exclusion assays. Data were analyzed statistically using one-way analysis of variance, Tukey post hoc test and independent sample t-test (P < 0.05)., Results: Cell viability values in both assays showed significant differences among the study groups. Bulk Flow showed the highest values, followed in order by Activa and the control groups. Both HV-GIC and RMGI had the lowest values. Cell viability in all of the study groups was higher after incubation for 72 h than after 24 h., Conclusion: In terms of biocompatibility with epithelial tissues, bulk fill resin composite appears to be most suitable, followed by bioactive composite, for subgingival placement than glass ionomer-based materials, especially that containing 2-hydroxy-ethyl methacrylate.

To compare full and partial coverage crowns made with different CAD/CAM leucite reinforced ceramic blocks on fracture resistance and fractographic analysis. Full coverage and partial coverage crowns with finish line at 2 mm and 4 mm above the gingiva for molars made with IPS Empress CAD and Rosetta BM. After fatigue process, the fracture test and fractographic analysis were conducted. Although the fracture resistance of IPS Empress crowns did not show any statistical differences regardless of the design, both the partial coverage crowns fabricated using Rosetta BM showed significantly higher load at break and peak load than the full coverage crown. The crowns made with IPS Empress showed significantly higher fracture resistance than that made with Rosetta BM, regardless of the restorative design. The fracture resistance and fractographic analysis of CAD/CAM leucite reinforced full and partial coverage crowns were influenced by the restorative design of and material type.

Purpose: To determine the efficacy of an oral spray and oral rinses to inhibit oral cariogenic dual species biofilm formation on hydroxyapatite (HA) discs., Methods: The Streptococcus mutans (NCTC 10449, ATCC), Lactobacilli casei (NCIB 8820, ATCC) dual species biofilm formation and inhibition on HA disc was tested using five antimicrobial products, i.e., oral spray (Oral Shield), Mouthrinse (Listerine Ultra Clean, Listerine Cool Mint, Crest Pro-Health, ACT Restoring). An untreated group served as control. The established biofilm on the surface of each disc was treated or untreated with oral spray and mouthrinse for 2 minutes after 24 or 48 hours. The dual species biofilm formation and inhibition on HA discs was determined using the spread plate method and colonies were counted and expressed as colony forming units (CFU/mL). Further, the HA disc was subjected to confocal laser scanning microscope (CLSM) examination to determine the viability of cells using live-dead staining and a scanning electron microscope (SEM) to examine the effect on bacteria biofilm and morphology. The cytotoxic effect of test spray and mouthrinse was tested on OKF6/TERT-2 cells using the MTT method., Results: At each time point, 24- or 48-hours, S. mutans and L. casei mixed biofilm on HA discs had a significantly (P> 0.001) fewer number of bacteria in the treated groups than the untreated one. The oral spray and mouthrinses had a detrimental effect on bacteria biofilm, morphology and cell wall, whereas no significant changes were observed in the untreated group. Cytotoxic assay revealed that the oral spray was safe for human oral keratinocyte cells., Clinical Significance: The tested oral spray could offer potential to inhibit the cariogenic bacteria and protect the tooth enamel from cariogenic bacterial biofilm., Competing Interests: Dr. Azees, Dr. Wang, Dr. Chen and Dr. Yeh have no conflict of interest. Dr. Garcia-Godoy was involved in developing the formulation for the Oral Shield spray., (Copyright©American Journal of Dentistry.)